143 SUBROUTINE spbtf2( UPLO, N, KD, AB, LDAB, INFO )
152 INTEGER INFO, KD, LDAB, N
162 parameter ( one = 1.0e+0, zero = 0.0e+0 )
177 INTRINSIC max, min, sqrt
184 upper = lsame( uplo,
'U' )
185 IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
187 ELSE IF( n.LT.0 )
THEN
189 ELSE IF( kd.LT.0 )
THEN
191 ELSE IF( ldab.LT.kd+1 )
THEN
195 CALL xerbla(
'SPBTF2', -info )
204 kld = max( 1, ldab-1 )
225 CALL sscal( kn, one / ajj, ab( kd, j+1 ), kld )
226 CALL ssyr(
'Upper', kn, -one, ab( kd, j+1 ), kld,
227 $ ab( kd+1, j+1 ), kld )
249 CALL sscal( kn, one / ajj, ab( 2, j ), 1 )
250 CALL ssyr(
'Lower', kn, -one, ab( 2, j ), 1,
251 $ ab( 1, j+1 ), kld )
subroutine spbtf2(UPLO, N, KD, AB, LDAB, INFO)
SPBTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite band matrix (un...
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine sscal(N, SA, SX, INCX)
SSCAL
subroutine ssyr(UPLO, N, ALPHA, X, INCX, A, LDA)
SSYR