TESTING/LIN/slavsp.f(3) | Library Functions Manual | TESTING/LIN/slavsp.f(3) |
NAME
TESTING/LIN/slavsp.f
SYNOPSIS
Functions/Subroutines
subroutine slavsp (uplo, trans, diag, n, nrhs, a, ipiv, b,
ldb, info)
SLAVSP
Function/Subroutine Documentation
subroutine slavsp (character uplo, character trans, character diag, integer n, integer nrhs, real, dimension( * ) a, integer, dimension( * ) ipiv, real, dimension( ldb, * ) b, integer ldb, integer info)
SLAVSP
Purpose:
SLAVSP performs one of the matrix-vector operations x := A*x or x := A'*x, where x is an N element vector and A is one of the factors from the block U*D*U' or L*D*L' factorization computed by SSPTRF. If TRANS = 'N', multiplies by U or U * D (or L or L * D) If TRANS = 'T', multiplies by U' or D * U' (or L' or D * L' ) If TRANS = 'C', multiplies by U' or D * U' (or L' or D * L' )
Parameters
UPLO
UPLO is CHARACTER*1 Specifies whether the factor stored in A is upper or lower triangular. = 'U': Upper triangular = 'L': Lower triangular
TRANS
TRANS is CHARACTER*1 Specifies the operation to be performed: = 'N': x := A*x = 'T': x := A'*x = 'C': x := A'*x
DIAG
DIAG is CHARACTER*1 Specifies whether or not the diagonal blocks are unit matrices. If the diagonal blocks are assumed to be unit, then A = U or A = L, otherwise A = U*D or A = L*D. = 'U': Diagonal blocks are assumed to be unit matrices. = 'N': Diagonal blocks are assumed to be non-unit matrices.
N
N is INTEGER The number of rows and columns of the matrix A. N >= 0.
NRHS
NRHS is INTEGER The number of right hand sides, i.e., the number of vectors x to be multiplied by A. NRHS >= 0.
A
A is REAL array, dimension (N*(N+1)/2) The block diagonal matrix D and the multipliers used to obtain the factor U or L, stored as a packed triangular matrix as computed by SSPTRF.
IPIV
IPIV is INTEGER array, dimension (N) The pivot indices from SSPTRF.
B
B is REAL array, dimension (LDB,NRHS) On entry, B contains NRHS vectors of length N. On exit, B is overwritten with the product A * B.
LDB
LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N).
INFO
INFO is INTEGER = 0: successful exit < 0: if INFO = -k, the k-th argument had an illegal value
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 128 of file slavsp.f.
Author
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