Expected a scalar value. This expression has size [:? x 1].

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% Sample Code
max_index = find(sample.data1 == values,1,'first');
% max_index is always above 100 based on the nature of the data
X = sample.data1(max_index - 100: max_index + 100);
Y = sample.data2(max_index - 100: max_index + 100);
I was trying to generate code based on MATLAB coder, however I am stuck with the error: 'Expected a scalar value. This expression has size [:? x 1].'
I understand that max_index could be empty or (max_index - 100) could be empty, hence this error. How to properly declare those variables to avoid this error?
Max_index is scalar value and cannot be below 100 based on the nature of used data (also used If loops to avoid such condition).

Accepted Answer

KSSV
KSSV on 1 Feb 2023
Try this:
% Sample Code
tol = 10^-3 ; % can be changed
idx = find(abs(sample.data1-values)<tol) ;
max_index = idx(1) ;
  4 Comments
Praveen Kumar
Praveen Kumar on 1 Feb 2023
Edited: Praveen Kumar on 1 Feb 2023
Sorry, the code works!
Previously I had pre-intialized max_index to variable size using: coder.varsize('max_index').
Removed the same and the coder generates without any error.
Praveen Kumar
Praveen Kumar on 1 Feb 2023
Thanks again. Just to clarify your question.
  1. 'Values' is a single number. (I should have declared as 'Value' here (or mentioned), to avoid confusion )
  2. sample.data1 is a (nx1) vector, n>1000.

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