Re: Error about mkoctfile and Octave update..Thank you!

[Søren Hauberg]

Hi,
  First of all I wouldn't use pointers if I were you. You didn't
say what you're problem was so I'm guessing a bit. Your program
has a few bugs:
1) resAddm is const yet you try to alter it's values.
2) in C++ matrices use zero based indexing -- you use 1 based indexing.
Other then that you program should work. Here is a fixed version:

#include <octave/oct.h>
DEFUN_DLD (addoctmatr, args, ,
 "The addition of two spreaded matrices.")
{
    octave_value_list retval;

    const Matrix Am = args(0).matrix_value();
    int mrows = Am.rows();
    int ncols = Am.cols();
    const Matrix Bm = args(1).matrix_value();
    Matrix resAddm (mrows, ncols);
    for(int i = 0; i < mrows; i++)
    {
        for(int j = 0; j < ncols; j++)
        {
            resAddm(i,j) = Am(i,j) + Bm(i,j);
        }
    }
    retval.append(resAddm);
    return retval;
}


Hope that helps,
Søren


钟 伟生 skrev:
> Dear All,
>
> I am a new comer to the octave andI tried to write an .cc file about the 
> addition of two integral matrices. But there are still too many warning 
> when i mkoctfile it...
> I would be so grateful for any help. Another, my octave release is 
> 2.1.73 under cygwin, is anyone know how to update to 2.9.8...I download 
> the 2.9.8 file, but how to install?
>
> Thank you very much!
>
> Best Regards,
> Weisheng
>
> #include <octave/oct.h>
> DEFUN_DLD (addoctmat, args, ,
>  "The addition of two spreaded matrices.")
> {
>     octave_value retval;
>     const Matrix Am = args(0).matrix_value();
>     double *A = Am.fortran_vec();
>     int mrows = Am.rows();
>     int ncols = Am.cols();
>     const Matrix Bm = args(1).matrix_value();
>     double *B = Bm.fortran_vec();
>     const Matrix resAddm (mrows, ncols);
>     double *resAdd = resAddm.fortran_vec();
>     
>     resAdd[0] = 0.0;
>     for (int i = 0; i < mrows; i++)
>     {
>         for (int j = 0; j < ncols; j++)
>         {
>             *(resAdd+j*mrows+i) = *(Am+j*mrows+i) + *(Bm+j*mrows+i);
>         }
>     }
>     retval = resAddm;
>     return retval;
> }
>
> And, if I donot use the pointer, is seems better...but still donot 
> work.....
>
> #include <octave/oct.h>
> DEFUN_DLD (addoctmatr, args, ,
>  "The addition of two spreaded matrices.")
> {
>     octave_value retval;
>
>     const Matrix Am = args(0).matrix_value();   
>     int mrows = Am.rows();
>     int ncols = Am.cols();   
>     const Matrix Bm = args(1).matrix_value();
>     const Matrix resAddm (mrows, ncols);
>     for(int i = 1; i <= mrows; i++)
>     {
>         for(int j = 1; j <= ncols; j++)
>         {
>             resAddm(i,j) = Am(i,j) + Bm(i,j);
>         }
>     }
>     retval = resAddm;
>     return retval;
> }
>
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