108 SUBROUTINE spotf2( UPLO, N, A, LDA, INFO )
126 parameter( one = 1.0e+0, zero = 0.0e+0 )
134 LOGICAL LSAME, SISNAN
136 EXTERNAL lsame, sdot, sisnan
149 upper = lsame( uplo,
'U' )
150 IF( .NOT.upper .AND. .NOT.lsame( uplo,
'L' ) )
THEN
152 ELSE IF( n.LT.0 )
THEN
154 ELSE IF( lda.LT.max( 1, n ) )
THEN
158 CALL xerbla(
'SPOTF2', -info )
175 ajj = a( j, j ) - sdot( j-1, a( 1, j ), 1, a( 1, j ), 1 )
176 IF( ajj.LE.zero.OR.sisnan( ajj ) )
THEN
186 CALL sgemv(
'Transpose', j-1, n-j, -one, a( 1, j+1 ),
187 $ lda, a( 1, j ), 1, one, a( j, j+1 ), lda )
188 CALL sscal( n-j, one / ajj, a( j, j+1 ), lda )
199 ajj = a( j, j ) - sdot( j-1, a( j, 1 ), lda, a( j, 1 ),
201 IF( ajj.LE.zero.OR.sisnan( ajj ) )
THEN
211 CALL sgemv(
'No transpose', n-j, j-1, -one, a( j+1, 1 ),
212 $ lda, a( j, 1 ), lda, one, a( j+1, j ), 1 )
213 CALL sscal( n-j, one / ajj, a( j+1, j ), 1 )
subroutine xerbla(srname, info)
subroutine sgemv(trans, m, n, alpha, a, lda, x, incx, beta, y, incy)
SGEMV
subroutine spotf2(uplo, n, a, lda, info)
SPOTF2 computes the Cholesky factorization of a symmetric/Hermitian positive definite matrix (unblock...
subroutine sscal(n, sa, sx, incx)
SSCAL