multiplication of empty 0X0 double and scalar (1X1)
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Rohit Mangalekar
on 14 Sep 2021
Commented: Rohit Mangalekar
on 17 Sep 2021
Hello,
I am trying to calculate sum of certain maximum elements of arrays. When some of these variables are not available in the program (due to if statement), then the maximum value of element of these variable array comes out to be 0X0 double (as I have by default defined the variable as a cell array of zeros).
The problem I am facing is an error "Unable to perform assignment because the indices on the left side are not compatible with the size of the right side."
I think the error is due to the multiplication part of two variables on the right side of equation i.e. - 0X0 double and one scalar. The other (left) side of equation (sum) is supposed to produce the scalar value.
How to handle this and get the scalar output on left side by ignoring these "absent" variables value (assigned 0 X0 double and a scalar)???
Can anybody help with this small issue and guide me on this, please?
A=cell(1,5);
B=cell(1,5);
C=cell(1,5);
a=1;
b=2;
c=3;
if.......
% A, B or C is not used and modified.
% Say A is not used or modified.
end...
AA=max(A);
BB=max(B);
CC=max(C);
DD=max(D);
sum= max(AA*a+BB*b+CC*c+DD*d);
% AA is now 0X0 double and a is 1 (1X1 double).
% Is this causing problem???
1 Comment
Walter Roberson
on 15 Sep 2021
You can check with isempty()
However, you cannot take max() of a cell .
Accepted Answer
the cyclist
on 14 Sep 2021
One possible solution is to use a try-catch structure. The "try" block will be the code that is generally executed, but if that section fails (due to the empty array), then the "catch" block will be executed instead.
4 Comments
Walter Roberson
on 15 Sep 2021
if isempty(sum) ;sum=0; end
do that before you attempt to assign sum into a subscripted variable.
... and don't use "sum" as a variable name. Chances are too high that you will end up also wanting to use the function sum() .And besides, it confuses readers.
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