table of contents
| potf2(3) | LAPACK | potf2(3) |
NAME¶
potf2 - potf2: triangular factor panel, level 2
SYNOPSIS¶
Functions¶
subroutine cpotf2 (uplo, n, a, lda, info)
CPOTF2 computes the Cholesky factorization of a symmetric/Hermitian
positive definite matrix (unblocked algorithm). subroutine dpotf2
(uplo, n, a, lda, info)
DPOTF2 computes the Cholesky factorization of a symmetric/Hermitian
positive definite matrix (unblocked algorithm). subroutine spotf2
(uplo, n, a, lda, info)
SPOTF2 computes the Cholesky factorization of a symmetric/Hermitian
positive definite matrix (unblocked algorithm). subroutine zpotf2
(uplo, n, a, lda, info)
ZPOTF2 computes the Cholesky factorization of a symmetric/Hermitian
positive definite matrix (unblocked algorithm).
Detailed Description¶
Function Documentation¶
subroutine cpotf2 (character uplo, integer n, complex, dimension( lda, * ) a, integer lda, integer info)¶
CPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblocked algorithm).
Purpose:
!> !> CPOTF2 computes the Cholesky factorization of a complex Hermitian !> positive definite matrix A. !> !> The factorization has the form !> A = U**H * U , if UPLO = 'U', or !> A = L * L**H, if UPLO = 'L', !> where U is an upper triangular matrix and L is lower triangular. !> !> This is the unblocked version of the algorithm, calling Level 2 BLAS. !>
Parameters
!> UPLO is CHARACTER*1 !> Specifies whether the upper or lower triangular part of the !> Hermitian matrix A is stored. !> = 'U': Upper triangular !> = 'L': Lower triangular !>
N
!> N is INTEGER !> The order of the matrix A. N >= 0. !>
A
!> A is COMPLEX array, dimension (LDA,N) !> On entry, the Hermitian matrix A. If UPLO = 'U', the leading !> n by n upper triangular part of A contains the upper !> triangular part of the matrix A, and the strictly lower !> triangular part of A is not referenced. If UPLO = 'L', the !> leading n by n lower triangular part of A contains the lower !> triangular part of the matrix A, and the strictly upper !> triangular part of A is not referenced. !> !> On exit, if INFO = 0, the factor U or L from the Cholesky !> factorization A = U**H *U or A = L*L**H. !>
LDA
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
INFO
!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -k, the k-th argument had an illegal value !> > 0: if INFO = k, the leading principal minor of order k !> is not positive, and the factorization could not be !> completed. !>
Author
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
subroutine dpotf2 (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, integer info)¶
DPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblocked algorithm).
Purpose:
!> !> DPOTF2 computes the Cholesky factorization of a real symmetric !> positive definite matrix A. !> !> The factorization has the form !> A = U**T * U , if UPLO = 'U', or !> A = L * L**T, if UPLO = 'L', !> where U is an upper triangular matrix and L is lower triangular. !> !> This is the unblocked version of the algorithm, calling Level 2 BLAS. !>
Parameters
!> UPLO is CHARACTER*1 !> Specifies whether the upper or lower triangular part of the !> symmetric matrix A is stored. !> = 'U': Upper triangular !> = 'L': Lower triangular !>
N
!> N is INTEGER !> The order of the matrix A. N >= 0. !>
A
!> A is DOUBLE PRECISION array, dimension (LDA,N) !> On entry, the symmetric matrix A. If UPLO = 'U', the leading !> n by n upper triangular part of A contains the upper !> triangular part of the matrix A, and the strictly lower !> triangular part of A is not referenced. If UPLO = 'L', the !> leading n by n lower triangular part of A contains the lower !> triangular part of the matrix A, and the strictly upper !> triangular part of A is not referenced. !> !> On exit, if INFO = 0, the factor U or L from the Cholesky !> factorization A = U**T *U or A = L*L**T. !>
LDA
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
INFO
!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -k, the k-th argument had an illegal value !> > 0: if INFO = k, the leading principal minor of order k !> is not positive, and the factorization could not be !> completed. !>
Author
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
subroutine spotf2 (character uplo, integer n, real, dimension( lda, * ) a, integer lda, integer info)¶
SPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblocked algorithm).
Purpose:
!> !> SPOTF2 computes the Cholesky factorization of a real symmetric !> positive definite matrix A. !> !> The factorization has the form !> A = U**T * U , if UPLO = 'U', or !> A = L * L**T, if UPLO = 'L', !> where U is an upper triangular matrix and L is lower triangular. !> !> This is the unblocked version of the algorithm, calling Level 2 BLAS. !>
Parameters
!> UPLO is CHARACTER*1 !> Specifies whether the upper or lower triangular part of the !> symmetric matrix A is stored. !> = 'U': Upper triangular !> = 'L': Lower triangular !>
N
!> N is INTEGER !> The order of the matrix A. N >= 0. !>
A
!> A is REAL array, dimension (LDA,N) !> On entry, the symmetric matrix A. If UPLO = 'U', the leading !> n by n upper triangular part of A contains the upper !> triangular part of the matrix A, and the strictly lower !> triangular part of A is not referenced. If UPLO = 'L', the !> leading n by n lower triangular part of A contains the lower !> triangular part of the matrix A, and the strictly upper !> triangular part of A is not referenced. !> !> On exit, if INFO = 0, the factor U or L from the Cholesky !> factorization A = U**T *U or A = L*L**T. !>
LDA
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
INFO
!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -k, the k-th argument had an illegal value !> > 0: if INFO = k, the leading principal minor of order k !> is not positive, and the factorization could not be !> completed. !>
Author
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
subroutine zpotf2 (character uplo, integer n, complex*16, dimension( lda, * ) a, integer lda, integer info)¶
ZPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblocked algorithm).
Purpose:
!> !> ZPOTF2 computes the Cholesky factorization of a complex Hermitian !> positive definite matrix A. !> !> The factorization has the form !> A = U**H * U , if UPLO = 'U', or !> A = L * L**H, if UPLO = 'L', !> where U is an upper triangular matrix and L is lower triangular. !> !> This is the unblocked version of the algorithm, calling Level 2 BLAS. !>
Parameters
!> UPLO is CHARACTER*1 !> Specifies whether the upper or lower triangular part of the !> Hermitian matrix A is stored. !> = 'U': Upper triangular !> = 'L': Lower triangular !>
N
!> N is INTEGER !> The order of the matrix A. N >= 0. !>
A
!> A is COMPLEX*16 array, dimension (LDA,N) !> On entry, the Hermitian matrix A. If UPLO = 'U', the leading !> n by n upper triangular part of A contains the upper !> triangular part of the matrix A, and the strictly lower !> triangular part of A is not referenced. If UPLO = 'L', the !> leading n by n lower triangular part of A contains the lower !> triangular part of the matrix A, and the strictly upper !> triangular part of A is not referenced. !> !> On exit, if INFO = 0, the factor U or L from the Cholesky !> factorization A = U**H *U or A = L*L**H. !>
LDA
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>
INFO
!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -k, the k-th argument had an illegal value !> > 0: if INFO = k, the leading principal minor of order k !> is not positive, and the factorization could not be !> completed. !>
Author
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Author¶
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