CGBTRS(l) ) CGBTRS(l)
CGBTRS - solve a system of linear equations A * X = B, A**T * X = B, or A**H * X = B with
a general band matrix A using the LU factorization computed by CGBTRF
SUBROUTINE CGBTRS( TRANS, N, KL, KU, NRHS, AB, LDAB, IPIV, B, LDB, INFO )
INTEGER INFO, KL, KU, LDAB, LDB, N, NRHS
INTEGER IPIV( * )
COMPLEX AB( LDAB, * ), B( LDB, * )
CGBTRS solves a system of linear equations A * X = B, A**T * X = B, or A**H * X = B with a
general band matrix A using the LU factorization computed by CGBTRF.
TRANS (input) CHARACTER*1
Specifies the form of the system of equations. = 'N': A * X = B (No trans-
= 'T': A**T * X = B (Transpose)
= 'C': A**H * X = B (Conjugate transpose)
N (input) INTEGER
The order of the matrix A. N >= 0.
KL (input) INTEGER
The number of subdiagonals within the band of A. KL >= 0.
KU (input) INTEGER
The number of superdiagonals within the band of A. KU >= 0.
NRHS (input) INTEGER
The number of right hand sides, i.e., the number of columns of the matrix B. NRHS
AB (input) COMPLEX array, dimension (LDAB,N)
Details of the LU factorization of the band matrix A, as computed by CGBTRF. U is
stored as an upper triangular band matrix with KL+KU superdiagonals in rows 1 to
KL+KU+1, and the multipliers used during the factorization are stored in rows
KL+KU+2 to 2*KL+KU+1.
LDAB (input) INTEGER
The leading dimension of the array AB. LDAB >= 2*KL+KU+1.
IPIV (input) INTEGER array, dimension (N)
The pivot indices; for 1 <= i <= N, row i of the matrix was interchanged with row
B (input/output) COMPLEX 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).
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
LAPACK version 3.0 15 June 2000 CGBTRS(l)