99 REAL FUNCTION sqrt11( M, K, A, LDA, TAU, WORK, LWORK )
107 INTEGER K, LDA, LWORK, M
110 REAL A( lda, * ), TAU( * ), WORK( lwork )
117 parameter ( zero = 0.0e0, one = 1.0e0 )
124 EXTERNAL slamch, slange
141 IF( lwork.LT.m*m+m )
THEN
142 CALL xerbla(
'SQRT11', 7 )
151 CALL slaset(
'Full', m, m, zero, one, work, m )
155 CALL sorm2r(
'Left',
'No transpose', m, m, k, a, lda, tau, work,
156 $ m, work( m*m+1 ), info )
160 CALL sorm2r(
'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 sqrt11 = slange(
'One-norm', m, m, work, m, rdummy ) /
168 $ (
REAL( m )*SLAMCH(
'Epsilon' ) )
subroutine sorm2r(SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, WORK, INFO)
SORM2R multiplies a general matrix by the orthogonal matrix from a QR factorization determined by sge...
real function sqrt11(M, K, A, LDA, TAU, WORK, LWORK)
SQRT11
subroutine xerbla(SRNAME, INFO)
XERBLA
subroutine slaset(UPLO, M, N, ALPHA, BETA, A, LDA)
SLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values...