F11MMF computes the reciprocal pivot growth factor
maxjAj∞/Uj∞ from the columns
Aj and
Uj of an
LU
factorization of the matrix
A,
Pr
A
Pc
=
LU
where
Pr is a row permutation matrix,
Pc is a column permutation matrix,
L is unit lower triangular and
U is upper triangular as computed by
F11MEF.
None.
If on entry
IFAIL=0 or
-1, explanatory error messages are output on the current error message unit (as defined by
X04AAF).
Not applicable.
If the reciprocal pivot growth factor,
RPG, is much less than
1, then the factorization of the matrix
A could be poor. This means that using the factorization to obtain solutions to a linear system, forward error bounds and estimates of the condition number could be unreliable. Consider increasing the
THRESH parameter in the call to
F11MEF.
To compute the reciprocal pivot growth for the factorization of the matrix
A, where
In this case, it should be equal to
1.0.