bl1_set_contig_strides.c File Reference

(r)

Functions
void	bl1_set_contig_strides (int m, int n, int *rs, int *cs)

Function Documentation

bl1_set_contig_strides()

void bl1_set_contig_strides	(	int	m,
		int	n,
		int *	rs,
		int *	cs
	)

{
    // Default to column-major order.
    *rs = 1;
    *cs = m;
 
    // Handle special cases first.
    // Check the strides, and modify them if needed.
    if ( *rs == 1 && *cs == 1 )
    {
        // If both strides are unit, we are probably trying to create a
        // 1-by-n matrix in column-major order, or an m-by-1 matrix in
        // row-major order. We have decided to "reserve" the case where
        // rs == cs == 1 for scalars only, as having unit strides can
        // upset the BLAS error checking when attempting to induce a
        // row-major operation.
        if ( m > 1 && n == 1 )
        {
            // Set the column stride to indicate that this is an m-by-1
            // matrix (or vector) stored in column-major order. This is
            // necessary because, in some cases, we have to satisfy error
            // checking in the underlying BLAS library, which expects the
            // leading dimension to be set to at least m, even if it will
            // never be used for indexing since there is only one column
            // of data. Note that rs is already set to 1.
            *cs = m;
        }
        else if ( m == 1 && 1 < n )
        {
            // Set the row stride to indicate that this is a 1-by-n matrix
            // stored in row-major order. Note that cs is already set to 1.
            *rs = n;
        }
        else
        {
            // If m == n == 1, then we are dealing with a scalar. Since rs
            // and cs do not exceed m and n, we don't have to do anything.
        }
    }
}

Referenced by bl1_ccreate_contigm(), bl1_ccreate_contigmr(), bl1_ccreate_contigmt(), bl1_dcreate_contigm(), bl1_dcreate_contigmr(), bl1_dcreate_contigmt(), bl1_screate_contigm(), bl1_screate_contigmr(), bl1_screate_contigmt(), bl1_zcreate_contigm(), bl1_zcreate_contigmr(), and bl1_zcreate_contigmt().