spbtrs(3P) Sun Performance Library spbtrs(3P)NAMEspbtrs - solve a system of linear equations A*X = B with a symmetric
positive definite band matrix A using the Cholesky factorization A =
U**T*U or A = L*L**T computed by SPBTRF
SYNOPSIS
SUBROUTINE SPBTRS(UPLO, N, KD, NRHS, A, LDA, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER N, KD, NRHS, LDA, LDB, INFO
REAL A(LDA,*), B(LDB,*)
SUBROUTINE SPBTRS_64(UPLO, N, KD, NRHS, A, LDA, B, LDB, INFO)
CHARACTER * 1 UPLO
INTEGER*8 N, KD, NRHS, LDA, LDB, INFO
REAL A(LDA,*), B(LDB,*)
F95 INTERFACE
SUBROUTINE PBTRS(UPLO, [N], KD, [NRHS], A, [LDA], B, [LDB], [INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER :: N, KD, NRHS, LDA, LDB, INFO
REAL, DIMENSION(:,:) :: A, B
SUBROUTINE PBTRS_64(UPLO, [N], KD, [NRHS], A, [LDA], B, [LDB],
[INFO])
CHARACTER(LEN=1) :: UPLO
INTEGER(8) :: N, KD, NRHS, LDA, LDB, INFO
REAL, DIMENSION(:,:) :: A, B
C INTERFACE
#include <sunperf.h>
void spbtrs(char uplo, int n, int kd, int nrhs, float *a, int lda,
float *b, int ldb, int *info);
void spbtrs_64(char uplo, long n, long kd, long nrhs, float *a, long
lda, float *b, long ldb, long *info);
PURPOSEspbtrs solves a system of linear equations A*X = B with a symmetric
positive definite band matrix A using the Cholesky factorization A =
U**T*U or A = L*L**T computed by SPBTRF.
ARGUMENTS
UPLO (input)
= 'U': Upper triangular factor stored in A;
= 'L': Lower triangular factor stored in A.
N (input) The order of the matrix A. N >= 0.
KD (input)
The number of superdiagonals of the matrix A if UPLO = 'U',
or the number of subdiagonals if UPLO = 'L'. KD >= 0.
NRHS (input)
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0.
A (input) The triangular factor U or L from the Cholesky factorization
A = U**T*U or A = L*L**T of the band matrix A, stored in the
first KD+1 rows of the array. The j-th column of U or L is
stored in the j-th column of the array A as follows: if UPLO
='U', A(kd+1+i-j,j) = U(i,j) for max(1,j-kd)<=i<=j; if UPLO
='L', A(1+i-j,j) = L(i,j) for j<=i<=min(n,j+kd).
LDA (input)
The leading dimension of the array A. LDA >= KD+1.
B (input/output)
On entry, the right hand side matrix B. On exit, the solu‐
tion matrix X.
LDB (input)
The leading dimension of the array B. LDB >= max(1,N).
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
6 Mar 2009 spbtrs(3P)
