Empty matrix: 0-by-1

Dears, I have a problem. I try to find a cretin value (Eexc) obtained from equation in an input array(E).

[ro,co]=find(E==Eexc)

i have got this error message. Empty matrix: 0-by-1

Regards,

Answer 1

[Azzi Abdelmalek]

A=[1 2 3]
find(A==5)

The result is

ans =
 Empty matrix: 1-by-0

Because 5 is not found in A

Answer 2

[Star Strider]

Could be a problem in floating-point approximation inaccuracies, the result of expressing decimal numbers in binary format.

See if:

[ro,co]=find(abs(E-Eexc) <= 1E-8)

works. This introduces a tolerance to the comparison. You may need to experiment with it to get the result you want.

[laser laser12]

Dear, thank you for your answer. I tried it also but it does not work.It shows many values of Co and Ro. I found something in Matlab help which it worked.

tmp = abs(E-Eexc);

[ro ro] = min(tmp); %index of closest value

closest = E(ro);

Regards

[Star Strider]

O.K. I’m glad you got it sorted out.

I was going to suggest you varied the tolerance, perhaps lowering it to 1E-10 or lower, until you got the result you wanted.

[Image Analyst]

Most of us know about that min() trick. It would have been good to share the larger context of what you wanted (finding the closest index) in the first place rather than having us try to fix some approach that you thought of that turned out to be not very good. However, it still needs fixing. It's not good to have ro in both outputs of min. You should do it like this:

[minValue, indexOfClosestValue] = min(abs(E-Eexc)); %index of closest value
closestEValue = E(indexOfClosestValue);

[Bachtiar Muhammad Lubis]

I face the same issue like him. I have codes that look like:

        load template;
          comp=[];
          for n=1:num_char
            sem = corr2(template{1,n},img);
            comp = [comp sem];
          end
        vd = find(comp==max(comp));

vd return Empty matrix: 1-by-0. In my case i only need a value. If i use abs() function the velue would be integer while i need rill number (i.e. either 1 or 0,5 etc.) And. Also if i use 1E-8 it would be return more than one value while i only need a value. Can you guys help me to solve my problem please.