{"id":221,"date":"2021-01-12T23:23:59","date_gmt":"2021-01-12T15:23:59","guid":{"rendered":"https:\/\/blog.indeex.club\/?p=221"},"modified":"2021-10-13T09:56:57","modified_gmt":"2021-10-13T01:56:57","slug":"%e6%95%b0%e5%ad%a6%e6%80%9d%e6%83%b3%e7%9a%84%e4%bb%a3%e7%a0%81%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/blog.indeex.club\/index.php\/2021\/01\/12\/%e6%95%b0%e5%ad%a6%e6%80%9d%e6%83%b3%e7%9a%84%e4%bb%a3%e7%a0%81%e5%ae%9e%e7%8e%b0\/","title":{"rendered":"\u6570\u5b66\u601d\u60f3\u7684\u4ee3\u7801\u5b9e\u73b0"},"content":{"rendered":"<hr \/>\n<p>\u6574\u7406\u4e00\u4e0b\uff0c\u4ee5\u4fbf\u4ee5\u540e\u67e5\u9605\u3002<\/p>\n<h1>\u524d\u8a00<\/h1>\n<p>\u6570\u5b66\u7b26\u53f7\u53ef\u4ee5\u8868\u793a\u4e0d\u540c\u7684\u610f\u601d\uff0c\u8fd9\u53d6\u51b3\u4e8e\u4f5c\u8005\uff0c\u4e0a\u4e0b\u6587\u548c\u6240\u5b66\u4e60\u7684\u9886\u57df\uff08\u7ebf\u6027\u4ee3\u6570\uff0c\u96c6\u5408\u7406\u8bba\uff0c\u7b49\u7b49\uff09\u3002<\/p>\n<p>\u7b80\u5355\u8d77\u89c1\uff0c\u8fd9\u91cc\u8bb8\u591a\u7684\u4ee3\u7801\u793a\u4f8b\u90fd\u64cd\u4f5c\u6d6e\u70b9\u6570\u503c\u3002<\/p>\n<h1>\u76ee\u5f55<\/h1>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u53d8\u91cf\u540d\u7ea6\u5b9a\">\u53d8\u91cf\u540d\u7ea6\u5b9a<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u7b49\u53f7\">\u7b49\u53f7 <code>=<\/code> <code>\u2248<\/code> <code>\u2260<\/code> <code>:=<\/code><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5e73\u65b9\u6839\u4e0e\u590d\u6570\">\u5e73\u65b9\u6839\u4e0e\u590d\u6570 <code>\u221a<\/code> <em><code>i<\/code><\/em><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u70b9--\u53c9\">\u70b9 &amp; \u53c9 <code>\u00b7<\/code> <code>\u00d7<\/code> <code>\u2218<\/code><\/a>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u6807\u91cf\u4e58\u6cd5\">\u6807\u91cf\u4e58\u6cd5<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5411\u91cf\u4e58\u6cd5\">\u5411\u91cf\u4e58\u6cd5<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u70b9\u4e58\">\u70b9\u4e58<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u53c9\u4e58\">\u53c9\u4e58<\/a><\/li>\n<\/ul>\n<\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u897f\u683c\u739bsigma\">\u897f\u683c\u739b <code>\u03a3<\/code><\/a> &#8211; <em>\u6c42\u548c<\/em><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5927\u5199-pi\">\u5927\u5199 Pi <code>\u03a0<\/code><\/a> &#8211; <em>\u5e8f\u5217\u7684\u79ef<\/em><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u7ba1\u9053pipes\">\u7ba1\u9053 <code>||<\/code><\/a>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u7edd\u5bf9\u503c\">\u7edd\u5bf9\u503c<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u6b27\u51e0\u91cc\u5f97\u6a21\">\u6b27\u51e0\u91cc\u5f97\u6a21<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u884c\u5217\u5f0f\">\u884c\u5217\u5f0f<\/a><\/li>\n<\/ul>\n<\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5e3d\u5b50\">\u5e3d\u5b50 <strong><code>\u00e2<\/code><\/strong><\/a> &#8211; <em>\u5355\u4f4d\u5411\u91cf<\/em><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5c5e\u4e8e\">&#8220;\u5c5e\u4e8e&#8221; <code>\u2208<\/code> <code>\u2209<\/code><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5e38\u89c1\u6570\u5b57\u96c6\">\u5e38\u89c1\u6570\u5b57\u96c6 <code>\u211d<\/code> <code>\u2124<\/code> <code>\u211a<\/code> <code>\u2115<\/code><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u51fd\u6570\">\u51fd\u6570 <code>\u0192<\/code><\/a>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5206\u6bb5\u51fd\u6570\">\u5206\u6bb5\u51fd\u6570<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u901a\u7528\u51fd\u6570\">\u901a\u7528\u51fd\u6570<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u51fd\u6570\u7b26\u53f7\">\u51fd\u6570\u7b26\u53f7 <code>\u21a6<\/code> <code>\u2192<\/code><\/a><\/li>\n<\/ul>\n<\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u6487\u53f7prime\">\u6487\u53f7 <code>\u2032<\/code><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5411\u4e0b\u53d6\u6574\u548c\u5411\u4e0a\u53d6\u6574floor--ceiling\">\u5411\u4e0b\u53d6\u6574\u548c\u5411\u4e0a\u53d6\u6574\uff08floor &amp; ceiling\uff09 <code>\u230a<\/code> <code>\u2309<\/code><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u7bad\u5934\">\u7bad\u5934<\/a>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u5b9e\u8d28\u8574\u542bmaterial-implication\">\u5b9e\u8d28\u8574\u542b\uff08material implication\uff09 <code>\u21d2<\/code> <code>\u2192<\/code><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u7b49\u5f0fequality\">\u7b49\u5f0f <code>&lt;<\/code> <code>\u2265<\/code> <code>\u226b<\/code><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u4e0econjunction--\u6216disjunction\">\u4e0e &amp; \u6216 <code>\u2227<\/code> <code>\u2228<\/code><\/a><\/li>\n<\/ul>\n<\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u903b\u8f91\u975elogical-negation\">\u903b\u8f91\u975e <code>\u00ac<\/code> <code>~<\/code> <code>!<\/code><\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u533a\u95f4intervals\">\u533a\u95f4\uff08intervals\uff09<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"#\u66f4\u591a\">\u66f4\u591a&#8230;<\/a><\/li>\n<\/ul>\n<h2>\u53d8\u91cf\u540d\u7ea6\u5b9a<\/h2>\n<p>\u6709\u5f88\u591a\u547d\u540d\u7ea6\u5b9a\u53d6\u51b3\u4e8e\u4e0a\u4e0b\u6587\u548c\u6240\u5b66\u9886\u57df\uff0c\u4ed6\u4eec\u5e76\u4e0d\u592a\u4e00\u81f4\u3002\u7136\u800c\u5728\u4e00\u4e9b\u6587\u732e\u4e2d\u4f60\u4f1a\u53d1\u73b0\u53d8\u91cf\u540d\u9075\u5faa\u4e00\u4e9b\u6a21\u5f0f\uff0c\u4f8b\u5982\uff1a<\/p>\n<ul>\n<li><em>s<\/em> &#8211; \u659c\u4f53\u5c0f\u5199\u5b57\u6bcd\u7528\u505a\u6807\u91cf \uff08\u4f8b\u5982\u4e00\u4e2a\u6570\u5b57\uff09<\/li>\n<li><strong>x<\/strong> &#8211; \u7c97\u4f53\u5c0f\u5199\u5b57\u6bcd\u7528\u505a\u5411\u91cf \uff08\u4f8b\u5982\u4e00\u4e2a2D\u70b9\uff09<\/li>\n<li><strong>A<\/strong> &#8211; \u7c97\u4f53\u5927\u5199\u5b57\u6bcd\u7528\u505a\u77e9\u9635 \uff08\u4f8b\u5982\u4e00\u4e2a3D\u53d8\u6362\uff09<\/li>\n<li><em>\u03b8<\/em> &#8211; \u659c\u4f53\u5c0f\u5199\u5e0c\u814a\u5b57\u6bcd\u7528\u505a\u5e38\u91cf\u548c\u7279\u6b8a\u53d8\u91cf \uff08\u4f8b\u5982 <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Spherical_coordinate_system\">\u6b27\u62c9\u89d2 <em>\u03b8<\/em>, <em>theta<\/em><\/a>)<\/li>\n<\/ul>\n<p>\u672c\u6587\u4e5f\u57fa\u4e8e\u8fd9\u4e2a\u683c\u5f0f\u3002<\/p>\n<h2>\u7b49\u53f7<\/h2>\n<p>\u6709\u5f88\u591a\u7b26\u53f7\u5f88\u50cf\u7b49\u53f7 <code>=<\/code> \u3002\u8fd9\u91cc\u6709\u4e9b\u5e38\u89c1\u7684\u4f8b\u5b50\uff1a<\/p>\n<ul>\n<li><code>=<\/code> \u8868\u793a\u76f8\u7b49 \uff08\u503c\u76f8\u540c\uff09<\/li>\n<li><code>\u2260<\/code> \u8868\u793a\u4e0d\u76f8\u7b49 \uff08\u503c\u4e0d\u540c\uff09<\/li>\n<li><code>\u2248<\/code> \u8868\u793a\u7ea6\u7b49\u4e8e \uff08<code>\u03c0 \u2248 3.14159<\/code>\uff09<\/li>\n<li><code>:=<\/code> \u8868\u793a\u5b9a\u4e49 \uff08A \u88ab\u5b9a\u4e49\u4e3a B\uff09<\/li>\n<\/ul>\n<p>\u5728 JavaScript \u4e2d:<\/p>\n<pre><code class=\"language-js line-numbers\">\/\/ \u76f8\u7b49\n2 === 3\n\n\/\/ \u4e0d\u76f8\u7b49\n2 !== 3\n\n\/\/ \u7ea6\u7b49\u4e8e\nalmostEqual(Math.PI, 3.14159, 1e-5)\n\nfunction almostEqual(a, b, epsilon) {\n  return Math.abs(a - b) &lt;= epsilon\n}\n<\/code><\/pre>\n<p>\u4f60\u4e5f\u8bb8\u770b\u8fc7 <code>:=<\/code>\uff0c <code>=:<\/code> \u548c <code>=<\/code> \u7b26\u53f7\u7528\u6765\u8868\u793a <em>\u5b9a\u4e49<\/em>\u3002<sup>[1]<\/sup><\/p>\n<p>\u4f8b\u5982\uff0c\u4e0b\u8fb9\u5b9a\u4e49 <em>x<\/em> \u4e3a 2<em>kj<\/em> \u7684\u522b\u540d\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?x%20%3A%3D%202kj\" alt=\"equals1\" \/><\/p>\n<p><!-- x := 2kj --><\/p>\n<p>\u5728 JavaScript \u4e2d\uff0c\u6211\u4eec\u7528 <code>var<\/code> \u6765 <em>\u5b9a\u4e49<\/em> \u53d8\u91cf\u548c\u63d0\u4f9b\u522b\u540d\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var x = 2 * k * j\n<\/code><\/pre>\n<p>\u7136\u800c\uff0c\u8fd9\u91cc\u7684x\u503c\u662f\u53ef\u53d8\u7684\uff0c\u4ec5\u662f\u5f53\u65f6\u7684\u4e00\u4e2a\u5feb\u7167\u3002\u5728\u67d0\u4e9b\u6709\u9884\u5904\u7406\u5668\u8bed\u8a00\u4e2d\u7684 <code>#define<\/code> \u8bed\u53e5\u624d\u6bd4\u8f83\u63a5\u8fd1\u4e8e\u6570\u5b66\u4e2d\u7684 <em>\u5b9a\u4e49<\/em>\u3002<\/p>\n<p>\u5728JavaScript (ES6) \u4e2d\uff0c\u66f4\u7cbe\u786e\u7684 <em>\u5b9a\u4e49<\/em> \uff0c\u5e94\u8be5\u6709\u70b9\u7c7b\u4f3c\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">const f = (k, j) =&gt; 2 * k * j\n<\/code><\/pre>\n<p>\u4e0e\u6b64\u4e0d\u540c\u7684\u662f\uff0c\u4e0b\u8fb9\u8fd9\u53e5\u8868\u793a\u7684\u662f\u76f8\u7b49\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?x%20%3D%202kj\" alt=\"equals2\" \/><\/p>\n<p><!-- x = 2kj --><\/p>\n<p>\u4e0a\u8fb9\u7684\u7b49\u5f0f\u4e5f\u53ef\u4ee5\u89e3\u91ca\u4e3a\u4e00\u4e2a <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Web\/API\/console\/assert\">\u65ad\u8a00<\/a>:<\/p>\n<pre><code class=\"language-js line-numbers\">console.assert(x === (2 * k * j))\n<\/code><\/pre>\n<h2>\u5e73\u65b9\u6839\u4e0e\u590d\u6570<\/h2>\n<p>\u4e00\u4e2a\u5e73\u65b9\u6839\u8fd0\u7b97\u662f\u8fd9\u79cd\u5f62\u5f0f:<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cleft%28%5Csqrt%7Bx%7D%5Cright%29%5E2%20%3D%20x\" alt=\"squareroot\" \/><\/p>\n<p><!-- \\left(\\sqrt{x}\\right)^2 = x --><\/p>\n<p>\u5728\u7f16\u7a0b\u8bed\u8a00\u4e2d\u6211\u4eec\u4f7f\u7528 <code>sqrt<\/code> \u51fd\u6570\uff0c \u50cf\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var x = 9;\nconsole.log(Math.sqrt(x));\n\/\/=&gt; 3\n<\/code><\/pre>\n<p>\u590d\u6570\u662f <img src=\"http:\/\/latex.codecogs.com\/svg.latex?a&space;&plus;&space;ib\" alt=\"complex\" \/> \u5f62\u5f0f\u7684\u8868\u8fbe\u5f0f\uff0c \u5176\u4e2d <img src=\"http:\/\/latex.codecogs.com\/svg.latex?a\" alt=\"a\" \/> \u662f\u5b9e\u6570\u90e8\u5206\uff0c <img src=\"http:\/\/latex.codecogs.com\/svg.latex?b\" alt=\"b\" \/> \u662f\u865a\u6570\u90e8\u5206\u3002 \u865a\u6570 <img src=\"http:\/\/latex.codecogs.com\/svg.latex?i\" alt=\"i\" \/> \u7684\u5b9a\u4e49\u4e3a\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?i%3D%5Csqrt%7B-1%7D\" alt=\"imaginary\" \/>.<br \/>\n<!-- i=\\sqrt{-1} --><\/p>\n<p>JavaScript\u6ca1\u6709\u5185\u7f6e\u590d\u6570\u7684\u529f\u80fd\uff0c\u4f46\u6709\u4e00\u4e9b\u5e93\u652f\u6301\u590d\u6570\u7b97\u6cd5\u3002\u4f8b\u5982\uff0c <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/mathjs\">mathjs<\/a>:<\/p>\n<pre><code class=\"language-js line-numbers\">var math = require('mathjs')\n\nvar a = math.complex(3, -1)\n\/\/=&gt; { re: 3, im: -1 }\n\nvar b = math.sqrt(-1)\n\/\/=&gt; { re: 0, im: -1 }\n\nconsole.log(math.multiply(a, b).toString())\n\/\/=&gt; '1 + 3i'\n<\/code><\/pre>\n<p>\u8fd9\u4e2a\u5e93\u8fd8\u652f\u6301\u5b57\u7b26\u4e32\u8868\u8fbe\u5f0f\u6c42\u503c\uff0c \u6240\u4ee5\u4e0a\u8fb9\u7684\u53ef\u4ee5\u5199\u4e3a\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">console.log(math.eval('(3 - i) * i').toString())\n\/\/=&gt; '1 + 3i'\n<\/code><\/pre>\n<p>\u5176\u4ed6\u5b9e\u73b0\uff1a<\/p>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/immutable-complex\">immutable-complex<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/complex-js\">complex-js<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"http:\/\/www.numericjs.com\/\">Numeric-js<\/a><\/li>\n<\/ul>\n<h2>\u70b9 &amp; \u53c9<\/h2>\n<p>\u70b9 <code>\u00b7<\/code> \u548c\u53c9 <code>\u00d7<\/code> \u7b26\u53f7\u6839\u636e\u4e0a\u4e0b\u6587\u7684\u4e0d\u540c\u6709\u4e0d\u540c\u7684\u7528\u6cd5\u3002<\/p>\n<p>\u4ed6\u4eec\u53ef\u80fd\u770b\u4e0a\u53bb\u5f88\u660e\u663e\uff0c\u4f46\u5728\u8fdb\u5165\u4e0b\u4e00\u90e8\u5206\u4e4b\u524d\uff0c\u7406\u89e3\u4ed6\u4eec\u4e4b\u95f4\u5fae\u5999\u7684\u4e0d\u540c\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002<\/p>\n<h4>\u6807\u91cf\u4e58\u6cd5<\/h4>\n<p>\u4e24\u4e2a\u7b26\u53f7\u90fd\u53ef\u4ee5\u8868\u793a\u7b80\u5355\u7684\u6807\u91cf\u4e4b\u95f4\u7684\u4e58\u6cd5\u3002\u4e0b\u8fb9\u7684\u5199\u6cd5\u610f\u601d\u76f8\u540c\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?5%20%5Ccdot%204%20%3D%205%20%5Ctimes%204\" alt=\"dotcross1\" \/><\/p>\n<p><!-- 5 \\cdot 4 = 5 \\times 4 --><\/p>\n<p>\u5728\u7f16\u7a0b\u8bed\u8a00\u4e2d\uff0c\u6211\u4eec\u503e\u5411\u7528\u661f\u53f7\u8868\u793a\u76f8\u4e58\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var result = 5 * 4\n<\/code><\/pre>\n<p>\u901a\u5e38\uff0c\u4f7f\u7528\u4e58\u6cd5\u7b26\u53f7\u53ea\u662f\u4e3a\u4e86\u907f\u514d\u610f\u4e49\u6a21\u7cca\uff08\u4f8b\u5982\u4e24\u4e2a\u6570\u5b57\u4e4b\u95f4\u7684\uff09\u3002\u8fd9\u91cc\uff0c\u6211\u4eec\u53ef\u4ee5\u5b8c\u5168\u7701\u7565\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?3kj\" alt=\"dotcross2\" \/><\/p>\n<p><!-- 3kj --><\/p>\n<p>\u5982\u679c\u8fd9\u4e9b\u53d8\u91cf\u8868\u793a\u7684\u662f\u6807\u91cf\uff0c\u5219\u4ee3\u7801\u5e94\u8be5\u8fd9\u6837\u5199:<\/p>\n<pre><code class=\"language-js line-numbers\">var result = 3 * k * j\n<\/code><\/pre>\n<h4>\u5411\u91cf\u4e58\u6cd5<\/h4>\n<p>\u8868\u793a\u5411\u91cf\u548c\u6807\u91cf\u4e4b\u95f4\u76f8\u4e58\uff0c\u6216\u4e24\u5411\u91cf\u7684\u9010\u5143\u7d20\u76f8\u4e58\uff08element-wise multiplication\uff09\uff0c\u6211\u4eec\u4e0d\u7528\u70b9 <code>\u00b7<\/code> \u6216\u53c9 <code>\u00d7<\/code> \u7b26\u53f7\u3002 \u8fd9\u4e9b\u7b26\u53f7\u5728\u7ebf\u6027\u4ee3\u6570\u4e2d\u6709\u4e0d\u540c\u7684\u610f\u601d\uff0c\u540e\u8fb9\u8ba8\u8bba\u3002<\/p>\n<p>\u8ba9\u6211\u4eec\u7528\u4e4b\u524d\u7684\u4f8b\u5b50\uff0c\u4f46\u7528\u5728\u5411\u91cf\u4e0a\u3002\u5bf9\u4e8e\u5411\u91cf\u7684\u9010\u5143\u7d20\u76f8\u4e58\uff08element-wise vector multiplication\uff09\u6765\u8bf4\uff0c\u4f60\u53ef\u80fd\u4f1a\u770b\u5230\u7528\u4e00\u4e2a\u7a7a\u5fc3\u70b9\u6765\u8868\u793a <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Hadamard_product_%28matrices%29\">Hadamard product<\/a>\u3002<sup>[2]<\/sup><\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?3%5Cmathbf%7Bk%7D%5Ccirc%5Cmathbf%7Bj%7D\" alt=\"dotcross3\" \/><\/p>\n<p><!-- 3\\mathbf{k}\\circ\\mathbf{j} --><\/p>\n<p>\u67d0\u4e9b\u65f6\u5019\uff0c\u4f5c\u8005\u53ef\u80fd\u4f1a\u663e\u5f0f\u5b9a\u4e49\u4e00\u4e2a\u4e0d\u540c\u7684\u7b26\u53f7\uff0c\u4f8b\u5982\u5706\u4e2d\u70b9 <code>\u2299<\/code> \u6216\u5b9e\u5fc3\u5708 <code>\u25cf<\/code> \u3002<sup>[3]<\/sup><\/p>\n<p>\u8fd9\u662f\u5bf9\u5e94\u7684\u4ee3\u7801\uff0c\u4f7f\u7528\u6570\u7ec4 <code>[x, y]<\/code> \u6765\u8868\u793a2D\u5411\u91cf\u3002<\/p>\n<pre><code class=\"language-js line-numbers\">var s = 3\nvar k = [ 1, 2 ]\nvar j = [ 2, 3 ]\n\nvar tmp = multiply(k, j)\nvar result = multiplyScalar(tmp, s)\n\/\/=&gt; [ 6, 18 ]\n<\/code><\/pre>\n<p><code>multiply<\/code> \u548c <code>multiplyScalar<\/code> \u51fd\u6570\u5e94\u8be5\u8fd9\u6837:<\/p>\n<pre><code class=\"language-js line-numbers\">function multiply(a, b) {\n  return [ a[0] * b[0], a[1] * b[1] ]\n}\n\nfunction multiplyScalar(a, scalar) {\n  return [ a[0] * scalar, a[1] * scalar ]\n}\n<\/code><\/pre>\n<p>\u540c\u6837\u7684\uff0c\u77e9\u9635\u76f8\u4e58\u4e5f\u4e0d\u7528 <code>\u00b7<\/code> \u6216 <code>\u00d7<\/code> \u7b26\u53f7\u3002 \u77e9\u9635\u4e58\u6cd5\u4f1a\u5728\u540e\u8fb9\u7ae0\u8282\u63d0\u5230.<\/p>\n<h4>\u70b9\u4e58<\/h4>\n<p>\u70b9\u7b26\u53f7 <code>\u00b7<\/code> \u53ef\u7528\u6765\u8868\u793a\u4e24\u5411\u91cf\u4e4b\u95f4\u7684 <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Dot_product\"><em>\u70b9\u4e58<\/em><\/a> \u3002 \u7531\u4e8e\u5176\u503c\u662f\u4e00\u4e2a\u6807\u91cf\uff0c\u901a\u5e38\u88ab\u53eb\u505a <em>\u6807\u91cf\u79ef\uff08scalar product\uff09<\/em> \u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cmathbf%7Bk%7D%5Ccdot%20%5Cmathbf%7Bj%7D\" alt=\"dotcross4\" \/><\/p>\n<p><!-- \\mathbf{k}\\cdot \\mathbf{j} --><\/p>\n<p>\u8fd9\u5728\u7ebf\u6027\u4ee3\u6570\u548c3D\u5411\u91cf\u4e2d\u662f\u975e\u5e38\u5e38\u89c1\u7684\uff0c\u4ee3\u7801\u7c7b\u4f3c\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var k = [ 0, 1, 0 ]\nvar j = [ 1, 0, 0 ]\n\nvar d = dot(k, j)\n\/\/=&gt; 0\n<\/code><\/pre>\n<p>\u7ed3\u679c\u4e3a <code>0<\/code> \u544a\u8bc9\u6211\u4eec\u4e24\u5411\u91cf\u4e92\u76f8\u5782\u76f4. \u8fd9\u662f3\u5143\u7d20\u5411\u91cf\u7684 <code>\u70b9\u4e58<\/code> \u51fd\u6570:<\/p>\n<pre><code class=\"language-js line-numbers\">function dot(a, b) {\n  return a[0] * b[0] + a[1] * b[1] + a[2] * b[2]\n}\n<\/code><\/pre>\n<h4>\u53c9\u4e58<\/h4>\n<p>\u53c9\u4e58\u7b26\u53f7 <code>\u00d7<\/code> \u53ef\u4ee5\u7528\u6765\u8868\u793a\u4e24\u5411\u91cf\u7684 <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Cross_product\"><em>\u53c9\u4e58<\/em><\/a>\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cmathbf%7Bk%7D%5Ctimes%20%5Cmathbf%7Bj%7D\" alt=\"dotcross5\" \/><\/p>\n<p><!-- \\mathbf{k}\\times \\mathbf{j} --><\/p>\n<p>\u5728\u4ee3\u7801\u4e2d\uff0c\u5e94\u8be5\u662f\u8fd9\u6837:<\/p>\n<pre><code class=\"language-js line-numbers\">var k = [ 0, 1, 0 ]\nvar j = [ 1, 0, 0 ]\n\nvar result = cross(k, j)\n\/\/=&gt; [ 0, 0, -1 ]\n<\/code><\/pre>\n<p>\u8fd9\u91cc\u5f97\u5230\u7ed3\u679c\u4e3a <code>[ 0, 0, -1 ]<\/code>\uff0c\u8fd9\u4e2a\u5411\u91cf\u540c\u65f6\u5782\u76f4\u4e8e <strong>k<\/strong> \u548c <strong>j<\/strong> \u3002<\/p>\n<p>\u6211\u4eec\u7684\u53c9\u4e58 <code>cross<\/code> \u51fd\u6570\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function cross(a, b) {\n  var ax = a[0], ay = a[1], az = a[2],\n    bx = b[0], by = b[1], bz = b[2]\n\n  var rx = ay * bz - az * by\n  var ry = az * bx - ax * bz\n  var rz = ax * by - ay * bx\n  return [ rx, ry, rz ]\n}\n<\/code><\/pre>\n<p>\u5411\u91cf\u4e58\u6cd5\uff0c\u53c9\u4e58\uff0c\u70b9\u4e58\u7684\u5176\u4ed6\u5b9e\u73b0\uff1a<\/p>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-vec3\">gl-vec3<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-vec2\">gl-vec2<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/hughsk\/vectors\">vectors<\/a> &#8211; \u5305\u542b n\u7ef4\u5b9e\u73b0<\/li>\n<\/ul>\n<h2>\u897f\u683c\u739b\uff08sigma\uff09<\/h2>\n<p>\u5927\u5199\u5e0c\u814a\u5b57\u6bcd <code>\u03a3<\/code> (Sigma) \u7528\u6765\u8868\u793a <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Summation\">\u603b\u548c Summation<\/a>\u3002 \u6362\u53e5\u8bdd\u8bf4\u5c31\u662f\u5bf9\u4e00\u4e9b\u6570\u5b57\u6c42\u548c\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Csum_%7Bi%3D1%7D%5E%7B100%7Di\" alt=\"sigma\" \/><\/p>\n<p><!-- \\sum_{i=1}^{100}i --><\/p>\n<p>\u8fd9\u91cc, <code>i=1<\/code> \u662f\u8bf4\u4ece <code>1<\/code> \u897f\u683c\u739b\u4e0a\u8fb9\u7684\u6570\u5b57<code>100<\/code>\u4e3a\u6b62\u3002\u8fd9\u4e9b\u5206\u522b\u4e3a\u4e0a\u4e0b\u8fb9\u754c\u3002 &#8220;E&#8221; \u53f3\u8fb9\u7684 <em>i<\/em> \u544a\u8bc9\u6211\u4eec\u6c42\u548c\u7684\u662f\u4ec0\u4e48\u3002\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var sum = 0\nfor (var i = 1; i &lt;= 100; i++) {\n  sum += i\n}\n<\/code><\/pre>\n<p><code>sum<\/code> \u7684\u7ed3\u679c\u4e3a <code>5050<\/code> \u3002<\/p>\n<p><strong>\u63d0\u793a\uff1a<\/strong> \u5bf9\u4e8e\u6574\u6570\uff0c\u8fd9\u4e2a\u7279\u6b8a\u5f62\u5f0f\u53ef\u4ee5\u4f18\u5316\u4e3a\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var n = 100 \/\/ \u4e0a\u8fb9\u754c\nvar sum = (n * (n + 1)) \/ 2\n<\/code><\/pre>\n<p>\u8fd9\u91cc\u6709\u53e6\u4e00\u4e2a\u4f8b\u5b50\uff0c\u8fd9\u91cc\u7684 <em>i<\/em> \uff0c\u6216 \u201c\u60f3\u8981\u6c42\u548c\u7684\u4e1c\u897f\u201d \u662f\u4e0d\u540c\u7684\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Csum_%7Bi%3D1%7D%5E%7B100%7D%282i&plus;1%29\" alt=\"sum2\" \/><\/p>\n<p><!-- \\sum_{i=1}^{100}(2i+1) --><\/p>\n<p>\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var sum = 0\nfor (var i = 1; i &lt;= 100; i++) {\n  sum += (2 * i + 1)\n}\n<\/code><\/pre>\n<p><code>sum<\/code> \u7684\u7ed3\u679c\u4e3a <code>10200<\/code> \u3002<\/p>\n<p>\u8fd9\u4e2a\u7b26\u53f7\u53ef\u88ab\u5d4c\u5957\uff0c\u975e\u5e38\u50cf\u5d4c\u5957\u4e00\u4e2a <code>for<\/code> \u5faa\u73af\u3002 \u4f60\u5e94\u8be5\u5148\u6c42\u548c\u6700\u53f3\u8fb9\u7684\u897f\u683c\u739b\uff0c \u9664\u975e\u4f5c\u8005\u52a0\u5165\u62ec\u53f7\u6539\u53d8\u4e86\u987a\u5e8f\u3002\u7136\u800c\u4e0b\u8fb9\u7684\u4f8b\u5b50\uff0c\u7531\u4e8e\u6211\u4eec\u5904\u7406\u6709\u9650\u7684\u548c\uff0c\u987a\u5e8f\u5c31\u4e0d\u91cd\u8981\u4e86\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Csum_%7Bi%3D1%7D%5E%7B2%7D%5Csum_%7Bj%3D4%7D%5E%7B6%7D%283ij%29\" alt=\"sigma3\" \/><\/p>\n<p><!-- \\sum_{i=1}^{2}\\sum_{j=4}^{6}(3ij) --><\/p>\n<p>\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var sum = 0\nfor (var i = 1; i &lt;= 2; i++) {\n  for (var j = 4; j &lt;= 6; j++) {\n    sum += (3 * i * j)\n  }\n}\n<\/code><\/pre>\n<p>\u8fd9\u91cc\uff0c<code>sum<\/code> \u503c\u4e3a <code>135<\/code>\u3002<\/p>\n<h2>\u5927\u5199 Pi<\/h2>\n<p>\u5927\u5199 Pi \u6216 \u201c\u5927Pi\u201d \u4e0e <a class=\"wp-editor-md-post-content-link\" href=\"#\u897f\u683c\u739bsigma\">\u897f\u683c\u739b<\/a> \u975e\u5e38\u63a5\u8fd1\uff0c \u4e0d\u540c\u7684\u662f\u6211\u4eec\u7528\u4e58\u6cd5\u53d6\u5f97\u4e00\u7cfb\u5217\u6570\u5b57\u7684\u4e58\u79ef\u3002<\/p>\n<p>\u770b\u4e0b\u8fb9\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cprod_%7Bi%3D1%7D%5E%7B6%7Di\" alt=\"capitalPi\" \/><\/p>\n<p><!-- \\prod_{i=1}^{6}i --><\/p>\n<p>\u4ee3\u7801\u5e94\u8be5\u7c7b\u4f3c\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var value = 1\nfor (var i = 1; i &lt;= 6; i++) {\n  value *= i\n}\n<\/code><\/pre>\n<p><code>value<\/code> \u7ed3\u679c\u5e94\u5f97\u5230 <code>720<\/code>\u3002<\/p>\n<h2>\u7ba1\u9053\uff08pipes\uff09<\/h2>\n<p>\u7ba1\u9053\u7b26\u53f7\uff0c\u5c31\u662f <em>\u7ad6\u7ebf\uff08bars\uff09<\/em>\uff0c\u6839\u636e\u4e0a\u4e0b\u6587\u4e0d\u540c\uff0c\u53ef\u4ee5\u8868\u793a\u4e0d\u540c\u610f\u601d\u3002\u4e0b\u8fb9\u7684\u662f3\u79cd\u5e38\u89c1\u7528\u9014 <a class=\"wp-editor-md-post-content-link\" href=\"#\u7edd\u5bf9\u503c\">\u7edd\u5bf9\u503c<\/a>, <a class=\"wp-editor-md-post-content-link\" href=\"#\u6b27\u51e0\u91cc\u5f97\u6a21\">\u6b27\u51e0\u91cc\u5f97\u6a21<\/a>, \u548c <a class=\"wp-editor-md-post-content-link\" href=\"#\u884c\u5217\u5f0f\">\u884c\u5217\u5f0f<\/a>\u3002<\/p>\n<p>\u8fd93\u79cd\u7279\u6027\u90fd\u662f\u63cf\u8ff0\u5bf9\u8c61\u7684 <em>\u957f\u5ea6\uff08length\uff09<\/em> \u3002<\/p>\n<h4>\u7edd\u5bf9\u503c<\/h4>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cleft%20%7C%20x%20%5Cright%20%7C\" alt=\"pipes1\" \/><\/p>\n<p><!-- \\left | x \\right | --><\/p>\n<p>\u5bf9\u4e8e\u6570\u5b57 <em>x<\/em>, <code>|x|<\/code> \u8868\u793a <em>x<\/em> \u7684\u7edd\u5bf9\u503c\u3002\u4ee3\u7801\u4e3a\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var x = -5\nvar result = Math.abs(x)\n\/\/ =&gt; 5\n<\/code><\/pre>\n<h4>\u6b27\u51e0\u91cc\u5f97\u6a21\uff08Euclidean norm\uff09<\/h4>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cleft%20%5C%7C%20%5Cmathbf%7Bv%7D%20%5Cright%20%5C%7C\" alt=\"pipes4\" \/><\/p>\n<p><!-- \\left \\| \\mathbf{v} \\right \\| --><\/p>\n<p>\u5bf9\u4e8e\u5411\u91cf <strong>v<\/strong>\uff0c <code>\u2016v\u2016<\/code> \u662f <strong>v<\/strong> \u7684<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Norm_%28mathematics%29#Euclidean_norm\">\u6b27\u51e0\u91cc\u5f97\u6a21\uff08Euclidean norm\uff09<\/a> \u3002\u4e5f\u53eb\u505a\u5411\u91cf\u7684 &#8220;\u91cf\u7ea7\uff08magnitude\uff09&#8221; \u6216 &#8220;\u957f\u5ea6\uff08length\uff09&#8221; \u3002<\/p>\n<p>\u901a\u5e38\u7528\u53cc\u7ad6\u7ebf\u8868\u793a\u6765\u907f\u514d\u4e0e<em>\u7edd\u5bf9\u503c<\/em> \u7b26\u53f7\u6df7\u6dc6\uff0c\u4f46\u6709\u4e9b\u65f6\u5019\u4e5f\u4f1a\u770b\u89c1\u5355\u7ad6\u7ebf\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cleft%20%7C%20%5Cmathbf%7Bv%7D%20%5Cright%20%7C\" alt=\"pipes2\" \/><\/p>\n<p><!-- \\left | \\mathbf{v} \\right | --><\/p>\n<p>\u8fd9\u91cc\u7684\u4f8b\u5b50\u7528\u6570\u7ec4 <code>[x, y, z]<\/code> \u6765\u8868\u793a\u4e00\u4e2a3D\u5411\u91cf\u3002<\/p>\n<pre><code class=\"language-js line-numbers\">var v = [ 0, 4, -3 ]\nlength(v)\n\/\/=&gt; 5\n<\/code><\/pre>\n<p><code>length<\/code> \u51fd\u6570\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function length (vec) {\n  var x = vec[0]\n  var y = vec[1]\n  var z = vec[2]\n  return Math.sqrt(x * x + y * y + z * z)\n}\n<\/code><\/pre>\n<p>\u5176\u4ed6\u5b9e\u73b0\uff1a<\/p>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/mattdesl\/magnitude\/blob\/864ff5a7eb763d34bf154ac5f5332d7601192b70\/index.js\">magnitude<\/a> &#8211; n-dimensional<\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-vec2\/blob\/21f460a371540258521fd2f720d80f14e87bd400\/length.js\">gl-vec2\/length<\/a> &#8211; 2D vector<\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-vec3\/blob\/507480fa57ba7c5fb70679cf531175a52c48cf53\/length.js\">gl-vec3\/length<\/a> &#8211; 3D vector<\/li>\n<\/ul>\n<h4>\u884c\u5217\u5f0f<\/h4>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cleft%20%7C%5Cmathbf%7BA%7D%20%5Cright%20%7C\" alt=\"pipes3\" \/><\/p>\n<p><!-- \\left |\\mathbf{A}  \\right | --><\/p>\n<p>\u5bf9\u4e8e\u4e00\u4e2a\u77e9\u9635 <strong>A<\/strong>\uff0c <code>|A|<\/code> \u8868\u793a\u77e9\u9635 <strong>A<\/strong> \u7684<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Determinant\">\u884c\u5217\u5f0f\uff08determinant\uff09<\/a>\u3002<\/p>\n<p>\u8fd9\u662f\u4e00\u4e2a\u8ba1\u7b97 2&#215;2 \u77e9\u9635\u884c\u5217\u5f0f\u7684\u4f8b\u5b50\uff0c\u77e9\u9635\u7528\u4e00\u4e2acolumn-major\u683c\u5f0f\u7684\u6241\u5e73\u6570\u6570\u7ec4\u8868\u793a\u3002<\/p>\n<pre><code class=\"language-js line-numbers\">var determinant = require('gl-mat2\/determinant')\n\nvar matrix = [ 1, 0, 0, 1 ]\nvar det = determinant(matrix)\n\/\/=&gt; 1\n<\/code><\/pre>\n<p>\u5b9e\u73b0\uff1a<\/p>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-mat4\/blob\/c2e2de728fe7eba592f74cd02266100cc21ec89a\/determinant.js\">gl-mat4\/determinant<\/a> &#8211; \u4e5f\u53ef\u4ee5\u770b <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-mat3\">gl-mat3<\/a> \u548c <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-mat2\">gl-mat2<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/ndarray-determinant\">ndarray-determinant<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/glsl-determinant\">glsl-determinant<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/robust-determinant\">robust-determinant<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/robust-determinant-2\">robust-determinant-2<\/a> \u548c <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/robust-determinant-3\">robust-determinant-3<\/a>\uff0c\u4e13\u95e8 2&#215;2 \u548c 3&#215;3 \u7684\u77e9\u9635<\/li>\n<\/ul>\n<h2>\u5e3d\u5b50<\/h2>\n<p>\u5728\u51e0\u4f55\u91cc\uff0c\u5b57\u6bcd\u4e0a\u7684 \u201c\u5e3d\u5b50\u201d \u7b26\u53f7\u7528\u6765\u8868\u793a\u4e00\u4e2a<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Unit_vector\">\u5355\u4f4d\u5411\u91cf<\/a>\u3002\u4f8b\u5982\uff0c\u8fd9\u662f\u5411\u91cf <strong>a<\/strong> \u7684\u5355\u4f4d\u5411\u91cf\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Chat%7B%5Cmathbf%7Ba%7D%7D\" alt=\"hat\" \/><\/p>\n<p><!-- \\hat{\\mathbf{a}} --><\/p>\n<p>\u5728\u7b1b\u5361\u5c14\u7a7a\u95f4\u4e2d\uff0c\u5355\u4f4d\u5411\u91cf\u7684\u957f\u5ea6\u4e3a1\u3002\u610f\u601d\u662f\u5411\u91cf\u7684\u6bcf\u4e2a\u90e8\u5206\u90fd\u5728 -1.0 \u5230 1.0 \u4e4b\u95f4\u3002\u8fd9\u91cc\u6211\u4eec <em>\u5f52\u4e00\u5316\uff08normalize\uff09<\/em> \u4e00\u4e2a3D\u5411\u91cf\u4e3a\u5355\u4f4d\u5411\u91cf\u3002<\/p>\n<pre><code class=\"language-js line-numbers\">var a = [ 0, 4, -3 ]\nnormalize(a)\n\/\/=&gt; [ 0, 0.8, -0.6 ]\n<\/code><\/pre>\n<p>\u8fd9\u662f <code>\u5f52\u4e00\u5316\uff08normalize\uff09<\/code> \u51fd\u6570\uff0c\u63a5\u6536\u4e00\u4e2a3D\u5411\u91cf\u53c2\u6570\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function normalize(vec) {\n  var x = vec[0]\n  var y = vec[1]\n  var z = vec[2]\n  var squaredLength = x * x + y * y + z * z\n\n  if (squaredLength &gt; 0) {\n    var length = Math.sqrt(squaredLength)\n    vec[0] = vec[0] \/ length\n    vec[1] = vec[1] \/ length\n    vec[2] = vec[2] \/ length\n  }\n  return vec\n}\n<\/code><\/pre>\n<p>\u5176\u4ed6\u5b9e\u73b0\uff1a<\/p>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-vec3\/blob\/507480fa57ba7c5fb70679cf531175a52c48cf53\/normalize.js\">gl-vec3\/normalize<\/a> \u548c <a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/stackgl\/gl-vec2\/blob\/21f460a371540258521fd2f720d80f14e87bd400\/normalize.js\">gl-vec2\/normalize<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/hughsk\/vectors\/blob\/master\/normalize-nd.js\">vectors\/normalize-nd<\/a> (n-dimensional)<\/li>\n<\/ul>\n<h2>\u5c5e\u4e8e<\/h2>\n<p>\u96c6\u5408\u7406\u8bba\u4e2d\uff0c\u201c\u5c5e\u4e8e\u201d\u7b26\u53f7 <code>\u2208<\/code> \u548c <code>\u220b<\/code> \u53ef\u4ee5\u88ab\u7528\u6765\u63cf\u8ff0\u67d0\u7269\u662f\u5426\u4e3a\u96c6\u5408\u4e2d\u7684\u4e00\u4e2a\u5143\u7d20\u3002\u4f8b\u5982\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?A%3D%5Cleft%20%5C%7B3%2C9%2C14%7D%7B%20%5Cright%20%5C%7D%2C%203%20%5Cin%20A\" alt=\"element1\" \/><\/p>\n<p><!-- A=\\left \\{3,9,14}{  \\right \\}, 3 \\in A --><\/p>\n<p>\u8fd9\u91cc\u6211\u4eec\u6709\u4e00\u4e2a\u6570\u5b57\u96c6 <em>A<\/em> <code>{ 3, 9, 14 }<\/code> \u800c\u4e14\u6211\u4eec\u8bf4 <code>3<\/code> \u662f\u201c\u5c5e\u4e8e\u201d\u8fd9\u4e2a\u96c6\u5408\u7684\u3002<\/p>\n<p>\u5728ES5\u79cd\u4e00\u4e2a\u7b80\u5355\u7684\u5b9e\u73b0\u5e94\u8be5\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var A = [ 3, 9, 14 ]\n\nA.indexOf(3) &gt;= 0\n\/\/=&gt; true\n<\/code><\/pre>\n<p>\u7136\u800c\uff0c\u53ef\u4ee5\u7528\u53ea\u80fd\u4fdd\u5b58\u552f\u4e00\u503c\u7684<code>Set<\/code>\uff0c\u8fd9\u6837\u66f4\u7cbe\u786e\u3002\u8fd9\u662fES6\u7684\u4e00\u4e2a\u7279\u6027\u3002<\/p>\n<pre><code class=\"language-js line-numbers\">var A = new Set([ 3, 9, 14 ])\n\nA.has(3)\n\/\/=&gt; true\n<\/code><\/pre>\n<p>\u53cd\u5411\u7684 <code>\u220b<\/code> \u610f\u4e49\u76f8\u540c\uff0c\u53ea\u662f\u987a\u5e8f\u6539\u53d8\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?A%3D%5Cleft%20%5C%7B3%2C9%2C14%7D%7B%20%5Cright%20%5C%7D%2C%20A%20%5Cni%203\" alt=\"element2\" \/><\/p>\n<p><!-- A=\\left \\{3,9,14}{  \\right \\}, A \\ni 3 --><\/p>\n<p>\u4f60\u53ef\u4ee5\u4f7f\u7528 &#8220;\u4e0d\u5c5e\u4e8e&#8221; \u7b26\u53f7 <code>\u2209<\/code> \u548c <code>\u220c<\/code> \u50cf\u8fd9\u6837\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?A%3D%5Cleft%20%5C%7B3%2C9%2C14%7D%7B%20%5Cright%20%5C%7D%2C%206%20%5Cnotin%20A\" alt=\"element3\" \/><\/p>\n<p><!-- A=\\left \\{3,9,14}{  \\right \\}, 6 \\notin A --><\/p>\n<h2>\u5e38\u89c1\u6570\u5b57\u96c6<\/h2>\n<p>\u4f60\u53ef\u80fd\u5728\u4e00\u4e9b\u516c\u5f0f\u4e2d\u770b\u89c1\u4e00\u4e9b\u5927<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Blackboard_bold\">\u9ed1\u677f\u7c97\u4f53\u5b57<\/a>\u3002\u4ed6\u4eec\u4e00\u822c\u662f\u7528\u6765\u63cf\u8ff0\u96c6\u5408\u7684\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u6211\u4eec\u53ef\u4ee5\u63cf\u8ff0 <em>k<\/em> \u662f<a class=\"wp-editor-md-post-content-link\" href=\"#\u5c5e\u4e8e\">\u5c5e\u4e8e<\/a> <code>\u211d<\/code> \u96c6\u7684\u4e00\u4e2a\u5143\u7d20\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?k%20%5Cin%20%5Cmathbb%7BR%7D\" alt=\"real\" \/><\/p>\n<p><!-- k \\in \\mathbb{R} --><\/p>\n<p>\u4e0b\u8fb9\u5217\u51fa\u4e00\u4e9b\u5e38\u89c1\u96c6\u548c\u4ed6\u4eec\u7684\u7b26\u53f7\u3002<\/p>\n<h4><code>\u211d<\/code> \u5b9e\u6570\uff08real numbers\uff09<\/h4>\n<p>\u5927 <code>\u211d<\/code> \u63cf\u8ff0 <em>\u5b9e\u6570\uff08real numbers\uff09<\/em> \u7684\u96c6\u5408\u3002\u4ed6\u4eec\u5305\u62ec\u6574\u6570\uff0c\u6709\u7406\u6570\uff0c\u65e0\u7406\u6570\u3002<\/p>\n<p>JavaScript\u8ba4\u4e3a\u6574\u6570\u548c\u6d6e\u70b9\u6570\u4e3a\u76f8\u540c\u7c7b\u578b\uff0c\u6240\u4ee5\u4e0b\u8fb9\u5c06\u662f\u4e00\u4e2a <em>k<\/em> \u2208 \u211d \u7684\u7b80\u5355\u6d4b\u8bd5\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function isReal (k) {\n  return typeof k === 'number' &amp;&amp; isFinite(k);\n}\n<\/code><\/pre>\n<p><em>\u6ce8\u610f\uff1a<\/em> \u5b9e\u6570\u4e5f\u662f <em>\u6709\u9650\u6570\uff08finite\uff09<\/em>\uff0c<em>\u975e\u65e0\u9650\u7684\uff08not infinite\uff09<\/em><\/p>\n<h4><code>\u211a<\/code> \u6709\u7406\u6570\uff08rational numbers\uff09<\/h4>\n<p>\u6709\u7406\u6570\u662f\u53ef\u4ee5\u88ab\u8868\u793a\u4e3a\u5206\u6570\uff0c\u6216 <em>\u6bd4\u7387<\/em>\uff08\u7c7b\u4f3c<code>\u2157<\/code>\uff09\u7684\u5b9e\u6570\u3002\u6709\u7406\u6570\u4e0d\u80fd\u4ee50\u4f5c\u5206\u6bcd\u3002<\/p>\n<p>\u8fd9\u610f\u5473\u7740\u6240\u6709\u7684\u6574\u6570\u90fd\u662f\u6709\u7406\u6570\uff0c\u56e0\u4e3a\u53ef\u4ee5\u770b\u6210\u5206\u6bcd\u4e3a1\u3002<\/p>\n<p>\u6362\u53e5\u8bdd\u8bf4\u65e0\u7406\u6570\u5c31\u662f\u4e0d\u80fd\u8868\u793a\u4e3a\u6bd4\u7387\u7684\u6570\uff0c\u4f8b\u5982 \u03c0 (PI)\u3002<\/p>\n<h4><code>\u2124<\/code> \u6574\u6570\uff08integers\uff09<\/h4>\n<p>\u4e00\u4e2a\u6574\u6570\uff0c\u662f\u6ca1\u6709\u5c0f\u6570\u90e8\u5206\u7684\u5b9e\u6570\u3002\u53ef\u4e3a\u6b63\u4e5f\u53ef\u4ee5\u4e3a\u8d1f\u3002<\/p>\n<p>\u5728JavaScript\u4e2d\u7684\u7b80\u5355\u6d4b\u8bd5\u5e94\u8be5\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function isInteger (n) {\n  return typeof n === 'number' &amp;&amp; n % 1 === 0\n}\n<\/code><\/pre>\n<h4><code>\u2115<\/code> \u81ea\u7136\u6570\uff08natural numbers\uff09<\/h4>\n<p>\u81ea\u7136\u6570\u662f\u6b63\u6574\u6570\u6216\u975e\u8d1f\u6574\u6570\u3002\u53d6\u51b3\u4e8e\u6240\u5b66\u9886\u57df\u548c\u4e0a\u4e0b\u6587\uff0c\u96c6\u5408\u4e2d\u53ef\u80fd\u5305\u542b\u4e5f\u53ef\u80fd\u4e0d\u5305\u542b0\uff0c\u6240\u4ee5\u53ef\u4ee5\u662f\u4e0b\u8fb9\u4efb\u610f\u4e00\u79cd\u96c6\u5408\u3002<\/p>\n<pre><code class=\"language-js line-numbers\">{ 0, 1, 2, 3, ... }\n{ 1, 2, 3, 4, ... }\n<\/code><\/pre>\n<p>\u524d\u8005\u5728\u8ba1\u7b97\u673a\u79d1\u5b66\u4e2d\u66f4\u5e38\u89c1\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function isNaturalNumber (n) {\n  return isInteger(n) &amp;&amp; n &gt;= 0\n}\n<\/code><\/pre>\n<h4><code>\u2102<\/code> \u590d\u6570<\/h4>\n<p>\u590d\u6570\u662f\u5b9e\u6570\u4e0e\u865a\u6570\u7684\u7ec4\u5408\uff0c\u88ab\u89c6\u4e3a2D\u5e73\u9762\u4e0a\u7684\u4e00\u4e2a\u5750\u6807\u3002\u66f4\u8be6\u7ec6\u7684\u4fe1\u606f\u8bf7\u770b<a class=\"wp-editor-md-post-content-link\" href=\"http:\/\/betterexplained.com\/articles\/a-visual-intuitive-guide-to-imaginary-numbers\/\">A Visual, Intuitive Guide to Imaginary Numbers<\/a>\u3002<\/p>\n<h2>\u51fd\u6570<\/h2>\n<p><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Function_%28mathematics%29\">\u51fd\u6570<\/a> \u662f\u6570\u5b66\u7684\u57fa\u672c\u7279\u6027\uff0c\u5176\u6982\u5ff5\u5f88\u5bb9\u6613\u8f6c\u6362\u6210\u4ee3\u7801\u3002<\/p>\n<p>\u51fd\u6570\u628a\u8f93\u5165\u8f93\u51fa\u503c\u8054\u7cfb\u8d77\u6765\u3002\u4f8b\u5982\u4e0b\u8fb9\u662f\u4e00\u4e2a\u51fd\u6570\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?x%5E%7B2%7D\" alt=\"function1\" \/><\/p>\n<p><!-- x^{2} --><\/p>\n<p>\u6211\u4eec\u53ef\u4ee5\u7ed9\u51fd\u6570\u4e00\u4e2a <em>\u540d\u5b57<\/em> \u3002\u4e00\u822c\u6765\u8bf4\u6211\u4eec\u7528  <code>\u0192<\/code> \u6765\u63cf\u8ff0\u4e00\u4e2a\u51fd\u6570\uff0c\u4f46\u4e5f\u53ef\u4ee5\u547d\u540d\u4e3a <code>A(x)<\/code> \u6216\u5176\u4ed6\u4ec0\u4e48\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?f%5Cleft%20%28x%20%5Cright%20%29%20%3D%20x%5E%7B2%7D\" alt=\"function2\" \/><\/p>\n<p><!-- f\\left (x  \\right ) = x^{2} --><\/p>\n<p>\u5728\u4ee3\u7801\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u7ed9\u51fd\u6570\u547d\u540d\u4e3a <code>square<\/code> \u5199\u51fa\u6765\u5e94\u8be5\u7c7b\u4f3c\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function square (x) {\n  return Math.pow(x, 2)\n}\n<\/code><\/pre>\n<p>\u6709\u65f6\u51fd\u6570\u6ca1\u6709\u540d\u5b57\uff0c\u800c\u662f\u76f4\u63a5\u5199\u51fa\u8f93\u51fa\u503c\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?y%20%3D%20x%5E%7B2%7D\" alt=\"function3\" \/><\/p>\n<p><!-- y = x^{2} --><\/p>\n<p>\u5728\u4e0a\u8fb9\u7684\u4f8b\u5b50\u4e2d\uff0c<em>x<\/em> \u662f\u8f93\u5165\u503c\uff0c<em>y<\/em> \u662f\u8f93\u51fa\u503c\uff0c\u4ed6\u4eec\u662f\u5e73\u65b9\u7684\u5173\u7cfb\u3002<\/p>\n<p>\u50cf\u7f16\u7a0b\u8bed\u8a00\u4e00\u6837\uff0c\u51fd\u6570\u4e5f\u53ef\u4ee5\u6709\u591a\u4e2a\u53c2\u6570\u3002\u4ed6\u4eec\u5728\u6570\u5b66\u4e2d\u88ab\u79f0\u4e3a <em>arguments<\/em>\uff0c\u5e76\u4e14\u51fd\u6570\u63a5\u53d7\u7684\u53c2\u6570\u6570\u91cf\u88ab\u79f0\u4e3a\u51fd\u6570\u7684 <em>arity<\/em> \u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?f%28x%2Cy%29%20%3D%20%5Csqrt%7Bx%5E2%20&plus;%20y%5E2%7D\" alt=\"function4\" \/><\/p>\n<p><!-- f(x,y) = \\sqrt{x^2 + y^2} --><\/p>\n<p>\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function length (x, y) {\n  return Math.sqrt(x * x + y * y)\n}\n<\/code><\/pre>\n<h3>\u5206\u6bb5\u51fd\u6570<\/h3>\n<p>\u6709\u4e9b\u51fd\u6570\u6839\u636e\u8f93\u5165\u503c <em>x<\/em> \u7684\u4e0d\u540c\u4f1a\u6709\u4e0d\u540c\u7684\u5173\u7cfb\u3002<\/p>\n<p>\u4e0b\u8fb9\u7684\u51fd\u6570 <em>f<\/em> \u6839\u636e\u4e0d\u540c\u7684\u8f93\u5165\u503c\u9009\u62e9\u4e24\u4e2a\u4e0d\u540c\u7684\u201c\u5b50\u51fd\u6570\u201d\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?f%28x%29%3D%20%5Cbegin%7Bcases%7D%20%5Cfrac%7Bx%5E2-x%7D%7Bx%7D%2C%26%20%5Ctext%7Bif%20%7D%20x%5Cgeq%201%5C%5C%200%2C%20%26%20%5Ctext%7Botherwise%7D%20%5Cend%7Bcases%7D\" alt=\"piecewise1\" \/><\/p>\n<p><!--    f(x)= \n\\begin{cases}\n    \\frac{x^2-x}{x},& \\text{if } x\\geq 1\\\\\n    0, & \\text{otherwise}\n\\end{cases} --><\/p>\n<p>\u8fd9\u975e\u5e38\u63a5\u8fd1\u4e8e\u4ee3\u7801\u4e2d\u7684<code>if<\/code> \/ <code>else<\/code>\u3002\u53f3\u8fb9\u7684\u6761\u4ef6\u7ecf\u5e38\u88ab\u5199\u4e3a<strong>&#8220;for x &lt; 0&#8221;<\/strong> \u6216 <strong>&#8220;if x = 0&#8221;<\/strong>\u3002\u5982\u679c\u6761\u4ef6\u4e3atrue\uff0c\u5c31\u4f7f\u7528\u5176\u5de6\u8fb9\u7684\u51fd\u6570\u3002<\/p>\n<p>\u5728\u5206\u6bb5\u51fd\u6570\u4e2d\uff0c<strong>&#8220;otherwise&#8221;<\/strong> \u548c <strong>&#8220;elsewhere&#8221;<\/strong> \u7c7b\u4f3c\u4e8e\u4ee3\u7801\u4e2d\u7684 <code>else<\/code> \u3002<\/p>\n<pre><code class=\"language-js line-numbers\">function f (x) {\n  if (x &gt;= 1) {\n    return (Math.pow(x, 2) - x) \/ x\n  } else {\n    return 0\n  }\n}\n<\/code><\/pre>\n<h3>\u901a\u7528\u51fd\u6570<\/h3>\n<p>\u6709\u4e9b\u51fd\u6570\u540d\u5728\u6570\u5b66\u4e2d\u662f\u666e\u904d\u5b58\u5728\u7684\u3002\u5728\u4e00\u4e2a\u7a0b\u5e8f\u5458\u7684\u89d2\u5ea6\u770b\uff0c\u8fd9\u4e9b\u5e94\u8be5\u7c7b\u4f3c\u4e8e\u7f16\u7a0b\u8bed\u8a00\u4e2d\u7684\u201c\u5185\u7f6e\u201d\u51fd\u6570\uff08\u5c31\u50cfJavaScript\u4e2d\u7684 <code>parseInt<\/code> \uff09\u3002<\/p>\n<p>\u4e00\u4e2a\u4f8b\u5b50\u5c31\u662f <em>sgn<\/em> \u51fd\u6570\u3002\u8fd9\u662f <em>\u6b63\u8d1f\u53f7<\/em> \u51fd\u6570\uff0c\u6216\u8005\u53eb <em>\u7b26\u53f7<\/em> \u51fd\u6570\u3002\u8ba9\u6211\u4eec\u7528<a class=\"wp-editor-md-post-content-link\" href=\"#\u5206\u6bb5\u51fd\u6570\">\u5206\u6bb5\u51fd\u6570<\/a>\u6765\u63cf\u8ff0\u5b83\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?sgn%28x%29%20%3A%3D%20%5Cbegin%7Bcases%7D%20-1%26%20%5Ctext%7Bif%20%7D%20x%20%3C%200%5C%5C%200%2C%20%26%20%5Ctext%7Bif%20%7D%20%7Bx%20%3D%200%7D%5C%5C%201%2C%20%26%20%5Ctext%7Bif%20%7D%20x%20%3E%200%5C%5C%20%5Cend%7Bcases%7D\" alt=\"sgn\" \/><\/p>\n<p><!-- sgn(x) := \n\\begin{cases}\n    -1& \\text{if } x < 0\\\\\n    0, & \\text{if } {x = 0}\\\\\n    1, & \\text{if } x > 0\\\\\n\\end{cases} --><\/p>\n<p>\u4ee3\u7801\u4e2d\uff0c\u5e94\u8be5\u8fd9\u6837\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function sgn (x) {\n  if (x &lt; 0) return -1\n  if (x &gt; 0) return 1\n  return 0\n}\n<\/code><\/pre>\n<p>\u6b64\u51fd\u6570\u4f5c\u4e3a\u72ec\u7acb\u7684module\u5728\u8fd9\u91cc<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/scijs\/signum\">signum<\/a>\u3002<\/p>\n<p>\u5176\u4ed6\u7c7b\u4f3c\u51fd\u6570\u7684\u4f8b\u5b50\u8fd8\u6709: <em>sin<\/em>\uff0c <em>cos<\/em>\uff0c <em>tan<\/em>\u3002<\/p>\n<h3>\u51fd\u6570\u7b26\u53f7<\/h3>\n<p>\u5728\u67d0\u4e9b\u8457\u4f5c\u4e2d\uff0c\u51fd\u6570\u53ef\u4ee5\u88ab\u66f4\u660e\u786e\u7684\u7b26\u53f7\u5b9a\u4e49\u3002\u4f8b\u5982\uff0c\u8ba9\u6211\u4eec\u56de\u5230\u4e4b\u524d\u63d0\u5230\u7684 <code>square<\/code> \u51fd\u6570\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?f%5Cleft%20%28x%20%5Cright%20%29%20%3D%20x%5E%7B2%7D\" alt=\"function2\" \/><\/p>\n<p><!-- f\\left (x  \\right ) = x^{2} --><\/p>\n<p>\u4e5f\u53ef\u4ee5\u5199\u4e3a\u4ee5\u4e0b\u5f62\u5f0f\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?f%20%3A%20x%20%5Cmapsto%20x%5E2\" alt=\"mapsto\" \/><\/p>\n<p><!-- f : x \\mapsto x^2 --><\/p>\n<p>\u5e26\u5c3e\u5df4\u7684\u7bad\u5934\u901a\u5e38\u610f\u601d\u4e3a\u201c\u6620\u5c04\u5230\u201d\uff0c\u5982\uff0c<em>\u5c06x\u6620\u5c04\u5230x<sup>2<\/sup><\/em><\/p>\n<p>\u6709\u65f6\uff0c\u4e0d\u662f\u5f88\u5e38\u89c1\uff0c\u8fd9\u4e2a\u7b26\u53f7\u4e5f\u7528\u6765\u63cf\u8ff0\u51fd\u6570\u7684 <em>domain<\/em> \u548c <em>codomain<\/em>\u3002\u5bf9 <em>\u0192<\/em> \u66f4\u6b63\u5f0f\u7684\u5b9a\u4e49\u53ef\u4ee5\u5199\u4e3a\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5Cbegin%7Balign*%7D%20f%20%3A%26%5Cmathbb%7BR%7D%20%5Crightarrow%20%5Cmathbb%7BR%7D%5C%5C%20%26x%20%5Cmapsto%20x%5E2%20%5Cend%7Balign*%7D\" alt=\"funcnot\" \/><\/p>\n<p><!-- \\begin{align*}\nf :&\\mathbb{R} \\rightarrow \\mathbb{R}\\\\\n&x \\mapsto x^2 \n\\end{align*}\n --><\/p>\n<p>\u51fd\u6570\u7684 <em>domain<\/em> \u548c <em>codomain<\/em> \u5206\u522b\u8ddf\u4ed6\u7684 <em>input<\/em> \u548c <em>output<\/em> \u7c7b\u578b\u6709\u70b9\u50cf\u3002\u8fd9\u91cc\u6709\u53e6\u4e00\u4e2a\u4f8b\u5b50\uff0c\u4f7f\u7528\u4e86\u6211\u4eec\u4e4b\u524d\u8f93\u51fa\u6574\u6570\u7684 <em>sgn<\/em> \u51fd\u6570\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?sgn%20%3A%20%5Cmathbb%7BR%7D%20%5Crightarrow%20%5Cmathbb%7BZ%7D\" alt=\"domain2\" \/><\/p>\n<p><!-- sgn : \\mathbb{R} \\rightarrow \\mathbb{Z} --><\/p>\n<p>\u8fd9\u91cc\u7684\u7bad\u5934\uff08\u6ca1\u6709\u5c3e\u5df4\uff09\u7528\u6765\u6620\u5c04\u4e00\u4e2a <em>\u96c6\u5408<\/em> \u5230\u53e6\u4e00\u4e2a\u3002<\/p>\n<p>\u5728JavaScript\u548c\u5176\u4ed6\u52a8\u6001\u7c7b\u578b\u8bed\u8a00\u4e2d\uff0c\u4f60\u4e5f\u8bb8\u4f1a\u7528\u6587\u6863 \u548c\/\u6216 \u8fd0\u884c\u65f6\u68c0\u67e5\u6765\u89e3\u91ca\u548c\u9a8c\u8bc1\u51fd\u6570\u7684\u8f93\u5165\/\u8f93\u51fa\u3002\u4f8b\u5b50\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">\/**\n * Squares a number.\n * @param  {Number} a real number\n * @return {Number} a real number\n *\/\nfunction square (a) {\n  if (typeof a !== 'number') {\n    throw new TypeError('expected a number')\n  }\n  return Math.pow(a, 2)\n}\n<\/code><\/pre>\n<p>\u6709\u4e9b\u5de5\u5177\u4f8b\u5982<a class=\"wp-editor-md-post-content-link\" href=\"http:\/\/flowtype.org\/\">flowtype<\/a>\u5c1d\u8bd5\u5c06\u9759\u6001\u7c7b\u578b\u5e26\u5165\u5230JavaScript\u4e2d\u3002<\/p>\n<p>\u5176\u4ed6\u8bed\u8a00\uff0c\u4f8b\u5982Java\uff0c\u5141\u8bb8\u771f\u6b63\u7684\u65b9\u6cd5\u91cd\u8f7d\uff08overloading\uff09\uff0c\u5b83\u4eec\u57fa\u4e8e\u51fd\u6570\u8f93\u5165\u8f93\u51fa\u7684\u9759\u6001\u7c7b\u578b\u3002\u8fd9\u66f4\u63a5\u8fd1\u4e8e\u6570\u5b66\u9886\u57df\uff1a\u4f7f\u7528\u4e0d\u540c <em>domain<\/em> \u7684\u4e24\u4e2a\u51fd\u6570\u662f\u4e0d\u540c\u7684\u3002<\/p>\n<h2>\u6487\u53f7\uff08prime\uff09<\/h2>\n<p>\u6487\u53f7 (<code>\u2032<\/code>) \u901a\u5e38\u7528\u5728\u53d8\u91cf\u540d\u4e0a\uff0c\u7528\u6765\u63cf\u8ff0\u67d0\u7269\u5f88\u7c7b\u4f3c\uff0c\u800c\u4e0d\u7528\u53e6\u8d77\u4e2a\u540d\u6765\u63cf\u8ff0\u5b83\u3002\u4e5f\u53ef\u4ee5\u63cf\u8ff0\u7ecf\u8fc7\u4e00\u4e9b\u53d8\u6362\u540e\u7684\u201c\u4e0b\u4e00\u4e2a\u503c\u201d\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u5982\u679c\u6211\u4eec\u6709\u4e00\u4e2a2D\u70b9 <em>(x, y)<\/em> \uff0c\u7136\u540e\u65cb\u8f6c\u5b83\uff0c\u4f60\u4f1a\u628a\u65cb\u8f6c\u540e\u7684\u70b9\u547d\u540d\u4e3a<em>(x\u2032, y\u2032)<\/em>\u3002 \u6216\u8005\u5c06\u77e9\u9635 <strong>M<\/strong> \u7684 <em>\u8f6c\u7f6e\u77e9\u9635<\/em> \u547d\u540d\u4e3a <strong>M\u2032<\/strong>\u3002<\/p>\n<p>\u5728\u4ee3\u7801\u4e2d\uff0c\u6211\u4eec\u901a\u5e38\u7684\u5206\u914d\u4e00\u4e2a\u63cf\u8ff0\u66f4\u8be6\u7ec6\u7684\u53d8\u91cf\u540d\uff0c\u4f8b\u5982<code>transformedPosition<\/code>\u3002<\/p>\n<p>\u5bf9\u4e8e\u4e00\u4e2a<a class=\"wp-editor-md-post-content-link\" href=\"#\u51fd\u6570\">\u51fd\u6570<\/a>\uff0c\u6487\u53f7\u901a\u5e38\u63cf\u8ff0\u4e3a\u51fd\u6570\u7684 <em>\u5bfc\u51fd\u6570\uff08derivative\uff09<\/em> \u3002\u5bfc\u51fd\u6570\u4f1a\u5728\u672a\u6765\u7684\u7ae0\u8282\u89e3\u91ca\u3002\u6211\u4eec\u6765\u770b\u4e00\u4e2a\u4e4b\u524d\u7684\u51fd\u6570\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?f%5Cleft%20%28x%20%5Cright%20%29%20%3D%20x%5E%7B2%7D\" alt=\"function2\" \/><\/p>\n<p><!-- f\\left (x  \\right ) = x^{2} --><\/p>\n<p>\u5b83\u7684\u5bfc\u51fd\u6570\uff08derivative\uff09\u53ef\u4ee5\u5199\u4e3a\u4e00\u4e2a\u5e26\u6487\u53f7<code>\u2032<\/code>\u7684\u51fd\u6570\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?f%27%28x%29%20%3D%202x\" alt=\"prime1\" \/><\/p>\n<p><!-- f'(x) = 2x --><\/p>\n<p>\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">function f (x) {\n  return Math.pow(x, 2)\n}\n\nfunction fPrime (x) {\n  return 2 * x\n}\n<\/code><\/pre>\n<p>\u4f7f\u7528\u591a\u4e2a\u6487\u53f7\u53ef\u4ee5\u7528\u6765\u8868\u793a \u4e8c\u9636\u5bfc\u51fd\u6570\uff08derivative\uff09 <em>\u0192\u2032\u2032<\/em> \u6216 \u4e09\u9636\u5bfc\u51fd\u6570\uff08derivative\uff09<em>\u0192\u2032\u2032\u2032<\/em> \uff0c\u4e4b\u540e\u66f4\u9ad8\u7684\u6570\u5b57\uff0c\u4e00\u822c\u4f5c\u8005\u4f1a\u7528\u7f57\u9a6c\u6570\u5b57 <em>\u0192<\/em><sup>IV<\/sup> \u6216\u4e0a\u6807\u6570\u5b57 <em>\u0192<\/em><sup>(n)<\/sup> \u8868\u793a\u3002<\/p>\n<h2>\u5411\u4e0b\u53d6\u6574\u548c\u5411\u4e0a\u53d6\u6574\uff08floor &amp; ceiling\uff09<\/h2>\n<p><code>\u230ax\u230b<\/code> \u548c <code>\u2308x\u2309<\/code> \u8fd9\u79cd\u7279\u6b8a\u7684\u62ec\u53f7\u5206\u522b\u7528\u6765\u8868\u793a<em>floor<\/em> \u548c <em>ceil<\/em> \u51fd\u6570\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?floor%28x%29%20%3D%20%5Clfloor%20x%20%5Crfloor\" alt=\"floor\" \/><\/p>\n<p><!-- floor(x) =  \\lfloor x \\rfloor --><\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?ceil%28x%29%20%3D%20%5Clceil%20x%20%5Crceil\" alt=\"ceil\" \/><\/p>\n<p><!-- ceil(x) =  \\lceil x \\rceil --><\/p>\n<p>\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">Math.floor(x)\nMath.ceil(x)\n<\/code><\/pre>\n<p>\u5f53\u8fd9\u4e24\u4e2a\u7b26\u53f7\u6df7\u5408<code>\u230ax\u2309<\/code>\uff0c\u5b83\u901a\u5e38\u8868\u793a\u4e00\u4e2a\u53d6\u6574\u5230\u6700\u8fd1\u7684\u6574\u6570\u7684\u51fd\u6570\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?round%28x%29%20%3D%20%5Clfloor%20x%20%5Crceil\" alt=\"round\" \/><\/p>\n<p><!-- round(x) =  \\lfloor x \\rceil --><\/p>\n<p>\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">Math.round(x)\n<\/code><\/pre>\n<h2>\u7bad\u5934<\/h2>\n<p>\u7bad\u5934\u901a\u5e38\u7528\u6765\u8868\u793a<a class=\"wp-editor-md-post-content-link\" href=\"#\u51fd\u6570\u7b26\u53f7\">\u51fd\u6570\u7b26\u53f7<\/a>\u3002\u8fd9\u91cc\u8fd8\u6709\u4e00\u4e9b\u5728\u5176\u4ed6\u9886\u57df\u4e2d\u7684\u7528\u6cd5\u53ef\u4ee5\u770b\u770b\u3002<\/p>\n<h4>\u5b9e\u8d28\u8574\u542b\uff08material implication\uff09<\/h4>\n<p><code>\u21d2<\/code> \u548c <code>\u2192<\/code> \u4f18\u52bf\u88ab\u7528\u4f5c\u8868\u793a\u5b9e\u8d28\u8574\u6db5\uff08material implication\uff09\u7684\u903b\u8f91\u3002\u610f\u601d\u662f\u5982\u679cA\u662ftrue\uff0c\u90a3\u4e48B\u4e5f\u662ftrue\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?A%20%5CRightarrow%20B\" alt=\"material1\" \/><\/p>\n<p><!-- A \\Rightarrow B --><\/p>\n<p>\u89e3\u91ca\u4e3a\u4ee3\u7801\u5e94\u8be5\u4e3a\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">if (A === true) {\n  console.assert(B === true)\n}\n<\/code><\/pre>\n<p>\u7bad\u5934\u53ef\u4ee5\u662f\u5de6\u53f3\u4efb\u4f55\u65b9\u5411 <code>\u21d0<\/code> <code>\u21d2<\/code>\uff0c\u4e5f\u53ef\u4ee5\u53cc\u5411<code>\u21d4<\/code>\u3002\u5f53 <em>A \u21d2 B<\/em> \u5e76\u4e14 <em>B \u21d2 A<\/em>\uff0c\u5c31\u662f\u4ed6\u4eec\u662f\u76f8\u7b49\u7684\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?A%20%5CLeftrightarrow%20B\" alt=\"material-equiv\" \/><\/p>\n<p><!-- A \\Leftrightarrow B --><\/p>\n<h4>\u7b49\u5f0f\uff08equality\uff09<\/h4>\n<p>\u5728\u6570\u5b66\u4e2d\uff0c <code>&lt;<\/code> <code>&gt;<\/code> <code>\u2264<\/code> \u548c <code>\u2265<\/code> \u4e0e\u4ee3\u7801\u4e2d\u7684\u4f7f\u7528\u65b9\u6cd5\u4e00\u6837\uff1a\u5206\u522b\u4e3a <em>\u5c0f\u4e8e<\/em>, <em>\u5927\u4e8e<\/em>, <em>\u5c0f\u4e8e\u7b49\u4e8e<\/em> \u548c <em>\u5927\u4e8e\u7b49\u4e8e<\/em>\u3002<\/p>\n<pre><code class=\"language-js line-numbers\">50 &gt; 2 === true\n2 &lt; 10 === true\n3 &lt;= 4 === true\n4 &gt;= 4 === true\n<\/code><\/pre>\n<p>\u5076\u5c14\u4f1a\u770b\u5230\u5728\u8fd9\u4e9b\u7b26\u53f7\u4e0a\u52a0\u4e86\u4e00\u6761\u659c\u7ebf\uff0c\u6765\u8868\u793a <em>\u4e0d<\/em>\uff0c\u6bd4\u5982\uff0c <em>k<\/em> \u4e0d &#8220;\u5927\u4e8e&#8221; <em>j<\/em>.<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?k%20%5Cngtr%20j\" alt=\"ngt\" \/><\/p>\n<p><!-- k \\ngtr j --><\/p>\n<p><code>\u226a<\/code> \u548c <code>\u226b<\/code>\u901a\u5e38\u7528\u6765\u8868\u793a <em>\u660e\u663e\uff08significant\uff09<\/em> \u4e0d\u76f8\u7b49\u3002\u8fd9\u662f\u8bf4 <em>k<\/em> \u662f\u6709<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/en.wikipedia.org\/wiki\/Order_of_magnitude\">\u6570\u91cf\u7ea7\uff08order of magnitude\uff09<\/a>\u7684\u5927\u4e8e <em>j<\/em>\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?k%20%5Cgg%20j\" alt=\"orderofmag\" \/><\/p>\n<p><!-- k \\gg j --><\/p>\n<p>\u5728\u6570\u5b66\u4e2d\uff0c<em>\u6570\u91cf\u7ea7\uff08order of magnitude\uff09<\/em> \u662f\u76f8\u5f53\u660e\u786e\u7684\uff1b\u4e0d\u53ea\u662f\u201c\u76f8\u5f53\u5927\u7684\u4e0d\u540c\u201d\u800c\u5df2\u3002\u4e0a\u8fb9\u7684\u4e00\u4e2a\u7b80\u5355\u4f8b\u5b50\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">orderOfMagnitude(k) &gt; orderOfMagnitude(j)\n<\/code><\/pre>\n<p>\u4e0b\u8fb9\u662f\u6211\u4eec\u7684 <code>orderOfMagnitude<\/code> \u51fd\u6570\uff0c\u4f7f\u7528\u4e86<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/developer.mozilla.org\/en-US\/docs\/Web\/JavaScript\/Reference\/Global_Objects\/Math\/trunc\">Math.trunc<\/a> (ES6)\u3002<\/p>\n<pre><code class=\"language-js line-numbers\">function log10(n) {\n  \/\/ logarithm in base 10\n  return Math.log(n) \/ Math.LN10\n}\n\nfunction orderOfMagnitude (n) {\n  return Math.trunc(log10(n))\n}\n<\/code><\/pre>\n<p><sup><em>Note:<\/em> This is not numerically robust.<\/sup><\/p>\n<p>\u8fd9\u91cc\u662f\u5728ES5\u4e0b\u4f7f\u7528<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/www.npmjs.com\/package\/math-trunc\">math-trunc<\/a> \u7684polyfill\u3002<\/p>\n<h4>\u4e0e\uff08conjunction\uff09 &amp; \u6216\uff08disjunction\uff09<\/h4>\n<p>\u53e6\u4e00\u79cd\u7bad\u5934\u5728\u903b\u8f91\u4e2d\u7684\u4f7f\u7528\u662f\u4e0e\uff08conjunction\uff09<code>\u2227<\/code> \u548c \u6216\uff08disjunction\uff09 <code>\u2228<\/code>\u3002\u4ed6\u4eec\u5206\u522b\u7c7b\u4f3c\u4e8e\u7a0b\u5e8f\u5458\u7684 <code>AND<\/code> \u548c <code>OR<\/code>\u64cd\u4f5c\u3002<\/p>\n<p>\u4e0b\u8fb9\u5c55\u793a\u4e86\u4e0e\uff08conjunction\uff09<code>\u2227<\/code>\uff0c \u903b\u8f91\u4e2d\u7684<code>AND<\/code>.<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?k%20%3E%202%20%5Cland%20k%20%3C%204%20%5CLeftrightarrow%20k%20%3D%203\" alt=\"and\" \/><\/p>\n<p><!-- k > 2 \\land k <  4 \\Leftrightarrow k = 3   --><\/p>\n<p>\u5728JavaScript\u4e2d\uff0c\u6211\u4eec\u4f7f\u7528 <code>&amp;&amp;<\/code> \u5047\u8bbe <em>k<\/em> \u662f\u4e00\u4e2a\u81ea\u7136\u6570\uff0c\u90a3\u4e48\u8fd9\u4e2a\u903b\u8f91\u610f\u5473\u7740k\u7b49\u4e8e3\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">if (k &gt; 2 &amp;&amp; k &lt; 4) {\n  console.assert(k === 3)\n}\n<\/code><\/pre>\n<p>\u7531\u4e8e\u53cc\u8fb9\u90fd\u76f8\u7b49 <code>\u21d4<\/code>\uff0c\u6240\u4ee5\u4e5f\u8bf4\u660e\u4e0b\u8fb9\u6210\u7acb\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">if (k === 3) {\n  console.assert(k &gt; 2 &amp;&amp; k &lt; 4)\n}\n<\/code><\/pre>\n<p>\u4e0b\u7bad\u5934 <code>\u2228<\/code> \u662f\u903b\u8f91\u6216\uff08disjunction\uff09\uff0c\u5c31\u50cf OR \u64cd\u4f5c\u7b26\u4e00\u6837\u3002<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?A%20%5Clor%20B\" alt=\"logic-or\" \/><\/p>\n<p><!-- A \\lor B --><\/p>\n<p>\u4ee3\u7801\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">A || B\n<\/code><\/pre>\n<h2>\u903b\u8f91\u975e\uff08logical negation\uff09<\/h2>\n<p>\u6709\u65f6\u5019\uff0c<code>\u00ac<\/code>, <code>~<\/code> \u548c <code>!<\/code> \u7b26\u53f7\u90fd\u7528\u6765\u8868\u793a\u903b\u8f91 <code>NOT<\/code>\u3002\u4f8b\u5982\uff0c\u53ea\u6709\u5728A\u4e3afalse\u7684\u65f6\u5019\uff0c<em>\u00acA<\/em> \u4e3atrue\u3002<\/p>\n<p>\u8fd9\u91cc\u662f\u4e00\u4e2a\u4f7f\u7528 <em>not<\/em> \u7b26\u53f7\u7b80\u5355\u7684\u4f8b\u5b50\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?x%20%5Cneq%20y%20%5CLeftrightarrow%20%5Clnot%28x%20%3D%20y%29\" alt=\"negation\" \/><\/p>\n<p><!-- x \\neq y \\Leftrightarrow \\lnot(x = y) --><\/p>\n<p>\u7ffb\u8bd1\u6210\u4ee3\u7801\u7684\u4f8b\u5b50\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">if (x !== y) {\n  console.assert(!(x === y))\n}\n<\/code><\/pre>\n<p><em>\u6ce8\u610f\uff1a<\/em> \u6839\u636e\u4e0a\u4e0b\u6587\u7684\u4e0d\u540c\uff0c\u6ce2\u6d6a\u7ebf <code>~<\/code> \u53ef\u4ee5\u6709\u5f88\u591a\u79cd\u4e0d\u540c\u7684\u610f\u601d\u3002\u4f8b\u5982\uff0c<em>\u884c\u7b49\u4ef7\uff08row equivalence\uff09<\/em>\uff08\u77e9\u9635\u7406\u8bba\uff09\u6216<em>\u76f8\u540c\u6570\u91cf\u7ea7\uff08same order of magnitude\uff09<\/em> \uff08\u5728<a class=\"wp-editor-md-post-content-link\" href=\"#\u7b49\u5f0fequality\">\u7b49\u5f0f\uff08equality\uff09<\/a>\u7ae0\u8282\u8ba8\u8bba\u8fc7\uff09\u3002<\/p>\n<h2>\u533a\u95f4\uff08intervals\uff09<\/h2>\n<p>\u6709\u65f6\u51fd\u6570\u4f1a\u5904\u7406\u88ab\u4e00\u4e9b\u503c\u9650\u5b9a\u8303\u56f4\u7684\u5b9e\u6570\uff0c\u8fd9\u6837\u7684\u7ea6\u675f\u53ef\u4ee5\u7528<em>\u533a\u95f4\uff08interval\uff09<\/em>\u6765\u8868\u793a\u3002<\/p>\n<p>\u4f8b\u5982\u6211\u4eec\u53ef\u4ee5\u8868\u793a0\u548c1\u4e4b\u95f4\u7684\u6570\uff0c\u8ba9\u4ed6\u4eec\u5305\u542b\u6216\u4e0d\u5305\u542b0\u548c1\uff1a<\/p>\n<ul>\n<li>\u4e0d\u5305\u542b0\u62161\uff1a <img src=\"http:\/\/latex.codecogs.com\/svg.latex?%280%2C%201%29\" alt=\"interval-opened-left-opened-right\" \/><\/li>\n<\/ul>\n<p><!-- (0, 1) --><\/p>\n<ul>\n<li>\u5305\u542b0\u4f46\u4e0d\u5305\u542b1\uff1a <img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5B0%2C%201%29\" alt=\"interval-closed-left-opened-right\" \/><\/li>\n<\/ul>\n<p><!-- [0, 1) --><\/p>\n<ul>\n<li>\u4e0d\u5305\u542b0\u4f46\u5305\u542b1\uff1a <img src=\"http:\/\/latex.codecogs.com\/svg.latex?%280%2C%201%5D\" alt=\"interval-opened-left-closed-right\" \/><\/li>\n<\/ul>\n<p><!-- (0, 1] --><\/p>\n<ul>\n<li>\u5305\u542b0\u548c1\uff1a <img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5B0%2C%201%5D\" alt=\"interval-closed-left-closed-right\" \/><\/li>\n<\/ul>\n<p><!-- [0, 1] --><\/p>\n<p>\u4f8b\u5982\u6211\u4eec\u6307\u51fa\u4e00\u4e2a\u70b9 <code>x<\/code> \u57283D\u5355\u4f4d\u7acb\u65b9\u4f53\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u8bf4\uff1a<\/p>\n<p><img src=\"http:\/\/latex.codecogs.com\/svg.latex?x%20%5Cin%20%5B0%2C%201%5D%5E3\" alt=\"interval-unit-cube\" \/><\/p>\n<p><!-- x \\in [0, 1]^3 --><\/p>\n<p>\u5728\u4ee3\u7801\u4e2d\u6211\u4eec\u53ef\u4ee5\u7528\u4e24\u4e2a\u5143\u7d20\u5927\u5c0f\u7684\u4e00\u7ef4\u6570\u7ec4\u8868\u793a\u533a\u95f4\uff1a<\/p>\n<pre><code class=\"language-js line-numbers\">var nextafter = require('nextafter')\n\nvar a = [nextafter(0, Infinity), nextafter(1, -Infinity)]     \/\/ \u5f00\u533a\u95f4\nvar b = [nextafter(0, Infinity), 1]                           \/\/ \u5de6\u95ed\u53f3\u5f00\u533a\u95f4\nvar c = [0, nextafter(1, -Infinity)]                          \/\/ \u5de6\u5f00\u53f3\u95ed\u533a\u95f4\nvar d = [0, 1]                                                \/\/ \u95ed\u533a\u95f4\n<\/code><\/pre>\n<p>\u533a\u95f4\u4e0e\u96c6\u5408\u8fd0\u7b97\u7ed3\u5408\u7b26\u4f7f\u7528\uff1a<\/p>\n<ul>\n<li><em>\u4ea4\u96c6\uff08intersection\uff09<\/em> e.g. <img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5B3%2C%205%29%20%5Ccap%20%5B4%2C%206%5D%20%3D%20%5B4%2C%205%29\" alt=\"interval-intersection\" \/><\/li>\n<\/ul>\n<p><!-- [3, 5) \\cap [4, 6] = [4, 5) --><\/p>\n<ul>\n<li><em>\u5e76\u96c6\uff08union\uff09<\/em> e.g. <img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5B3%2C%205%29%20%5Ccup%20%5B4%2C%206%5D%20%3D%20%5B3%2C%206%5D\" alt=\"interval-union\" \/><\/li>\n<\/ul>\n<p><!-- [3, 5) \\cup [4, 6] = [3, 6] --><\/p>\n<ul>\n<li><em>\u5dee\u96c6\uff08difference\uff09<\/em> e.g. <img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5B3%2C%205%29%20-%20%5B4%2C%206%5D%20%3D%20%5B3%2C%204%29\" alt=\"interval-difference-1\" \/> \u8fd8\u6709 <img src=\"http:\/\/latex.codecogs.com\/svg.latex?%5B4%2C%206%5D%20-%20%5B3%2C%205%29%20%3D%20%5B5%2C%206%5D\" alt=\"interval-difference-2\" \/><\/li>\n<\/ul>\n<p><!-- [3, 5) - [4, 6] = [3, 4) --><br \/>\n<!-- [4, 6] - [3, 5)  = [5, 6] --><\/p>\n<p>\u4ee3\u7801:<\/p>\n<pre><code class=\"language-js line-numbers\">var Interval = require('interval-arithmetic')\nvar nexafter = require('nextafter')\n\nvar a = Interval(3, nexafter(5, -Infinity))\nvar b = Interval(4, 6)\n\nInterval.intersection(a, b)\n\/\/ {lo: 4, hi: 4.999999999999999}\n\nInterval.union(a, b)\n\/\/ {lo: 3, hi: 6}\n\nInterval.difference(a, b)\n\/\/ {lo: 3, hi: 3.9999999999999996}\n\nInterval.difference(b, a)\n\/\/ {lo: 5, hi: 6}\n<\/code><\/pre>\n<p>\u89c1\uff1a<\/p>\n<ul>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/scijs\/nextafter\">next-after<\/a><\/li>\n<li><a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/github.com\/maurizzzio\/interval-arithmetic\">interval-arithmetic<\/a><\/li>\n<\/ul>\n<p>code enjoy! \ud83d\udc3e\ud83d\udc3e\ud83d\udc3e\ud83d\udc3e\ud83d\udc3e\ud83d\udc3e\ud83d\udc3e\ud83d\udc3e\ud83d\udc0c\ud83d\udc1d<\/p>\n<p>\u4f5c\u8005\uff1aindeex<\/p>\n<p>\u94fe\u63a5\uff1a<a class=\"wp-editor-md-post-content-link\" href=\"https:\/\/indeex.club\/\">https:\/\/indeex.club<\/a><\/p>\n<p>\u8457\u4f5c\u6743\u5f52\u4f5c\u8005\u6240\u6709\u3002\u5546\u4e1a\u8f6c\u8f7d\u8bf7\u8054\u7cfb\u4f5c\u8005\u83b7\u5f97\u6388\u6743\uff0c\u975e\u5546\u4e1a\u8f6c\u8f7d\u8bf7\u6ce8\u660e\u51fa\u5904\u3002<\/p>\n<hr \/>\n","protected":false},"excerpt":{"rendered":"<p>\u6574\u7406\u4e00\u4e0b\uff0c\u4ee5\u4fbf\u4ee5\u540e\u67e5\u9605\u3002 \u524d\u8a00 \u6570\u5b66\u7b26\u53f7\u53ef\u4ee5\u8868\u793a\u4e0d\u540c\u7684\u610f\u601d\uff0c\u8fd9\u53d6\u51b3\u4e8e\u4f5c\u8005\uff0c\u4e0a\u4e0b\u6587\u548c\u6240\u5b66\u4e60\u7684\u9886\u57df\uff08\u7ebf\u6027<a href=\"https:\/\/blog.indeex.club\/index.php\/2021\/01\/12\/%e6%95%b0%e5%ad%a6%e6%80%9d%e6%83%b3%e7%9a%84%e4%bb%a3%e7%a0%81%e5%ae%9e%e7%8e%b0\/\" class=\"read-more\">Read More<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/posts\/221"}],"collection":[{"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/comments?post=221"}],"version-history":[{"count":1,"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/posts\/221\/revisions"}],"predecessor-version":[{"id":222,"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/posts\/221\/revisions\/222"}],"wp:attachment":[{"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/media?parent=221"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/categories?post=221"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.indeex.club\/index.php\/wp-json\/wp\/v2\/tags?post=221"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}