pptrs
pptrs: triangular solve using factor
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pptrs: triangular solve using factor
subroutine cpptrs (uplo, n, nrhs, ap, b, ldb, info)
CPPTRS subroutine dpptrs (uplo, n, nrhs, ap, b, ldb, info)
DPPTRS subroutine spptrs (uplo, n, nrhs, ap, b, ldb, info)
SPPTRS subroutine zpptrs (uplo, n, nrhs, ap, b, ldb, info)
ZPPTRS
CPPTRS
Purpose:
!> !> CPPTRS solves a system of linear equations A*X = B with a Hermitian !> positive definite matrix A in packed storage using the Cholesky !> factorization A = U**H*U or A = L*L**H computed by CPPTRF. !>
Parameters
!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored. !>
N
!> N is INTEGER !> The order of the 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. !>
AP
!> AP is COMPLEX array, dimension (N*(N+1)/2) !> The triangular factor U or L from the Cholesky factorization !> A = U**H*U or A = L*L**H, packed columnwise in a linear !> array. The j-th column of U or L is stored in the array AP !> as follows: !> if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j; !> if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n. !>
B
!> B is COMPLEX array, dimension (LDB,NRHS) !> On entry, the right hand side matrix B. !> On exit, the solution matrix 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 = -i, the i-th argument had an illegal value !>
Author
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
DPPTRS
Purpose:
!> !> DPPTRS solves a system of linear equations A*X = B with a symmetric !> positive definite matrix A in packed storage using the Cholesky !> factorization A = U**T*U or A = L*L**T computed by DPPTRF. !>
Parameters
!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored. !>
N
!> N is INTEGER !> The order of the 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. !>
AP
!> AP is DOUBLE PRECISION array, dimension (N*(N+1)/2) !> The triangular factor U or L from the Cholesky factorization !> A = U**T*U or A = L*L**T, packed columnwise in a linear !> array. The j-th column of U or L is stored in the array AP !> as follows: !> if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j; !> if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n. !>
B
!> B is DOUBLE PRECISION array, dimension (LDB,NRHS) !> On entry, the right hand side matrix B. !> On exit, the solution matrix 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 = -i, the i-th argument had an illegal value !>
Author
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
SPPTRS
Purpose:
!> !> SPPTRS solves a system of linear equations A*X = B with a symmetric !> positive definite matrix A in packed storage using the Cholesky !> factorization A = U**T*U or A = L*L**T computed by SPPTRF. !>
Parameters
!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored. !>
N
!> N is INTEGER !> The order of the 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. !>
AP
!> AP is REAL array, dimension (N*(N+1)/2) !> The triangular factor U or L from the Cholesky factorization !> A = U**T*U or A = L*L**T, packed columnwise in a linear !> array. The j-th column of U or L is stored in the array AP !> as follows: !> if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j; !> if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n. !>
B
!> B is REAL array, dimension (LDB,NRHS) !> On entry, the right hand side matrix B. !> On exit, the solution matrix 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 = -i, the i-th argument had an illegal value !>
Author
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
ZPPTRS
Purpose:
!> !> ZPPTRS solves a system of linear equations A*X = B with a Hermitian !> positive definite matrix A in packed storage using the Cholesky !> factorization A = U**H * U or A = L * L**H computed by ZPPTRF. !>
Parameters
!> UPLO is CHARACTER*1 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored. !>
N
!> N is INTEGER !> The order of the 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. !>
AP
!> AP is COMPLEX*16 array, dimension (N*(N+1)/2) !> The triangular factor U or L from the Cholesky factorization !> A = U**H * U or A = L * L**H, packed columnwise in a linear !> array. The j-th column of U or L is stored in the array AP !> as follows: !> if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j; !> if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n. !>
B
!> B is COMPLEX*16 array, dimension (LDB,NRHS) !> On entry, the right hand side matrix B. !> On exit, the solution matrix 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 = -i, the i-th argument had an illegal value !>
Author
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
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