Looking at Type inferencing compiler

[John W. Eaton]

On 11-Dec-2006, David Bateman wrote:

| So the only example above that is faster than the m-file is yours!!! Do
| you or anyone else know where I'm paying the speed penalty for the
| octave in-built classes? In any case I suspect that the improvement you
| showed in the example in your thesis was largely due to the different
| matrix class that the type inferencing, though further benchmarks will
| be needed to prove that.

|     inline operator octave_value(){ 
|       Matrix m(rows,cols); for (int i = 0; i<rows; ++i) for ( int j = 0 ; 
j<cols; ++j ) m(i,j) = rep[i][j];
|       return m;
|     };

It's not clear to me whether this conversion operator is being used,
but it will be slow because the indexing operator for the Matrix class
must check the reference count each time it is called.  You can fix
that by doing

  inline operator octave_value(){ 
    Matrix m(rows,cols);
    double *mp = m.fortran_vec ();
    int k = 0;
    for (int j = 0 ; j<cols; ++j)
      for (int i = 0; i<rows; ++i)
        mp[k++] = rep[i][j];
    return m;
  }

jwe