row/column indexing in MEX file

Hi,

I am trying to figure out if it is possible to use row/column indexing in C code mex file. For example, I want to pass a 2D array (let's say A) from Matlab command window to a mex file and manipulate it as A[i][j] += 3 inside the mex . I haven't done C programming before and am unable to find an example code in Matlab documentation that does this. Currently I am indexing it as A[i+j*n_rows] which is quite inefficient. If this is possible how do I set it up in the mex?

Thanks, Kapil

Answer 1

[James Tursa]

I don't think you are going to be able to write code that is significantly faster than A[i+j*n_rows]. You could allocate an array of column pointers and then use that to get [j][i] syntax to work, but I doubt it will be much faster.