常微分数值解法_数值分析 MATLAB_源码/资料下载-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/6291eec4e74b9677e8d7b765/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/6291eec4e74b9677e8d7b765/bg1.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">四阶<span class="_ _0"> </span><span class="ff2">Adams<span class="_ _0"> </span></span>方法的<span class="_ _0"> </span><span class="ff2">MA<span class="_ _1"></span>TLAB<span class="_ _0"> </span><span class="ff1">程序代码</span></span></div><div class="t m0 x2 h4 y3 ff2 fs0 fc0 sc0 ls0 ws0">format long</div><div class="t m0 x2 h4 y4 ff2 fs0 fc0 sc0 ls0 ws0">N=20;</div><div class="t m0 x2 h4 y5 ff2 fs0 fc0 sc0 ls0 ws0">M=[5 10 20 40 80];</div><div class="t m0 x2 h4 y6 ff2 fs0 fc0 sc0 ls0 ws0">for m=M</div><div class="t m0 x2 h4 y7 ff2 fs0 fc0 sc0 ls0 ws0">h=1/m;</div><div class="t m0 x2 h4 y8 ff2 fs0 fc0 sc0 ls0 ws0">t=0:h:N;</div><div class="t m0 x2 h4 y9 ff2 fs0 fc0 sc0 ls0 ws0">x=t;</div><div class="t m0 x2 h4 ya ff2 fs0 fc0 sc0 ls0 ws0">x(1)=1/2;</div><div class="t m0 x2 h4 yb ff2 fs0 fc0 sc0 ls0 ws0">k=4;</div><div class="t m0 x2 h4 yc ff2 fs0 fc0 sc0 ls0 ws0">for i=2:k</div><div class="t m0 x2 h4 yd ff2 fs0 fc0 sc0 ls0 ws0"> x(i)=exp(t(i))/(1+exp(t(i)));</div><div class="t m0 x2 h4 ye ff2 fs0 fc0 sc0 ls0 ws0">end</div><div class="t m0 x2 h4 yf ff2 fs0 fc0 sc0 ls0 ws0">for i=k:m*N</div><div class="t m0 x2 h4 y10 ff2 fs0 fc0 sc0 ls0 ws0"> x(i+1) =x(i)+h*(55/24) *x(i)*(1-x(i))-h*(59/24) *x(i-1) *(1-x(i-1)) +h*(37/24) </div><div class="t m0 x2 h4 y11 ff2 fs0 fc0 sc0 ls0 ws0">*x(i-2) *(1-x(i-2))-h*(9/24) * x(i-3) *(1-x(i-3));</div><div class="t m0 x2 h4 y12 ff2 fs0 fc0 sc0 ls0 ws0"> if mod (i+1,2* m) ==1, </div><div class="t m0 x2 h4 y13 ff2 fs0 fc0 sc0 ls0 ws0"> x (i+1) =x(i+1) +(1-exp(2))/(2*(1+exp (2)));</div><div class="t m0 x2 h4 y14 ff2 fs0 fc0 sc0 ls0 ws0"> end</div><div class="t m0 x2 h4 y15 ff2 fs0 fc0 sc0 ls0 ws0">end</div><div class="t m0 x2 h4 y16 ff2 fs0 fc0 sc0 ls0 ws0">%error=(x(m*N+1)-(1-exp(2))/(2*(1+exp(2)))-exp(2)/(1+exp(2)));</div><div class="t m0 x2 h4 y17 ff2 fs0 fc0 sc0 ls0 ws0">error=(x(m*N+1)-(1-exp(2))/(2*(1+exp(2)))-exp(2)/(1+exp(2)))/(exp(2)/(1+exp(2))),</div><div class="t m0 x2 h4 y18 ff2 fs0 fc0 sc0 ls0 ws0">end</div><div class="t m0 x2 h4 y19 ff2 fs0 fc0 sc0 ls0 ws0">plot(t,x)</div><div class="t m0 x2 h4 y1a ff2 fs0 fc0 sc0 ls0 ws0">hold on </div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div> </body> </html>