101 SUBROUTINE spotrf ( UPLO, N, A, LDA, INFO )
120 parameter( one = 1.0e+0 )
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 )