kagelangr.txt

一个计算拉个朗日插值很好的程序

 h0=figure('toolbar','none',...
                  'position',[200 50 350 450],...
                  'name','实例85');
              h1=axes('parent',h0,...
                  'position',[0.10 0.45 0.8 0.5],...
                  'visible','off');
              x=0:0.2:2*pi;
              y=sin(x);
              plot(x,y)
              b1=uicontrol('parent',h0,...
                  'units','points',...
                  'tag','b1',...
                  'style','pushbutton',...
                  'string','拉格朗日插值',...
                  'backgroundcolor',[0.75 0.75 0.75],...
                  'position',[20 60 70 20],...
                  'callback',[...
                      'cla,',...
                      'strn=get(e1,''string'');,',...
                      'n=str2num(strn);,',...
                      'i=1;,',...
                      'x=0:0.2:2*pi;,',...
                      'for t=0:0.2:2*pi,',...
                      'y(i)=sin(t);,',...
                      'L(i)=lag(t,n);,',...
                      'i=i+1;,',...
                      'end,',...
                      'plot(x,y,''b*'',x,L,''r-''),',...
                      'legend(''sin(x)'',''插值函数'');,',...
                      'axis([0 7 -1.5 1.5])']);
              b2=uicontrol('parent',h0,...
                  'units','points',...
                  'tag','b2',...
                  'style','pushbutton',...
                  'string','误差比较',...
                  'backgroundcolor',[0.75 0.75 0.75],...
                  'position',[170 60 70 20],...
                  'callback',[...
                      'strn=get(e1,''string'');,',...
                      'n=str2num(strn);,',...
                      'strm=get(e2,''string'');,',...
                      'm=str2num(strm);,',...
                      'dd=abs(sin(m)-lag(m,n));,',...
                      'msgbox([''误差为：'',num2str(dd)],''计算结果'')']);
              e1=uicontrol('parent',h0,...
                  'units','points',...
                  'tag','e1',...
                  'style','edit',...
                  'fontsize',12,...
                  'string','5',...
                  'horizontalalignment','right',...
                  'backgroundcolor',[1 1 1],...
                  'position',[50 100 40 20]);
              e2=uicontrol('parent',h0,...
                  'units','points',...
                  'tag','e2',...
                  'style','edit',...
                  'fontsize',12,...
                  'string','1.20',...
                  'horizontalalignment','right',...
                  'backgroundcolor',[1 1 1],...
                  'position',[200 100 40 20]);
              t1=uicontrol('parent',h0,...
                  'units','points',...
                  'tag','t1',...
                  'style','text',...
                  'string','阶数：',...
                  'fontsize',12,...
                  'backgroundcolor',[0.75 0.75 0.75],...
                  'position',[20 100 30 20]);
              t2=uicontrol('parent',h0,...
                  'units','points',...
                  'tag','t2',...
                  'style','text',...
                  'string','误差点：',...
                  'fontsize',12,...
                  'backgroundcolor',[0.75 0.75 0.75],...
                  'position',[160 100 40 20]);
              b3=uicontrol('parent',h0,...
                  'units','points',...
                  'tag','b3',...
                  'style','pushbutton',...
                  'string','关闭',...
                  'backgroundcolor',[0.75 0.75 0.75],...
                  'position',[100 20 60 20],...
                  'callback','close');