pcgopt

Mapdl.pcgopt(lev_diff='', reduceio='', strmck='', wrtfull='', memory='', lm_key='', **kwargs)

Controls PCG solver options.

APDL Command: PCGOPT

Parameters
  • lev_diff – Indicates the level of difficulty of the analysis. Valid settings are AUTO or 0 (default), 1, 2, 3, 4, or 5. This option applies to both the PCG solver when used in static and full transient analyses and to the PCG Lanczos method in modal analyses. Use AUTO to let ANSYS automatically choose the proper level of difficulty for the model. Lower values (1 or 2) generally provide the best performance for well-conditioned problems. Values of 3 or 4 generally provide the best performance for ill-conditioned problems; however, higher values may increase the solution time for well-conditioned problems. Higher level-of-difficulty values typically require more memory. Using the highest value of 5 essentially performs a factorization of the global matrix (similar to the sparse solver) and may require a very large amount of memory. If necessary, use Memory to reduce the memory usage when using Lev_Diff = 5. Lev_Diff = 5 is generally recommended for small- to medium-sized problems when using the PCG Lanczos mode extraction method.

  • reduceio

    Controls whether the PCG solver will attempt to reduce I/O performed during equation solution:

    AUTO - Automatically chooses whether to reduce I/O or not (default).

    YES - Reduces I/O performed during equation solution in order to reduce total solver time.

    NO - Does NOT reduce I/O performed during equation solution.

  • strmck

    Controls whether or not a Sturm sequence check is performed:

    OFF - Does NOT perform Sturm sequence check (default).

    ON - Performs Sturm sequence check

  • wrtfull

    Controls whether or not the .FULL file is written.

    ON - Write .FULL file (default)

    OFF - Do not write .FULL file.

  • memory

    Controls whether to run using in-core or out-of-core mode when using Lev_Diff = 5.

    AUTO - Automatically chooses which mode to use (default).

    INCORE - Run using in-core mode.

    OOC - Run using out-of-core mode.

  • lm_key

    Controls use of the PCG solver for MPC184 Lagrange multiplier method elements. This option applies only to the PCG solver when used in static and full transient analyses.

    OFF - Do not use the PCG solver for the MPC184 Lagrange multiplier method (default).

    ON - Allow use of the PCG solver for the MPC184 Lagrange multiplier method.

Notes

ReduceIO works independently of the MSAVE command in the PCG solver. Setting ReduceIO to YES can significantly increase the memory usage in the PCG solver.

To minimize the memory used by the PCG solver with respect to the Lev_Diff option only, set Lev_Diff = 1 if you do not have sufficient memory to run the PCG solver with Lev_Diff = AUTO.

The MSAVE,ON command is not valid when using Lev_Diff = 5. In this case, the Lev_Diff value will automatically be reset to 2. The MSAVE,ON command is also not valid with the StrmCk option. In this case, StrmCk will be set to OFF.

Distributed ANSYS Restriction: The Memory option and the LM_Key option are not supported in Distributed ANSYS.