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
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
integer function ilaenv(ISPEC, NAME, OPTS, N1, N2, N3, N4)
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.