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