Subsections

MA57 Linear Solver


ma57_pivtol:

Pivot tolerance for the linear solver MA57.
A smaller number pivots for sparsity, a larger number pivots for stability. This option is only available if Ipopt has been compiled with MA57. The valid range for this real option is $ 0 < {\tt ma57\_pivtol } < 1$ and its default value is $ 1 \cdot 10^{-08}$.


ma57_pivtolmax:

Maximum pivot tolerance for the linear solver MA57.
Ipopt may increase pivtol as high as ma57_pivtolmax to get a more accurate solution to the linear system. This option is only available if Ipopt has been compiled with MA57. The valid range for this real option is $ 0 < {\tt ma57\_pivtolmax } < 1$ and its default value is $ 0.0001$.


ma57_pre_alloc:

Safety factor for work space memory allocation for the linear solver MA57.
If 1 is chosen, the suggested amount of work space is used. However, choosing a larger number might avoid reallocation if the suggest values do not suffice. This option is only available if Ipopt has been compiled with MA57. The valid range for this real option is $ 1 \le {\tt ma57\_pre\_alloc } < {\tt +inf}$ and its default value is $ 1.05$.


ma57_pivot_order:

Controls pivot order in MA57
This is ICNTL(6) in MA57. The valid range for this integer option is $ 0 \le {\tt ma57\_pivot\_order } \le 5$ and its default value is $ 5$.


ma57_automatic_scaling:

Controls MA57 automatic scaling
This option controls the internal scaling option of MA57. For higher reliability of the MA57 solver, you may want to set this option to yes. This is ICNTL(15) in MA57. The default value for this string option is "no".
Possible values:


ma57_block_size:

Controls block size used by Level 3 BLAS in MA57BD
This is ICNTL(11) in MA57. The valid range for this integer option is $ 1 \le {\tt ma57\_block\_size } < {\tt +inf}$ and its default value is $ 16$.


ma57_node_amalgamation:

Node amalgamation parameter
This is ICNTL(12) in MA57. The valid range for this integer option is $ 1 \le {\tt ma57\_node\_amalgamation } < {\tt +inf}$ and its default value is $ 16$.


ma57_small_pivot_flag:

If set to 1, then when small entries defined by CNTL(2) are detected they are removed and the corresponding pivots placed at the end of the factorization. This can be particularly efficient if the matrix is highly rank deficient.
This is ICNTL(16) in MA57. The valid range for this integer option is $ 0 \le {\tt ma57\_small\_pivot\_flag } \le 1$ and its default value is 0.