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## Mark a matrix "upper" in a oct-file

**From**: |
Marco Caliari |

**Subject**: |
Mark a matrix "upper" in a oct-file |

**Date**: |
Fri, 5 Sep 2014 13:56:44 +0200 (CEST) |

**User-agent**: |
Alpine 2.10 (DEB 1266 2009-07-14) |

Dear all,

`I have to take the upper triangular part of a matrix in a oct-file. Later,
``I have to perform RowVector-Matrix products with it. This is my code
`
// given Matrix F(m,m)
// take the upper triangular part
for (octave_idx_type j = 0; j < m; j++)
{
for (octave_idx_type i = j+1; i < m; i++)
F(i,j) = 0.0;
}
RowVector d = F.row(0);
// make RowVector-matrix products
for (octave_idx_type i = 0; i < s-1; i++)
d = d * F;

`My question is: if I mark the matrix "upper" (but do not know how to do
``it), is the RowVector-Matrix product faster (for instance BLAS dtrmv is
``used instead of general dgemv)?
`
Thanks,
Marco

**Mark a matrix "upper" in a oct-file**,
*Marco Caliari* **<=**