170 SUBROUTINE slahrd( N, K, NB, A, LDA, TAU, T, LDT, Y, LDY )
178 INTEGER K, LDA, LDT, LDY, N, NB
181 REAL A( lda, * ), T( ldt, nb ), TAU( nb ),
189 parameter( zero = 0.0e+0, one = 1.0e+0 )
215 CALL sgemv(
'No transpose', n, i-1, -one, y, ldy,
216 $ a( k+i-1, 1 ), lda, one, a( 1, i ), 1 )
228 CALL scopy( i-1, a( k+1, i ), 1, t( 1, nb ), 1 )
229 CALL strmv(
'Lower',
'Transpose',
'Unit', i-1, a( k+1, 1 ),
230 $ lda, t( 1, nb ), 1 )
234 CALL sgemv(
'Transpose', n-k-i+1, i-1, one, a( k+i, 1 ),
235 $ lda, a( k+i, i ), 1, one, t( 1, nb ), 1 )
239 CALL strmv(
'Upper',
'Transpose',
'Non-unit', i-1, t, ldt,
244 CALL sgemv(
'No transpose', n-k-i+1, i-1, -one, a( k+i, 1 ),
245 $ lda, t( 1, nb ), 1, one, a( k+i, i ), 1 )
249 CALL strmv(
'Lower',
'No transpose',
'Unit', i-1,
250 $ a( k+1, 1 ), lda, t( 1, nb ), 1 )
251 CALL saxpy( i-1, -one, t( 1, nb ), 1, a( k+1, i ), 1 )
259 CALL slarfg( n-k-i+1, a( k+i, i ), a( min( k+i+1, n ), i ), 1,
266 CALL sgemv(
'No transpose', n, n-k-i+1, one, a( 1, i+1 ), lda,
267 $ a( k+i, i ), 1, zero, y( 1, i ), 1 )
268 CALL sgemv(
'Transpose', n-k-i+1, i-1, one, a( k+i, 1 ), lda,
269 $ a( k+i, i ), 1, zero, t( 1, i ), 1 )
270 CALL sgemv(
'No transpose', n, i-1, -one, y, ldy, t( 1, i ), 1,
271 $ one, y( 1, i ), 1 )
272 CALL sscal( n, tau( i ), y( 1, i ), 1 )
276 CALL sscal( i-1, -tau( i ), t( 1, i ), 1 )
277 CALL strmv(
'Upper',
'No transpose',
'Non-unit', i-1, t, ldt,
subroutine strmv(UPLO, TRANS, DIAG, N, A, LDA, X, INCX)
STRMV
subroutine scopy(N, SX, INCX, SY, INCY)
SCOPY
subroutine saxpy(N, SA, SX, INCX, SY, INCY)
SAXPY
subroutine sgemv(TRANS, M, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY)
SGEMV
subroutine slarfg(N, ALPHA, X, INCX, TAU)
SLARFG generates an elementary reflector (Householder matrix).
subroutine slahrd(N, K, NB, A, LDA, TAU, T, LDT, Y, LDY)
SLAHRD reduces the first nb columns of a general rectangular matrix A so that elements below the k-th...
subroutine sscal(N, SA, SX, INCX)
SSCAL