101 SUBROUTINE sgetrf ( M, N, A, LDA, IPIV, INFO)
109 INTEGER info, lda, m, n
120 parameter( one = 1.0e+0 )
123 INTEGER i, iinfo,
j, jb, k, nb
142 ELSE IF( n.LT.0 )
THEN
144 ELSE IF( lda.LT.max( 1, m ) )
THEN
148 CALL
xerbla(
'SGETRF', -info )
154 IF( m.EQ.0 .OR. n.EQ.0 )
159 nb =
ilaenv( 1,
'SGETRF',
' ', m, n, -1, -1 )
160 IF( nb.LE.1 .OR. nb.GE.min( m, n ) )
THEN
164 CALL
sgetf2( m, n, a, lda, ipiv, info )
170 DO 20
j = 1, min( m, n ), nb
171 jb = min( min( m, n )-
j+1, nb )
176 DO 30 k = 1,
j-nb, nb
180 CALL
slaswp( jb, a(1,
j), lda, k, k+nb-1, ipiv, 1 )
184 CALL
strsm(
'Left',
'Lower',
'No transpose',
'Unit',
185 $ nb, jb, one, a( k, k ), lda,
190 CALL
sgemm(
'No transpose',
'No transpose',
191 $ m-k-nb+1, jb, nb, -one,
192 $ a( k+nb, k ), lda, a( k,
j ), lda, one,
193 $ a( k+nb,
j ), lda )
199 CALL
sgetf2( m-
j+1, jb, a(
j,
j ), lda, ipiv(
j ), iinfo )
203 IF( info.EQ.0 .AND. iinfo.GT.0 )
204 $ info = iinfo +
j - 1
205 DO 10 i =
j, min( m,
j+jb-1 )
206 ipiv( i ) =
j - 1 + ipiv( i )
214 DO 40 k = 1, min( m, n ), nb
215 CALL
slaswp( k-1, a( 1, 1 ), lda, k,
216 $ min(k+nb-1, min( m, n )), ipiv, 1 )
223 CALL
slaswp( n-m, a(1, m+1), lda, 1, m, ipiv, 1 )
227 jb = min( m-k+1, nb )
229 CALL
strsm(
'Left',
'Lower',
'No transpose',
'Unit',
230 $ jb, n-m, one, a( k, k ), lda,
234 IF ( k+nb.LE.m )
THEN
235 CALL
sgemm(
'No transpose',
'No transpose',
236 $ m-k-nb+1, n-m, nb, -one,
237 $ a( k+nb, k ), lda, a( k, m+1 ), lda, one,
238 $ a( k+nb, m+1 ), lda )
subroutine sgetrf(M, N, A, LDA, IPIV, INFO)
SGETRF
subroutine xerbla(SRNAME, INFO)
XERBLA
INTEGER function ilaenv(ISPEC, NAME, OPTS, N1, N2, N3, N4)
subroutine sgemm(TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
SGEMM
set ue cd $ADTTMP cat<< EOF > tmp f Program LinearEquations Implicit none Real j
subroutine sgetf2(M, N, A, LDA, IPIV, INFO)
SGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row inter...
subroutine strsm(SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA, B, LDB)
STRSM
subroutine slaswp(N, A, LDA, K1, K2, IPIV, INCX)
SLASWP performs a series of row interchanges on a general rectangular matrix.