matrix vector

[John W. Eaton]

On 23-Jun-2003, Matthew Wollenweber <address@hidden> wrote:

| i'm not too familiar with fortran. 
| 
| I'm curious if I have:
| 
| Matrix M(x,y);
| double *P;
| 
| P = M.fortran_vec();
| 
| Is P in raster order? If anyone Is particularly use to image processing,
| I'm attempting to use octave with Thevenaz and Unser's spline code and i'm
| not sure if I'm passing in the Matrix correctly.

I'm not sure what "raster order" means.

The data in an Octave Matrix object is stored in column-major order.
I.e., for the matrix

  [1,2;
   3,4]

the vector of values returned by fortran_vec() will be

  [1, 3, 2, 4]

You could have verified this by either looking at the code for the
Matrix/Array classes in Octave, or by doing a simple experiment.

jwe



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