Variable lamb1 appears to change size on every loop iteration

maximag=max(imag(ee));

lamb1(i1,j1)=maximag;

hello sir i m getting warning as lamb1 changes the size in every loop,because of this warning my program became very slow,can you please help me out.

[Smitesh Patil]

Are you appending maximag to lamb1 inside a loop? Its not very clear from the example here.

[nidhi humnekar]

ee = eig(AA,BB);
maximag=max(imag(ee));
  lamb1(j1,i1)=maximag;

switch ivary
     case 1
         str = 'b-';   
     case 2
         str = 'r-.';
     case 3
         str = 'k:';

[RA,DA]=meshgrid(Rac,Dac);
contour(RA,DA,lamb1',[0,0],str)
hold on
set(gca,'ytick','log')
set(gca,'xtick',0:5000:35000)
xlabel('Ra')
 ylabel('log_10 Da')
% grid on

Answer 1

[KSSV]

You have to initialize that variable before using it in a llop to save/ fill the values.

lamb1 = zeros(m,n) ;  % specify your dimensions 

[KSSV]

You need not index lamb1. Simply the below should work.

ee = eig(AA,BB);
maximag=max(imag(ee));
  lamb1 = maximag;  

switch ivary
     case 1
         str = 'b-';   
     case 2
         str = 'r-.';
     case 3
         str = 'k:';

[RA,DA]=meshgrid(Rac,Dac);
contour(RA,DA,lamb1',[0,0],str)
hold on
set(gca,'ytick','log')
set(gca,'xtick',0:5000:35000)
xlabel('Ra')
 ylabel('log_10 Da')
% grid on

[nidhi humnekar]

thank you so much sir,but when i m not definig index for lamb1 it is showing

Error using contour (line 48)

Z must be at least a 2x2 matrix.

contour(RA,ALPHA,lamb1',[0,0],str)

[KSSV]

Show us your complete code...If j1, i1 are your idnices then you have to preallocate/ initialize lamb1.

Answer 2

[Smitesh Patil]

This article on Preallocation of arrays should be helpful