101 SUBROUTINE cgetrf ( M, N, A, LDA, IPIV, INFO)
109 INTEGER INFO, LDA, M, N
120 parameter ( one = (1.0e+0, 0.0e+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(
'CGETRF', -info )
154 IF( m.EQ.0 .OR. n.EQ.0 )
159 nb = ilaenv( 1,
'CGETRF',
' ', m, n, -1, -1 )
160 IF( nb.LE.1 .OR. nb.GE.min( m, n ) )
THEN
164 CALL cgetf2( 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 claswp( jb, a(1, j), lda, k, k+nb-1, ipiv, 1 )
184 CALL ctrsm(
'Left',
'Lower',
'No transpose',
'Unit',
185 $ nb, jb, one, a( k, k ), lda,
190 CALL cgemm(
'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 cgetf2( 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 claswp( k-1, a( 1, 1 ), lda, k,
216 $ min(k+nb-1, min( m, n )), ipiv, 1 )
223 CALL claswp( n-m, a(1, m+1), lda, 1, m, ipiv, 1 )
227 jb = min( m-k+1, nb )
229 CALL ctrsm(
'Left',
'Lower',
'No transpose',
'Unit',
230 $ jb, n-m, one, a( k, k ), lda,
234 IF ( k+nb.LE.m )
THEN
235 CALL cgemm(
'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 xerbla(SRNAME, INFO)
XERBLA
subroutine ctrsm(SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA, B, LDB)
CTRSM
subroutine cgetrf(M, N, A, LDA, IPIV, INFO)
CGETRF
subroutine cgetf2(M, N, A, LDA, IPIV, INFO)
CGETF2 computes the LU factorization of a general m-by-n matrix using partial pivoting with row inter...
subroutine cgemm(TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
CGEMM
subroutine claswp(N, A, LDA, K1, K2, IPIV, INCX)
CLASWP performs a series of row interchanges on a general rectangular matrix.