101 SUBROUTINE spotrf ( UPLO, N, A, LDA, INFO )
120 parameter ( one = 1.0e+0 )
129 EXTERNAL lsame, ilaenv
142 upper = lsame( uplo,
'U' )
143 IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
145 ELSE IF( n.LT.0 )
THEN
147 ELSE IF( lda.LT.max( 1, n ) )
THEN
151 CALL xerbla(
'SPOTRF', -info )
162 nb = ilaenv( 1,
'SPOTRF', uplo, n, -1, -1, -1 )
163 IF( nb.LE.1 .OR. nb.GE.n )
THEN
167 CALL spotf2( uplo, n, a, lda, info )
178 jb = min( nb, n-j+1 )
182 CALL strsm(
'Left',
'Upper',
'Transpose',
'Non-unit',
183 $ j-1, jb, one, a( 1, 1 ), lda,
186 CALL ssyrk(
'Upper',
'Transpose', jb, j-1, -one,
188 $ one, a( j, j ), lda )
193 CALL spotf2(
'Upper', jb, a( j, j ), lda, info )
205 jb = min( nb, n-j+1 )
209 CALL strsm(
'Right',
'Lower',
'Transpose',
'Non-unit',
210 $ jb, j-1, one, a( 1, 1 ), lda,
213 CALL ssyrk(
'Lower',
'No Transpose', jb, j-1,
214 $ -one, a( j, 1 ), lda,
215 $ one, a( j, j ), lda )
220 CALL spotf2(
'Lower', jb, a( j, j ), lda, info )
subroutine ssyrk(UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C, LDC)
SSYRK
subroutine strsm(SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA, B, LDB)
STRSM
subroutine sgemm(TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
SGEMM
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine spotrf(UPLO, N, A, LDA, INFO)
SPOTRF
subroutine spotf2(UPLO, N, A, LDA, INFO)
SPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblock...