matlab简介_matlab_matlab例程_数值算法/人工智能下载-pudn.com

<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8"> <meta name="generator" content="pdf2htmlEX"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <link rel="stylesheet" href="https://static.pudn.com/base/css/base.min.css"> <link rel="stylesheet" href="https://static.pudn.com/base/css/fancy.min.css"> <link rel="stylesheet" href="https://static.pudn.com/prod/directory_preview_static/6277ebd1517cd20ea494fe05/raw.css"> <script src="https://static.pudn.com/base/js/compatibility.min.js"></script> <script src="https://static.pudn.com/base/js/pdf2htmlEX.min.js"></script> <script> try{ pdf2htmlEX.defaultViewer = new pdf2htmlEX.Viewer({}); }catch(e){} </script> <title></title> </head> <body> <div id="sidebar" style="display: none"> <div id="outline"> </div> </div> <div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/6277ebd1517cd20ea494fe05/bg1.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">1.MA<span class="_ _0"></span>TLAB <span class="ff2 sc1">开发环境</span></div><div class="t m0 x2 h3 y3 ff1 fs0 fc0 sc0 ls0 ws0">1.1 MA<span class="_ _0"></span>TLAB <span class="ff2 sc1">的视窗环境</span></div><div class="t m0 x3 h3 y4 ff2 fs0 fc0 sc0 ls0 ws0">进入<span class="_ _1"> </span><span class="ff3">MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">之后，会看到一个视窗<span class="_ _1"> </span></span>MA<span class="_ _2"></span>TLAB Command W<span class="_ _3"></span>indow<span class="_ _1"> </span><span class="ff2">称为指令视窗，它是你</span></span></div><div class="t m0 x2 h3 y5 ff2 fs0 fc0 sc0 ls0 ws0">键入指令的地方同时<span class="ff3"> MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">也将计算结果显示在此。</span></span></div><div class="t m0 x2 h3 y6 ff1 fs0 fc0 sc0 ls0 ws0">1.2 <span class="ff2 sc1">简易计算</span></div><div class="t m0 x3 h3 y7 ff2 fs0 fc0 sc0 ls0 ws0">我们<span class="_ _4"></span>先从<span class="_ _5"> </span><span class="ff3">MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">的数<span class="_ _4"></span>学运<span class="_ _4"></span>算开<span class="_ _4"></span>始说<span class="_ _4"></span>明。<span class="_ _4"></span>就像<span class="_ _4"></span>计算<span class="_ _4"></span>器一<span class="_ _4"></span>样，<span class="_ _4"></span>数学<span class="_ _4"></span>式的<span class="_ _4"></span>计算<span class="_ _4"></span>是直<span class="_ _4"></span>接了<span class="_ _4"></span>当。</span></span></div><div class="t m0 x2 h3 y8 ff2 fs0 fc0 sc0 ls0 ws0">如果我们要<span class="_ _4"></span>算<span class="ff3"> 1+2<span class="_ _4"></span>+3<span class="_ _1"> </span></span>及<span class="_ _1"> </span><span class="ff3">1×10+2×20+3×30<span class="_ _1"> </span></span>这二个式子，<span class="_ _4"></span>它们就是接在<span class="_ _4"></span>提示符号<span class="_ _4"></span><span class="ff3">>><span class="_ _4"></span></span>之后要键入<span class="_ _4"></span>的</div><div class="t m0 x2 h3 y9 ff2 fs0 fc0 sc0 ls0 ws0">算式<span class="_ _4"></span>，<span class="_ _4"></span><span class="ff3">MA<span class="_ _2"></span>TLAB<span class="_"> </span><span class="ff2">将计算<span class="_ _4"></span></span> <span class="_ _4"></span><span class="ff2">的<span class="_ _4"></span>结果<span class="_ _4"></span>以<span class="_ _5"> </span></span>ans<span class="_ _1"> </span><span class="ff2">显示<span class="_ _4"></span>。<span class="_ _4"></span>如果<span class="_ _4"></span>算<span class="_ _4"></span>式是<span class="_ _5"> </span></span>x=1<span class="_ _4"></span>+2+3<span class="ff2">，<span class="_ _4"></span></span>MA<span class="_ _2"></span>TLAB<span class="_"> </span><span class="ff2">将计<span class="_ _4"></span>算的<span class="_ _4"></span>结<span class="_ _4"></span>果以</span></span></div><div class="t m0 x2 h3 ya ff3 fs0 fc0 sc0 ls0 ws0">x<span class="_ _1"> </span><span class="ff2">显示。</span> </div><div class="t m0 x2 h4 yb ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> 1+2+3 </span></div><div class="t m0 x2 h4 yc ff3 fs0 fc0 sc0 ls0 ws0"> ans = </div><div class="t m0 x2 h4 yd ff3 fs0 fc0 sc0 ls0 ws0"> 6 </div><div class="t m0 x2 h4 ye ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> 1*10 + 2*20 + 3*30 </span></div><div class="t m0 x2 h4 yf ff3 fs0 fc0 sc0 ls0 ws0"> ans = </div><div class="t m0 x2 h4 y10 ff3 fs0 fc0 sc0 ls0 ws0"> 140 </div><div class="t m0 x2 h4 y11 ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> x=1+2+3 </span></div><div class="t m0 x2 h4 y12 ff3 fs0 fc0 sc0 ls0 ws0"> x = </div><div class="t m0 x3 h4 y13 ff3 fs0 fc0 sc0 ls0 ws0">6 </div><div class="t m0 x3 h3 y14 ff2 fs0 fc0 sc0 ls0 ws0">如果<span class="_ _4"></span>在<span class="_ _4"></span>上述<span class="_ _4"></span>的<span class="_ _4"></span>例子<span class="_ _4"></span>结<span class="_ _4"></span>尾加<span class="_ _4"></span>上<span class="_ _7"></span> <span class="_ _8"> </span> <span class="_ _9"></span><span class="ff3">;<span class="_ _a"></span><span class="ff2"> <span class="_ _a"></span> ，则<span class="_ _4"></span>计算<span class="_ _4"></span>结<span class="_ _4"></span>果不<span class="_ _4"></span>会<span class="_ _4"></span>显示<span class="_ _4"></span>在<span class="_ _4"></span>指令<span class="_ _4"></span>视<span class="_ _4"></span>窗上<span class="_ _4"></span>，<span class="_ _4"></span>要得<span class="_ _4"></span>知<span class="_ _4"></span>计算<span class="_ _4"></span>值<span class="_ _4"></span>只须<span class="_ _4"></span>键<span class="_ _b"></span> <span class="_ _c"> </span> </span></span></div><div class="t m0 x2 h3 y15 ff2 fs0 fc0 sc0 ls0 ws0">入该变数值即可<span class="ff3"> </span></div><div class="t m0 x2 h4 y16 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> x=1+2+3; </span></div><div class="t m0 x2 h4 y17 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> x </span></div><div class="t m0 x3 h4 y18 ff3 fs0 fc0 sc0 ls0 ws0">x = </div><div class="t m0 x3 h4 y19 ff3 fs0 fc0 sc0 ls0 ws0">6</div><div class="t m0 x3 h3 y1a ff2 fs0 fc0 sc0 ls0 ws0">以下的例子显示<span class="_ _1"> </span><span class="ff3">MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">对使用变量的弹性</span> </span></div><div class="t m0 x2 h4 y1b ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> apple=5 </span></div><div class="t m0 x3 h4 y1c ff3 fs0 fc0 sc0 ls0 ws0">apples = </div><div class="t m0 x3 h4 y1d ff3 fs0 fc0 sc0 ls0 ws0">5 </div><div class="t m0 x2 h4 y1e ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> orange=10 </span></div><div class="t m0 x3 h4 y1f ff3 fs0 fc0 sc0 ls0 ws0">orange = </div><div class="t m0 x3 h4 y20 ff3 fs0 fc0 sc0 ls0 ws0">10 </div><div class="t m0 x2 h4 y21 ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> total_cost=apple*3+orange*3</span></div><div class="t m0 x3 h4 y22 ff3 fs0 fc0 sc0 ls0 ws0">total_cost = </div><div class="t m0 x3 h4 y23 ff3 fs0 fc0 sc0 ls0 ws0">45 </div><div class="t m0 x2 h4 y24 ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> average_cost=total_cost/(apple+orange) ??</span></div><div class="t m0 x3 h4 y25 ff3 fs0 fc0 sc0 ls0 ws0">average_cost = </div><div class="t m0 x3 h4 y26 ff3 fs0 fc0 sc0 ls0 ws0">7.6</div><div class="t m0 x2 h3 y27 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">提供基本的算术运算有：</span> </span></div><div class="t m0 x3 h3 y28 ff2 fs0 fc0 sc0 ls0 ws0">加<span class="ff3"> (+)</span>、减<span class="ff3"> (-)</span>、乘<span class="ff3"> (*)</span>、除<span class="ff3"> (/)</span>、幂次方<span class="ff3"> (^)</span>，范例为：<span class="ff3">5<span class="_ _4"></span>+3, 5-3, 5*3, 5/3, 5^3</span></div><div class="t m0 x2 h3 y29 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff2 fs0">其<span class="_ _4"></span>它关<span class="_ _4"></span>于<span class="_ _4"></span>计<span class="_ _4"></span>算<span class="_ _4"></span>常<span class="_ _4"></span>用的<span class="_ _4"></span>功<span class="_ _4"></span>能<span class="_ _4"></span>我<span class="_ _4"></span>们<span class="_ _4"></span>通<span class="_ _4"></span>过<span class="_ _4"></span>一个<span class="_ _4"></span>算<span class="_ _4"></span>式<span class="_ _4"></span>来<span class="_ _4"></span>说<span class="_ _4"></span>明。<span class="_ _4"></span>要<span class="_ _4"></span>计<span class="_ _4"></span>算<span class="_ _4"></span>面<span class="_ _4"></span>积<span class="_ _5"> </span><span class="ff3">Area =π<span class="_ _4"></span> r</span></span></div><div class="t m0 x4 h5 y2a ff3 fs3 fc0 sc0 ls0 ws0">2</div><div class="t m0 x5 h3 y29 ff3 fs0 fc0 sc0 ls0 ws0"> <span class="_ _4"></span> ,<span class="_ _4"></span><span class="ff2">半<span class="_ _4"></span>径<span class="_ _5"> </span><span class="ff5">r </span></span>= <span class="_ _4"></span>2<span class="_ _4"></span><span class="ff2">，</span></div><div class="t m0 x2 h3 y2b ff2 fs0 fc0 sc0 ls0 ws0">则可键入<span class="ff3"> </span></div><div class="t m0 x2 h4 y2c ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> r=2; </span></div><div class="t m0 x2 h4 y2d ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> area=pi*r^2; </span></div><div class="t m0 x2 h4 y2e ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> area = </span></div><div class="t m0 x3 h4 y2f ff3 fs0 fc0 sc0 ls0 ws0">12.5664</div><div class="t m0 x2 h3 y30 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff2 fs0">我们也可以将上述指令打在同一行，以<span class="ff3">, </span>或是<span class="ff3">; </span>分开，例如<span class="ff3"> </span></span></div><div class="t m0 x2 h4 y31 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> r=2, area=pi*r^2 </span></div><div class="t m0 x2 h4 y32 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> r=2; area=pi*r^2;</span></div></div></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div> </body> </html>

<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/6277ebd1517cd20ea494fe05/bg2.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x2 h3 y2 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff2 fs0">请注意上述二式的差异</span></div><div class="t m0 x3 h3 y3 ff2 fs0 fc0 sc0 ls0 ws0">前者有计算值显示，而后者则无。</div><div class="t m0 x2 h3 y4 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff2 fs0">如果一个指令过长可以在结尾加上<span class="ff3">...</span>（代表此行指令与下一行连续），例如<span class="ff3"> </span></span></div><div class="t m0 x2 h4 y33 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> r=2; </span></div><div class="t m0 x2 h4 y34 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> area = pi ... </span></div><div class="t m0 x2 h4 y35 ff3 fs0 fc0 sc0 ls0 ws0"> <span class="_ _6"> </span>*r^2</div><div class="t m0 x2 h3 y36 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff2 fs0">另外注解是由符号<span class="ff3">%</span>起头，也就是说在<span class="ff3">%</span>之后的任何文字都被视为程序的注解。例如<span class="ff3"> </span></span></div><div class="t m0 x2 h3 y37 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> r=2; % <span class="ff2">键入半径</span> </span></div><div class="t m0 x2 h3 y38 ff4 fs2 fc0 sc0 ls0 ws0"><span class="_ _d"> </span><span class="ff3 fs0">>> area=pi*r^2; % <span class="ff2">计算面积</span> </span></div><div class="t m0 x2 h3 y39 ff1 fs0 fc0 sc0 ls0 ws0">1.3 <span class="ff2 sc1">变量</span></div><div class="t m0 x3 h3 y3a ff3 fs0 fc0 sc0 ls0 ws0">MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">对使用变量名称的规定：</span> </div><div class="t m0 x2 h3 y3b ff4 fs4 fc0 sc0 ls0 ws0"><span class="_ _e"> </span><span class="ff2 fs0">变量名称的英文大小写是有区别的（<span class="ff3">apple, <span class="_ _0"></span>Apple, <span class="_ _3"></span>AppLe<span class="ff2">，三个变量不同）。</span> </span></span></div><div class="t m0 x2 h3 y3c ff4 fs4 fc0 sc0 ls0 ws0"><span class="_ _e"> </span><span class="ff2 fs0">变量的长度上限为<span class="ff3"> 19 </span>个字符。<span class="ff3"> </span></span></div><div class="t m0 x2 h3 y3d ff4 fs4 fc0 sc0 ls0 ws0"><span class="_ _e"> </span><span class="ff2 fs0">变量名的第一个字必须是一英文字，随后可以掺杂英文字、数字或下划线。</span></div><div class="t m0 x2 h3 y3e ff3 fs0 fc0 sc0 ls0 ws0"> <span class="ff2">特别要注意文件的命名，如：</span>1<span class="ff2">、实验一等</span></div><div class="t m0 x2 h3 y3f ff2 fs0 fc0 sc0 ls0 ws0">以下列出<span class="_ _1"> </span><span class="ff3">MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">所定义的特别变量及其意义</span></span></div><div class="t m0 x6 h3 y40 ff2 fs0 fc0 sc0 ls0 ws0">变量名<span class="_ _f"> </span>意义</div><div class="t m0 x6 h4 y41 ff3 fs0 fc0 sc0 ls0 ws0">Help</div><div class="t m0 x7 h3 y42 ff2 fs0 fc0 sc0 ls0 ws0">线上说明<span class="ff3">, </span>如<span class="ff3"> help quit </span></div><div class="t m0 x6 h4 y43 ff3 fs0 fc0 sc0 ls0 ws0">Who</div><div class="t m0 x7 h3 y44 ff2 fs0 fc0 sc0 ls0 ws0">列出所有定义过的变量名称<span class="ff3"> </span></div><div class="t m0 x6 h4 y45 ff3 fs0 fc0 sc0 ls0 ws0">ans</div><div class="t m0 x7 h3 y46 ff2 fs0 fc0 sc0 ls0 ws0">预设的计算结果的变量名<span class="ff3"> </span></div><div class="t m0 x6 h4 y47 ff3 fs0 fc0 sc0 ls0 ws0">eps</div><div class="t m0 x7 h3 y48 ff3 fs0 fc0 sc0 ls0 ws0">MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">定义的正的极小值</span>=2.2204e-16 </div><div class="t m0 x6 h4 y49 ff3 fs0 fc0 sc0 ls0 ws0">pi</div><div class="t m0 x7 h3 y4a ff2 fs0 fc0 sc0 ls0 ws0">内建的<span class="_ _1"> </span><span class="ff3">π<span class="_ _1"> </span></span>值<span class="ff3"> </span></div><div class="t m0 x6 h4 y4b ff3 fs0 fc0 sc0 ls0 ws0">inf</div><div class="t m0 x7 h3 y4c ff6 fs0 fc0 sc0 ls0 ws0">∞<span class="ff2">值，无限大<span class="ff3"> (1/0 ) </span></span></div><div class="t m0 x6 h4 y4d ff3 fs0 fc0 sc0 ls0 ws0">NaN</div><div class="t m0 x7 h3 y4e ff2 fs0 fc0 sc0 ls0 ws0">无法定义一个数目<span class="ff3"> ( 0/0) </span></div><div class="t m0 x3 h3 y4f ff1 fs0 fc0 sc0 ls0 ws0">MA<span class="_ _0"></span>TLAB<span class="_ _1"> </span><span class="ff2 sc1">中的变量都是矩阵：</span> </div><div class="t m0 x2 h4 y50 ff3 fs0 fc0 sc0 ls0 ws0"> A<span class="_ _0"></span> <span class="_ _4"></span>column vector is an m-by-1 matrix, a row vector is a 1-by-n matrix and a scalar is a 1-by-1 matrix</div><div class="t m0 x2 h4 y51 ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> x=[1; 2; 3]</span></div><div class="t m0 x2 h4 y52 ff3 fs0 fc0 sc0 ls0 ws0"> x =</div><div class="t m0 x2 h4 y53 ff3 fs0 fc0 sc0 ls0 ws0"> 1</div><div class="t m0 x2 h4 y54 ff3 fs0 fc0 sc0 ls0 ws0"> 2</div><div class="t m0 x2 h4 y55 ff3 fs0 fc0 sc0 ls0 ws0"> 3</div><div class="t m0 x2 h4 y56 ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> y=[1,2,3]</span></div><div class="t m0 x2 h4 y57 ff3 fs0 fc0 sc0 ls0 ws0"> y =</div><div class="t m0 x2 h4 y58 ff3 fs0 fc0 sc0 ls0 ws0"> 1 2 3</div><div class="t m0 x2 h4 y59 ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>>c=y*x</span></div><div class="t m0 x2 h4 y5a ff3 fs0 fc0 sc0 ls0 ws0"> c =</div><div class="t m0 x2 h4 y5b ff3 fs0 fc0 sc0 ls0 ws0"> 14</div><div class="t m0 x3 h3 y5c ff3 fs0 fc0 sc0 ls0 ws0">MA<span class="_ _2"></span>TLAB<span class="_ _1"> </span><span class="ff2">中的变量：</span> </div><div class="t m0 x2 h4 y5d ff3 fs0 fc0 sc0 ls0 ws0"> A<span class="_ _0"></span> <span class="_ _4"></span>column vector is an m-by-1 matrix, a row vector is a 1-by-n matrix and a scalar is a 1-by-1 matrix</div><div class="t m0 x2 h4 y5e ff4 fs1 fc0 sc0 ls0 ws0"><span class="_ _6"> </span><span class="ff3 fs0">>> x=[1; 2; 3]</span></div><div class="t m0 x2 h4 y5f ff3 fs0 fc0 sc0 ls0 ws0"> x =</div></div></div><div class="pi" data-data='{"ctm":[1.568627,0.000000,0.000000,1.568627,0.000000,0.000000]}'></div></div>