Man page - pttrs(3)

Packages contains this manual

Manual

pttrs

NAME
SYNOPSIS
Functions
Detailed Description
Function Documentation
subroutine cpttrs (character uplo, integer n, integer nrhs, real,dimension( * ) d, complex, dimension( * ) e, complex, dimension( ldb, *) b, integer ldb, integer info)
subroutine dpttrs (integer n, integer nrhs, double precision, dimension( *) d, double precision, dimension( * ) e, double precision, dimension(ldb, * ) b, integer ldb, integer info)
subroutine spttrs (integer n, integer nrhs, real, dimension( * ) d, real,dimension( * ) e, real, dimension( ldb, * ) b, integer ldb, integerinfo)
subroutine zpttrs (character uplo, integer n, integer nrhs, doubleprecision, dimension( * ) d, complex*16, dimension( * ) e, complex*16,dimension( ldb, * ) b, integer ldb, integer info)
Author

NAME

pttrs - pttrs: triangular solve using factor

SYNOPSIS

Functions

subroutine cpttrs (uplo, n, nrhs, d, e, b, ldb, info)
CPTTRS
subroutine dpttrs (n, nrhs, d, e, b, ldb, info)
DPTTRS
subroutine spttrs (n, nrhs, d, e, b, ldb, info)
SPTTRS
subroutine zpttrs (uplo, n, nrhs, d, e, b, ldb, info)
ZPTTRS

Detailed Description

Function Documentation

subroutine cpttrs (character uplo, integer n, integer nrhs, real,dimension( * ) d, complex, dimension( * ) e, complex, dimension( ldb, *) b, integer ldb, integer info)

CPTTRS

Purpose:

CPTTRS solves a tridiagonal system of the form
A * X = B
using the factorization A = U**H*D*U or A = L*D*L**H computed by CPTTRF.
D is a diagonal matrix specified in the vector D, U (or L) is a unit
bidiagonal matrix whose superdiagonal (subdiagonal) is specified in
the vector E, and X and B are N by NRHS matrices.

Parameters

UPLO

UPLO is CHARACTER*1
Specifies the form of the factorization and whether the
vector E is the superdiagonal of the upper bidiagonal factor
U or the subdiagonal of the lower bidiagonal factor L.
= ā€™Uā€™: A = U**H*D*U, E is the superdiagonal of U
= ā€™Lā€™: A = L*D*L**H, E is the subdiagonal of L

N

N is INTEGER
The order of the tridiagonal matrix A. N >= 0.

NRHS

NRHS is INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.

D

D is REAL array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
factorization A = U**H*D*U or A = L*D*L**H.

E

E is COMPLEX array, dimension (N-1)
If UPLO = ā€™Uā€™, the (n-1) superdiagonal elements of the unit
bidiagonal factor U from the factorization A = U**H*D*U.
If UPLO = ā€™Lā€™, the (n-1) subdiagonal elements of the unit
bidiagonal factor L from the factorization A = L*D*L**H.

B

B is COMPLEX array, dimension (LDB,NRHS)
On entry, the right hand side vectors B for the system of
linear equations.
On exit, the solution vectors, X.

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.

subroutine dpttrs (integer n, integer nrhs, double precision, dimension( *) d, double precision, dimension( * ) e, double precision, dimension(ldb, * ) b, integer ldb, integer info)

DPTTRS

Purpose:

DPTTRS solves a tridiagonal system of the form
A * X = B
using the L*D*L**T factorization of A computed by DPTTRF. D is a
diagonal matrix specified in the vector D, L is a unit bidiagonal
matrix whose subdiagonal is specified in the vector E, and X and B
are N by NRHS matrices.

Parameters

N

N is INTEGER
The order of the tridiagonal matrix A. N >= 0.

NRHS

NRHS is INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.

D

D is DOUBLE PRECISION array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
L*D*L**T factorization of A.

E

E is DOUBLE PRECISION array, dimension (N-1)
The (n-1) subdiagonal elements of the unit bidiagonal factor
L from the L*D*L**T factorization of A. E can also be regarded
as the superdiagonal of the unit bidiagonal factor U from the
factorization A = U**T*D*U.

B

B is DOUBLE PRECISION array, dimension (LDB,NRHS)
On entry, the right hand side vectors B for the system of
linear equations.
On exit, the solution vectors, X.

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.

subroutine spttrs (integer n, integer nrhs, real, dimension( * ) d, real,dimension( * ) e, real, dimension( ldb, * ) b, integer ldb, integerinfo)

SPTTRS

Purpose:

SPTTRS solves a tridiagonal system of the form
A * X = B
using the L*D*L**T factorization of A computed by SPTTRF. D is a
diagonal matrix specified in the vector D, L is a unit bidiagonal
matrix whose subdiagonal is specified in the vector E, and X and B
are N by NRHS matrices.

Parameters

N

N is INTEGER
The order of the tridiagonal matrix A. N >= 0.

NRHS

NRHS is INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.

D

D is REAL array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
L*D*L**T factorization of A.

E

E is REAL array, dimension (N-1)
The (n-1) subdiagonal elements of the unit bidiagonal factor
L from the L*D*L**T factorization of A. E can also be regarded
as the superdiagonal of the unit bidiagonal factor U from the
factorization A = U**T*D*U.

B

B is REAL array, dimension (LDB,NRHS)
On entry, the right hand side vectors B for the system of
linear equations.
On exit, the solution vectors, X.

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.

subroutine zpttrs (character uplo, integer n, integer nrhs, doubleprecision, dimension( * ) d, complex*16, dimension( * ) e, complex*16,dimension( ldb, * ) b, integer ldb, integer info)

ZPTTRS

Purpose:

ZPTTRS solves a tridiagonal system of the form
A * X = B
using the factorization A = U**H *D* U or A = L*D*L**H computed by ZPTTRF.
D is a diagonal matrix specified in the vector D, U (or L) is a unit
bidiagonal matrix whose superdiagonal (subdiagonal) is specified in
the vector E, and X and B are N by NRHS matrices.

Parameters

UPLO

UPLO is CHARACTER*1
Specifies the form of the factorization and whether the
vector E is the superdiagonal of the upper bidiagonal factor
U or the subdiagonal of the lower bidiagonal factor L.
= ā€™Uā€™: A = U**H *D*U, E is the superdiagonal of U
= ā€™Lā€™: A = L*D*L**H, E is the subdiagonal of L

N

N is INTEGER
The order of the tridiagonal matrix A. N >= 0.

NRHS

NRHS is INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.

D

D is DOUBLE PRECISION array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
factorization A = U**H *D*U or A = L*D*L**H.

E

E is COMPLEX*16 array, dimension (N-1)
If UPLO = ā€™Uā€™, the (n-1) superdiagonal elements of the unit
bidiagonal factor U from the factorization A = U**H*D*U.
If UPLO = ā€™Lā€™, the (n-1) subdiagonal elements of the unit
bidiagonal factor L from the factorization A = L*D*L**H.

B

B is COMPLEX*16 array, dimension (LDB,NRHS)
On entry, the right hand side vectors B for the system of
linear equations.
On exit, the solution vectors, X.

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.

Author

Generated automatically by Doxygen for LAPACK from the source code.