naginterfaces.library.sparse.direct_real_gen_diag¶
- naginterfaces.library.sparse.direct_real_gen_diag(icolzp, a, iprm, il, lval, iu, uval)[source]¶
direct_real_gen_diag
computes the reciprocal pivot growth factor of an factorization of a real sparse matrix in compressed column (Harwell–Boeing) format.For full information please refer to the NAG Library document for f11mm
https://support.nag.com/numeric/nl/nagdoc_30.2/flhtml/f11/f11mmf.html
- Parameters
- icolzpint, array-like, shape
The new column index array of sparse matrix . See the F11 Introduction.
- afloat, array-like, shape
The array of nonzero values in the sparse matrix .
- iprmint, array-like, shape
The column permutation which defines , the row permutation which defines , plus associated data structures as computed by
direct_real_gen_lu()
.- ilint, array-like, shape
Records the sparsity pattern of matrix as computed by
direct_real_gen_lu()
.- lvalfloat, array-like, shape
Records the nonzero values of matrix and some nonzero values of matrix as computed by
direct_real_gen_lu()
.- iuint, array-like, shape
Records the sparsity pattern of matrix as computed by
direct_real_gen_lu()
.- uvalfloat, array-like, shape
Records some nonzero values of matrix as computed by
direct_real_gen_lu()
.
- Returns
- rpgfloat
The reciprocal pivot growth factor . If the reciprocal pivot growth factor is much less than , the stability of the factorization may be poor.
- Raises
- NagValueError
- (errno )
On entry, .
Constraint: .
- (errno )
Incorrect column permutations in array .
- Notes
direct_real_gen_diag
computes the reciprocal pivot growth factor from the columns and of an factorization of the matrix , where is a row permutation matrix, is a column permutation matrix, is unit lower triangular and is upper triangular as computed bydirect_real_gen_lu()
.