Problem with set field by number
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Hi
I am having a problem using mxSetFieldByNumber. I want to set fields in a N-D structure array. I have no problem with setting fields in a Nx1 structure array. With a Nx1 structure array index is set as a int and corresponds to the element I want to write data.
int index;
field_num = mxGetFieldNumber(pa, "field_name");
mxSetFieldByNumber(pa, index, field_num, new_value_pa);
But with a N-D structure array I cant seem to find a way to write data to the second column in the array. I if I Have a 6x2 structure array I can set data to the first column in the array by setting the index to 1...6. I tried to set index 7 but then the structure array is changed to a array with dimensions of 7x2.
What should I do to populate the second column of the array? Thank You Joachim
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Accepted Answer
Jan
on 1 Aug 2013
Edited: Jan
on 1 Aug 2013
Using index=7 is the perfect method to set the [1 x 2] elements of a [6 x N] array, e.g. a struct array also. So please post a piece of code, which reproduces your problem. You cannot change the size of a (struct)-array inside C++ only by writing to a non-existent index. While this works in Matlab, it crashes the memory manager in C++. So perhaps all you see is a severe bug.
More Answers (1)
Philip Borghesani
on 1 Aug 2013
If you are trying to grow an existing structure then you will need to reshape the structure when done. If you create the structure ahead of time with mxCreateStructArray then this will not happen. I hope you are not modifying a structure input to the mex function.
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