CPTTRS(3F) CPTTRS(3F)
CPTTRS  solve a system of linear equations A * X = B with a Hermitian
positive definite tridiagonal matrix A using the factorization A =
U**H*D*U or A = L*D*L**H computed by CPTTRF
SUBROUTINE CPTTRS( UPLO, N, NRHS, D, E, B, LDB, INFO )
CHARACTER UPLO
INTEGER INFO, LDB, N, NRHS
REAL D( * )
COMPLEX B( LDB, * ), E( * )
CPTTRS solves a system of linear equations A * X = B with a Hermitian
positive definite tridiagonal matrix A using the factorization A =
U**H*D*U or A = L*D*L**H computed by CPTTRF.
UPLO (input) CHARACTER*1
Specifies whether the superdiagonal or the subdiagonal of the
tridiagonal matrix A is stored and the form of the factorization:
= 'U': E is the superdiagonal of U, and A = U'*D*U;
= 'L': E is the subdiagonal of L, and A = L*D*L'. (The two
forms are equivalent if A is real.)
N (input) INTEGER
The order of the tridiagonal matrix A. N >= 0.
NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns of
the matrix B. NRHS >= 0.
D (input) REAL array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
factorization computed by CPTTRF.
E (input) COMPLEX array, dimension (N1)
The (n1) offdiagonal elements of the unit bidiagonal factor U
or L from the factorization computed by CPTTRF (see UPLO).
B (input/output) REAL array, dimension (LDB,NRHS)
On entry, the right hand side matrix B. On exit, the solution
matrix X.
LDB (input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
Page 1
CPTTRS(3F) CPTTRS(3F)
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
CPTTRS(3F) CPTTRS(3F)
CPTTRS  solve a system of linear equations A * X = B with a Hermitian
positive definite tridiagonal matrix A using the factorization A =
U**H*D*U or A = L*D*L**H computed by CPTTRF
SUBROUTINE CPTTRS( UPLO, N, NRHS, D, E, B, LDB, INFO )
CHARACTER UPLO
INTEGER INFO, LDB, N, NRHS
REAL D( * )
COMPLEX B( LDB, * ), E( * )
CPTTRS solves a system of linear equations A * X = B with a Hermitian
positive definite tridiagonal matrix A using the factorization A =
U**H*D*U or A = L*D*L**H computed by CPTTRF.
UPLO (input) CHARACTER*1
Specifies whether the superdiagonal or the subdiagonal of the
tridiagonal matrix A is stored and the form of the factorization:
= 'U': E is the superdiagonal of U, and A = U'*D*U;
= 'L': E is the subdiagonal of L, and A = L*D*L'. (The two
forms are equivalent if A is real.)
N (input) INTEGER
The order of the tridiagonal matrix A. N >= 0.
NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns of
the matrix B. NRHS >= 0.
D (input) REAL array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
factorization computed by CPTTRF.
E (input) COMPLEX array, dimension (N1)
The (n1) offdiagonal elements of the unit bidiagonal factor U
or L from the factorization computed by CPTTRF (see UPLO).
B (input/output) REAL array, dimension (LDB,NRHS)
On entry, the right hand side matrix B. On exit, the solution
matrix X.
LDB (input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
Page 1
CPTTRS(3F) CPTTRS(3F)
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
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