Matlab Warning: Concatenation of empty arrays

Hi,

I have write these lines in a matlab function

[r2, c2] = find(row == -2);

[r10, c10] = find(row == -10);

[r11, c11] = find(row == -11);

[r15, c15] = find(row == -15);

c = [c2 c10 c11 c15];

When I run the function on the matlab prompt I visualize this warning on the last line of the above code

Warning: Concatenation involves an empty array with an incorrect number of rows.

How can I resolve this warning?

Thanks in advance

Andrew

[Walter Roberson]

Please tell us what you get for

size(c2)
size(c10)
size(c11)
size(c15)

Answer 1

[Azzi Abdelmalek]

Because c2 and c10, for example, have not the same size, then you can't concatenate them horizontally. Use instead

c = [c2 ;c10; c11; c15];

Answer 2

[Walter Roberson]

Perhaps this would be suitable?

c = find(row == -2 | row == -10 | row == -11 | row = -15);

which could also be coded as

c = find(ismember(row, [-2, -10, -11, -15]));

[Andrea]

row is a row vector can be contains or a single value between {-2,-10,-11,-15} or a combination of its.

I should select the max column of the values contained in row and in fact in my code I have this:

c = [c2 c10 c11 c15]; c = max(c);

I obtain the same behaviour with this instruction, for example:

c = max(find(ismember(row, [-2, -10, -11, -15])));

Thanks

Andrew