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SOLVTYP |
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SOLVTYP |
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»Click here to display Table of Contents«
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SOLVTYP |
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SOLVTYP |
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SOLVTYP – Solver Selection for Static, Dynamic Analysis and Geometric Nonlinear Implicit Analysis (via RADIOSS Integration)
This bulk data entry can be used to define the solver type to be used for static, dynamic analysis and geometric nonlinear implicit analysis.
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SOLVTYP |
SID |
SOLVER |
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Continuation line for SOLVER = PCG, MIXED and AUTO
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PCON |
MAXIT |
ITOL |
TOL |
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Continuation line for SOLVER = MUMPS
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ORDM |
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Field |
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SID |
Unique set identification number. No default (Integer > 0) |
SOLVER |
Indicates the solver to be used. See comments 2, 3 and 4. BCS – Boeing Solver (direct solver). MUMPS – MUMPS Solver (direct solver). PCG - Preconditioned Conjugate Gradient (iterative solver). MIXED – Mixed solver using both BCS and PCG. AUTO – Automatically selects between BCS and PCG. Default = BCS - for linear static analysis and geometric nonlinear implicit dynamic analysis (ANALYSIS = IMPDYN); Default = MUMPS - for nonlinear static and nonlinear transient analysis |
PCON |
Indicates the type of pre-conditioner to be used. NO - No Pre-conditioner DJ - Diagonal Jacobi ICH - Incomplete Cholesky SICH - Stabilized Incomplete Cholesky FAI - Factored Approximate Inverse Default = FAI (Character) |
MAXIT |
Maximum number of iterations Default = Number of degrees-of-freedom of the system (Integer > 0 or blank) |
ITOL |
Convergence criteria for preconditioned iterative solver. RROM - Relative residual of original matrices ||r|| < TOL * ||b|| RRPM1 - Relative residual of preconditioned matrices ||r|| < TOL * ||b|| RRPM2 - Relative residual of preconditioned matrices ||r|| < TOL * ||A|| * ||x|| If the solver solves Ax = b, the residual is r = Ax - b. Default = RROM (Character) |
TOL |
Convergence tolerance. Default = 1.0e-5 for ITOL = RROM, RRPM1 or |
ORDM |
Ordering method for the MUMPS solver (see comment 8). AMD – Approximate minimum degree method (AMD) PORD – PORD package - provides better performance for a shell-type model METIS – METIS package SCOTCH - SCOTCH package (only available on Linux platform) PTSCOTCH - PTSCOTCH package (only available on Linux platform) AUTO – Automatically selects the appropriate ordering method Default = AUTO (Character) |
| 1. | SOLVTYP bulk data must be referenced by a SOLVTYP subcase statement. It only applies to static and dynamic subcases (and Implicit Dynamic Analysis via RADIOSS integration (ANALYSIS=IMPDYN)). |
| 2. | In optimization of linear static subcases, if iterative solver is selected, and if the responses DRESP1, RTYPE = DISP, LAMA, STRESS, STRAIN, CSTRESS, CSTRAIN, CFAILURE, or FORCE are present the solver is automatically reverted to the direct solver. |
| 3. | MUMPS “Multifrontal Massively Parallel sparse direct Solver” is the default non-symmetric solver for nonlinear static and nonlinear transient analysis (with or without frictional contact); it is also available as an optional symmetric solver for linear static runs. MUMPS is SMP and SPMD parallelized. Generally, MUMPS performance is similar to or better than the performance of BCS, especially for 2D models. |
For more details, see http://graal.ens-lyon.fr/MUMPS/index.php?page=home
| 4. | For an overview of default settings and options for the SOLVER field, see Table 1 in the User's Guide. |
| 5. | The iterative solver is a preconditioned conjugate gradient solver. A Factored Approximate Inverse Preconditioner is the default method. This solver is also SMP parallelized. |
| 6. | The performance of the iterative solver depends on the conditioning of the stiffness matrix. For compact solid models, the iterative solver may perform considerably better than the direct solver in terms of memory usage and elapsed times for a single linear static subcase. In the case of multiple linear static subcases, the iterative solver may perform worse than the direct solver. The breakeven point is at about 4-6 subcases. The performance depends on model, hardware, operating system, and potentially the system load. The performance may be below expectations on Itanium-based computers. |
| 7. | When the automatic solver option (SOLVER = AUTO) has been chosen, PCG is used first, the solver will be changed automatically to direct solver (BCS) if PCG performance is estimated slower than direct solver. In this case, direct solver will be used for the remainder of the run. |
| 8. | For further information about the MUMPS solver ordering method (ORDM) options, refer to the MUMPS 4.10 manual. |
| 9. | The SOLVTYP bulk and subcase data pair can be used in a Normal Modes Analysis model to select the direct solver (MUMPS/BCS) used for the solution of the internal linear shift for Lanczos runs. The SOLVTYP bulk and subcase data pair can also be used to specify the solver (MUMPS/BCS/PCG) used for Resvec calculation in Modal Frequency Response Analysis subcases. If you wish to select different solvers for the internal linear shift of the Lanczos eigenvalue solution and for the Resvec calculation in the Frequency Response solution, you can split the MFREQ subcase into two different subcases (Normal Modes subcase + Modal FRF subcase) with different SOLVTYP subcase and bulk data pairs in each subcase. The SOLVTYP bulk and subcase data pair can also be used in Buckling Analysis and Direct Frequency Response Analysis subcases. |
| 10. | This card is represented as a loadcollector in HyperMesh. |
See Also:
