#include <Amesos_BaseSolver.h>
Inheritance diagram for Amesos_BaseSolver:
Public Member Functions  
Destructor.  
virtual  ~Amesos_BaseSolver () 
Destructor.  
Atribute set methods.  
virtual int  SetUseTranspose (bool UseTranspose)=0 
If set true, X will be set to the solution of A^{T} X = B (not A X = B).  
virtual int  SetParameters (Teuchos::ParameterList &ParameterList)=0 
Updates internal variables.  
Mathematical functions.  
virtual int  SymbolicFactorization ()=0 
Performs SymbolicFactorization on the matrix A.  
virtual int  NumericFactorization ()=0 
Performs NumericFactorization on the matrix A.  
virtual int  Solve ()=0 
Solves A X = B (or A^{T} x = B).  
Atribute access functions  
virtual const Epetra_LinearProblem *  GetProblem () const =0 
Returns the Epetra_LinearProblem.  
virtual bool  MatrixShapeOK () const =0 
Returns true if the solver can handle this matrix shape.  
virtual bool  UseTranspose () const =0 
Returns the current UseTranspose setting.  
virtual const Epetra_Comm &  Comm () const =0 
Returns a pointer to the Epetra_Comm communicator associated with this operator. 
The Amesos_BaseSolver class is a pure virtual class (specifies interface only) that enables the use of realvalued doubleprecision direct sparse solvers. Every Amesos class named Amesos_SolverName implements Amesos_BaseSolver.
The basic calling sequence solves A x = b or A^{T} x = b without specifying how A has changed between each call to Solve().
Epetra_LinearProblem Problem(A,X,B); Amesos_SolverName Solver(Problem); Problem.SetTranspose( false ); while( ... ) {
Code which may change A or B
Solver.SymbolicFactorization() ; Solver.NumericFactorization() ; Solver.Solve() ;
The following calling sequence performs multiple solves of A x = b or A^{T} x = b in cases where the nonzero structure of A remains unchanged between each call to Solve().
Epetra_LinearProblem Problem(A,X,B); Amesos_SolverName Solver(Problem); Problem.SetTranspose( false ); Solver.SymbolicFactorization() ; while( ... ) {
Code which may change B or the nonzero values (but not the nonzero structure) of A
Solver.NumericFactorization() ; Solver.Solve() ;
The following calling sequence performs multiple solves of A x = b or A^{T} x = b provided that the change to A is small.
Epetra_LinearProblem Problem(A,X,B); Amesos_SolverName Solver(Problem); Problem.SetTranspose( false ); Solver.NumericFactorization() ; while( ... ) {
Code which may change A slightly
Solver.PivotlessRefactorization() ; Solver.Solve() ;
The following calling sequence performs multiple solves of A x = b or A^{T} x = b provided that A remains unchanged between each call to Solve().
Epetra_LinearProblem Problem(A,X,B); Amesos_SolverName Solver(Problem); Problem.SetTranspose( false ); Solver.NumericFactorization() ; while( ... ) {
Code which may change B but not A
Solver.Solve() ;
Every Amesos_SolverName class should accept an Epetra_LinearProblem
Four mathematical methods are defined in the base class Amesos_BaseSolver: SymbolicFactorization(), NumericFactorization(), PivotelssRefactorization() and Solve().
Different concrete classes, each based on a different third party solver, will have different performance characteristics and will accept different parameters.
In the basic calling sequence (no calls to SymbolicFactorization() or NumericFactorization()), the underlying matrix can be modified between any two calls to Solve()  any class implementing this interface must perform the solve based on the values in the matrix at the time that Solve() is called.
Once SymbolicFactorization() has been called, classes implementing this interface may assume that any change made to the nonzero structure of the underlying matrix will be accompanied by a call to SymbolicFactorization() prior to a subsequent call to NumericFactorization or Solve().
Parameters can be changed or added at any time by calling SetParameters(ParamList) with the new parameters specified in ParamList.
It is left to the user to be sure that changes made to the parameters are appropriate for the concrete class that they are using.
Examples of appropriate changes in parameters include:
Examples of inappropriate changes in parameters include:
Solver.NumericFactorization(); Solver.getList()>set("DropTolerance",.001); Solver.Solve();
Any class implementing Amesos_BaseSolver should handle calls to SetTranspose() at any point. Some third party libraries are able to solve A^{T} x = b and Ax = b using the same factorization. Others will require a new factorization anytime that a call to SetTranspose() changes the intended solve from A^{T} x = b to Ax = b or viceversa.
The following is a list of performance guidelines that classes which implement the Amesos_BaseSolver class are expected to maintain.
For serial codes, no more than one extra copy of the original matrix should be required. Except that some codes require matrix transpostion which requires additional copies of the input matrix.
For distributed memory codes, no serial copies of the original matrix should be required.
Communication should be kept to a minimum, storing data on the process where it will be used where possible.
Theta(n) compuational requirements (i.e. those which grow at least linearly with the number of rows in the matrix) should not be repeated unnecessarily. Constant order, i.e. O(1), computational tasks may be repeated.
Failures should be caught either by EPETRA_CHK_ERR() or through calls to assert.
Because we do not check to see if a matrix has changed between the call to SymbolicFactorization() and the call to NumericFactorization(), it is possible that a change to the matrix will cause a potentially catastrophic error.
See amesos/configuration for a list of files added or modified to create the Amesos_Umfpack concrete class.

Returns true if the solver can handle this matrix shape. Returns true if the matrix shape is one that the underlying sparse direct solver can handle. Classes that work only on square matrices should return false for rectangular matrices. Classes that work only on symmetric matrices whould return false for nonsymmetric matrices. Implemented in Amesos_Btf, Amesos_Dscpack, Amesos_Klu, Amesos_Lapack, Amesos_Merikos, Amesos_Klu, Amesos_Mumps, Amesos_Scalapack, Amesos_Superlu, Amesos_Superludist, and Amesos_Umfpack. 

Performs NumericFactorization on the matrix A. In addition to performing numeric factorization on the matrix A, the call to NumericFactorization() implies that no change will be made to the underlying matrix without a subsequent call to NumericFactorization(). <br >Preconditions:
<br >Postconditions:
Implemented in Amesos_Btf, Amesos_Dscpack, Amesos_Klu, Amesos_Lapack, Amesos_Merikos, Amesos_Klu, Amesos_Mumps, Amesos_Scalapack, Amesos_Superlu, Amesos_Superludist, and Amesos_Umfpack. 

Updates internal variables. <br >Preconditions:
<br >Postconditions:
Implemented in Amesos_Btf, Amesos_Dscpack, Amesos_Klu, Amesos_Lapack, Amesos_Merikos, Amesos_Klu, Amesos_Mumps, Amesos_Scalapack, Amesos_Superlu, Amesos_Superludist, and Amesos_Umfpack. 

If set true, X will be set to the solution of A^{T} X = B (not A X = B). If the implementation of this interface does not support transpose use, this method should return a value of 1. <br >Preconditions:
<br >Postconditions:
Implemented in Amesos_Btf, Amesos_Dscpack, Amesos_Klu, Amesos_Lapack, Amesos_Merikos, Amesos_Klu, Amesos_Mumps, Amesos_Scalapack, Amesos_Superlu, Amesos_Superludist, and Amesos_Umfpack. 

Solves A X = B (or A^{T} x = B). <br >Preconditions:
<br >Postconditions:
Implemented in Amesos_Btf, Amesos_Dscpack, Amesos_Klu, Amesos_Lapack, Amesos_Merikos, Amesos_Klu, Amesos_Mumps, Amesos_Scalapack, Amesos_Superlu, Amesos_Superludist, and Amesos_Umfpack. 

Performs SymbolicFactorization on the matrix A. In addition to performing symbolic factorization on the matrix A, the call to SymbolicFactorization() implies that no change will be made to the nonzero structure of the underlying matrix without a subsequent call to SymbolicFactorization(). <br >Preconditions:
<br >Postconditions:
Implemented in Amesos_Btf, Amesos_Dscpack, Amesos_Klu, Amesos_Lapack, Amesos_Merikos, Amesos_Klu, Amesos_Mumps, Amesos_Scalapack, Amesos_Superlu, Amesos_Superludist, and Amesos_Umfpack. 