MA86 Linear Solver

ma86_print_level:

Debug printing level for the linear solver MA86
The valid range for this integer option is ${\tt -inf} < {\tt ma86\_print\_level } < {\tt +inf}$ and its default value is $-1$ .

ma86_nemin:

Node Amalgamation parameter
Two nodes in elimination tree are merged if result has fewer than ma86_nemin variables. The valid range for this integer option is $1 \le {\tt ma86\_nemin } < {\tt +inf}$ and its default value is $32$ .

ma86_order:

Controls type of ordering used by HSL_MA86
This option controls ordering for the solver HSL_MA86. The default value for this string option is "amd".
Possible values:

• auto: Try both AMD and MeTiS, pick best
• amd: Use the HSL_MC68 approximate minimum degree algorithm
• metis: Use the MeTiS nested dissection algorithm (if available)

ma86_scaling:

Controls scaling of matrix
This option controls scaling for the solver HSL_MA86. The default value for this string option is "mc64".
Possible values:

• none: Do not scale the linear system matrix
• mc64: Scale linear system matrix using MC64
• mc77: Scale linear system matrix using MC77 [1,3,0]

ma86_small:

Zero Pivot Threshold
Any pivot less than ma86_small is treated as zero. The valid range for this real option is $0 \le {\tt ma86\_small } < {\tt +inf}$ and its default value is $1 \cdot 10^{-20}$ .

ma86_static:

Static Pivoting Threshold
See MA86 documentation. Either ma86_static=0.0 or ma86_static>ma86_small. ma86_static=0.0 disables static pivoting. The valid range for this real option is $0 \le {\tt ma86\_static } < {\tt +inf}$ and its default value is 0 .

ma86_u:

Pivoting Threshold
See MA86 documentation. The valid range for this real option is $0 \le {\tt ma86\_u } \le 0.5$ and its default value is $1 \cdot 10^{-08}$ .

ma86_umax:

Maximum Pivoting Threshold
Maximum value to which u will be increased to improve quality. The valid range for this real option is $0 \le {\tt ma86\_umax } \le 0.5$ and its default value is $0.0001$ .