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

% 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).

Answer 1

[KSSV]

Try this:

% Sample Code
tol = 10^-3 ;    % can be changed 
idx = find(abs(sample.data1-values)<tol) ;
max_index = idx(1) ; 

[Praveen Kumar]

Thanks for quick response. The mentioned method gives the right values, but the error still persists.

I think it still cant figure out the size of 'idx' and 'max_index' (Size: Inf x Inf).

FYI, the error is highlighted in in the line: X = sample.data1(max_index - 100: max_index + 100); where max_index - 100 is highlighted in red.

[KSSV]

Check the value of idx(1) or max_index. You need to show us the data i.e. sample and values to solve the error.

1. Is values a single number or array?
2. Does your sample.data1 has values less than values?

[Praveen Kumar]

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]

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.