133 RECURSIVE SUBROUTINE zgeqrt3( M, N, A, LDA, T, LDT, INFO )
141 INTEGER INFO, LDA, M, N, LDT
144 COMPLEX*16 A( lda, * ), T( ldt, * )
151 parameter( one = (1.0d+00,0.0d+00) )
154 INTEGER I, I1, J, J1, N1, N2, IINFO
164 ELSE IF( m .LT. n )
THEN
166 ELSE IF( lda .LT. max( 1, m ) )
THEN
168 ELSE IF( ldt .LT. max( 1, n ) )
THEN
172 CALL xerbla(
'ZGEQRT3', -info )
180 CALL zlarfg( m, a(1,1), a( min( 2, m ), 1 ), 1, t(1,1) )
193 CALL zgeqrt3( m, n1, a, lda, t, ldt, iinfo )
199 t( i, j+n1 ) = a( i, j+n1 )
202 CALL ztrmm(
'L',
'L',
'C',
'U', n1, n2, one,
203 & a, lda, t( 1, j1 ), ldt )
205 CALL zgemm(
'C',
'N', n1, n2, m-n1, one, a( j1, 1 ), lda,
206 & a( j1, j1 ), lda, one, t( 1, j1 ), ldt)
208 CALL ztrmm(
'L',
'U',
'C',
'N', n1, n2, one,
209 & t, ldt, t( 1, j1 ), ldt )
211 CALL zgemm(
'N',
'N', m-n1, n2, n1, -one, a( j1, 1 ), lda,
212 & t( 1, j1 ), ldt, one, a( j1, j1 ), lda )
214 CALL ztrmm(
'L',
'L',
'N',
'U', n1, n2, one,
215 & a, lda, t( 1, j1 ), ldt )
219 a( i, j+n1 ) = a( i, j+n1 ) - t( i, j+n1 )
225 CALL zgeqrt3( m-n1, n2, a( j1, j1 ), lda,
226 & t( j1, j1 ), ldt, iinfo )
232 t( i, j+n1 ) = conjg(a( j+n1, i ))
236 CALL ztrmm(
'R',
'L',
'N',
'U', n1, n2, one,
237 & a( j1, j1 ), lda, t( 1, j1 ), ldt )
239 CALL zgemm(
'C',
'N', n1, n2, m-n, one, a( i1, 1 ), lda,
240 & a( i1, j1 ), lda, one, t( 1, j1 ), ldt )
242 CALL ztrmm(
'L',
'U',
'N',
'N', n1, n2, -one, t, ldt,
245 CALL ztrmm(
'R',
'U',
'N',
'N', n1, n2, one,
246 & t( j1, j1 ), ldt, t( 1, j1 ), ldt )
subroutine zgemm(TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
ZGEMM
recursive subroutine zgeqrt3(M, N, A, LDA, T, LDT, INFO)
ZGEQRT3 recursively computes a QR factorization of a general real or complex matrix using the compact...
subroutine ztrmm(SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA, B, LDB)
ZTRMM
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine zlarfg(N, ALPHA, X, INCX, TAU)
ZLARFG generates an elementary reflector (Householder matrix).