误差曲线（Matlab）

 loglog(dof(:),errorestimate(:),'--^',dof1(:),errorestimate1(:),'r*--','MarkerSize',);hold on;
 loglog(dof(:),eigvalue(:)-[13.0863416259350;],'kO-','MarkerSize',);%[13.0863323929054;][13.0863322295266;]
 loglog(dof1(:-),eigvalue1(:-)-[13.0863416259350;],'+-','MarkerSize',,'Color',[.  ]);
 xlabel('degree of freedom','fontsize',);ylabel('error of the first eigenvalue','fontsize',);
 a=regress(log10(errorestimate(:)),[ones(,) log10(dof(:))]);
 x=linspace(dof(),max(dof1));y=.^(a()+0.5)*x.^a();hold on; loglog(x,y,'m--')
 legend('error indicator for Algorithm 4.1','error indicator for Algorithm 4.2','true error for Algorithm 4.1','true error for Algorithm 4.2',...
     strcat('a line with slope=',num2str(a())),);axis tight;

Error curve