99 DOUBLE PRECISION FUNCTION dqrt11( M, K, A, LDA, TAU, WORK, LWORK )
107 INTEGER K, LDA, LWORK, M
110 DOUBLE PRECISION A( lda, * ), TAU( * ), WORK( lwork )
116 DOUBLE PRECISION ZERO, ONE
117 parameter ( zero = 0.0d0, one = 1.0d0 )
123 DOUBLE PRECISION DLAMCH, DLANGE
124 EXTERNAL dlamch, dlange
133 DOUBLE PRECISION RDUMMY( 1 )
141 IF( lwork.LT.m*m+m )
THEN
142 CALL xerbla(
'DQRT11', 7 )
151 CALL dlaset(
'Full', m, m, zero, one, work, m )
155 CALL dorm2r(
'Left',
'No transpose', m, m, k, a, lda, tau, work,
156 $ m, work( m*m+1 ), info )
160 CALL dorm2r(
'Left',
'Transpose', m, m, k, a, lda, tau, work, m,
161 $ work( m*m+1 ), info )
164 work( ( j-1 )*m+j ) = work( ( j-1 )*m+j ) - one
167 dqrt11 = dlange(
'One-norm', m, m, work, m, rdummy ) /
168 $ ( dble( m )*dlamch(
'Epsilon' ) )
subroutine dlaset(UPLO, M, N, ALPHA, BETA, A, LDA)
DLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values...
double precision function dqrt11(M, K, A, LDA, TAU, WORK, LWORK)
DQRT11
subroutine dorm2r(SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, INFO)
DORM2R multiplies a general matrix by the orthogonal matrix from a QR factorization determined by sge...
subroutine xerbla(SRNAME, INFO)
XERBLA