HP MLIB User's Guide Vol. 2 7th Ed.

936 HP MLIB User’s Guide
DSLEOP Select reordering scheme
For matrix structure input by elements, columns, and
finite elements, use one of the following four options:
order = ’MMD’ or ’mmd’
Use the Multiple Minimum Degree
ordering.
order = ’NOT’ or ’not’
No internal reordering is performed;
the original ordering is used in all
phases of the solver.
order = ’MUL’ or ’mul’
Use the Multilevel Nested Dissection
ordering. This ordering is very
effective for certain applications, such
as matrices from linear programming
(LP) problem and 3-D finite element
problems using brick elements.
order = ’OPT’ or ’opt’
Use the optimal ordering. This option
runs both the MMD and Multilevel
Nested Dissection orderings, and
chooses the one which produces the
smaller number of fill-ins in the
numerical factorization.
Updated global
Global communications array for this problem. This
array must be passed, untouched by the user, to
successive subroutines in this package.
Output ier
Status response:
ier = 0
Normal return.
ier = −1100
Incorrect processing path; should be
called before DSLEOR.
ier = −1101
Invalid value for order.
Notes Actual character arguments in a subroutine call may be longer than
corresponding dummy arguments. Therefore, readability of the CALL
statement may be improved by coding the order argument as ’MMD
Reordering’ or ’not reordering’.