naginterfaces.library.sparse.real_gen_precon_ssor_solve¶
- naginterfaces.library.sparse.real_gen_precon_ssor_solve(trans, a, irow, icol, rdiag, omega, y, check='N')[source]¶
real_gen_precon_ssor_solve
solves a system of linear equations involving the preconditioning matrix corresponding to SSOR applied to a real sparse nonsymmetric matrix, represented in coordinate storage format.For full information please refer to the NAG Library document for f11dd
https://support.nag.com/numeric/nl/nagdoc_30.2/flhtml/f11/f11ddf.html
- Parameters
- transstr, length 1
Specifies whether or not the matrix is transposed.
is solved.
is solved.
- afloat, array-like, shape
The nonzero elements in the matrix , ordered by increasing row index, and by increasing column index within each row. Multiple entries for the same row and column indices are not permitted. The function
real_gen_sort()
may be used to order the elements in this way.- irowint, array-like, shape
The row indices of the nonzero elements supplied in array .
- icolint, array-like, shape
The column indices of the nonzero elements supplied in array .
- rdiagfloat, array-like, shape
The elements of the diagonal matrix , where is the diagonal part of .
- omegafloat
The relaxation parameter .
- yfloat, array-like, shape
The right-hand side vector .
- checkstr, length 1, optional
Specifies whether or not the CS representation of the matrix should be checked.
Checks are carried on the values of , , , and .
None of these checks are carried out.
See also Further Comments.
- Returns
- xfloat, ndarray, shape
The solution vector .
- Raises
- NagValueError
- (errno )
On entry, .
Constraint: or .
- (errno )
On entry, .
Constraint: or .
- (errno )
On entry, .
Constraint: .
- (errno )
On entry, and .
Constraint: .
- (errno )
On entry, .
Constraint: .
- (errno )
On entry, .
Constraint: .
- (errno )
On entry, the location () is a duplicate: .
- (errno )
On entry, is out of order: .
- (errno )
On entry, , and .
Constraint: and .
- (errno )
On entry, , and .
Constraint: and .
- (errno )
The matrix has no diagonal entry in row .
- Notes
real_gen_precon_ssor_solve
solves a system of linear equationsaccording to the value of the argument , where the matrix
corresponds to symmetric successive-over-relaxation (SSOR) (see Young (1971)) applied to a linear system , where is a real sparse nonsymmetric matrix stored in coordinate storage (CS) format (see the F11 Introduction).
In the definition of given above is the diagonal part of , is the strictly lower triangular part of , is the strictly upper triangular part of , and is a user-defined relaxation parameter.
It is envisaged that a common use of
real_gen_precon_ssor_solve
will be to carry out the preconditioning step required in the application ofreal_gen_basic_solver()
to sparse linear systems.real_gen_precon_ssor_solve
is also used for this purpose by the Black Box functionreal_gen_solve_jacssor()
.
- References
Young, D, 1971, Iterative Solution of Large Linear Systems, Academic Press, New York