LAPACK  3.8.0
LAPACK: Linear Algebra PACKage

◆ dgsvts3()

subroutine dgsvts3 ( integer  M,
integer  P,
integer  N,
double precision, dimension( lda, * )  A,
double precision, dimension( lda, * )  AF,
integer  LDA,
double precision, dimension( ldb, * )  B,
double precision, dimension( ldb, * )  BF,
integer  LDB,
double precision, dimension( ldu, * )  U,
integer  LDU,
double precision, dimension( ldv, * )  V,
integer  LDV,
double precision, dimension( ldq, * )  Q,
integer  LDQ,
double precision, dimension( * )  ALPHA,
double precision, dimension( * )  BETA,
double precision, dimension( ldr, * )  R,
integer  LDR,
integer, dimension( * )  IWORK,
double precision, dimension( lwork )  WORK,
integer  LWORK,
double precision, dimension( * )  RWORK,
double precision, dimension( 6 )  RESULT 
)

DGSVTS3

Purpose:
 DGSVTS3 tests DGGSVD3, which computes the GSVD of an M-by-N matrix A
 and a P-by-N matrix B:
              U'*A*Q = D1*R and V'*B*Q = D2*R.
Parameters
[in]M
          M is INTEGER
          The number of rows of the matrix A.  M >= 0.
[in]P
          P is INTEGER
          The number of rows of the matrix B.  P >= 0.
[in]N
          N is INTEGER
          The number of columns of the matrices A and B.  N >= 0.
[in]A
          A is DOUBLE PRECISION array, dimension (LDA,M)
          The M-by-N matrix A.
[out]AF
          AF is DOUBLE PRECISION array, dimension (LDA,N)
          Details of the GSVD of A and B, as returned by DGGSVD3,
          see DGGSVD3 for further details.
[in]LDA
          LDA is INTEGER
          The leading dimension of the arrays A and AF.
          LDA >= max( 1,M ).
[in]B
          B is DOUBLE PRECISION array, dimension (LDB,P)
          On entry, the P-by-N matrix B.
[out]BF
          BF is DOUBLE PRECISION array, dimension (LDB,N)
          Details of the GSVD of A and B, as returned by DGGSVD3,
          see DGGSVD3 for further details.
[in]LDB
          LDB is INTEGER
          The leading dimension of the arrays B and BF.
          LDB >= max(1,P).
[out]U
          U is DOUBLE PRECISION array, dimension(LDU,M)
          The M by M orthogonal matrix U.
[in]LDU
          LDU is INTEGER
          The leading dimension of the array U. LDU >= max(1,M).
[out]V
          V is DOUBLE PRECISION array, dimension(LDV,M)
          The P by P orthogonal matrix V.
[in]LDV
          LDV is INTEGER
          The leading dimension of the array V. LDV >= max(1,P).
[out]Q
          Q is DOUBLE PRECISION array, dimension(LDQ,N)
          The N by N orthogonal matrix Q.
[in]LDQ
          LDQ is INTEGER
          The leading dimension of the array Q. LDQ >= max(1,N).
[out]ALPHA
          ALPHA is DOUBLE PRECISION array, dimension (N)
[out]BETA
          BETA is DOUBLE PRECISION array, dimension (N)

          The generalized singular value pairs of A and B, the
          ``diagonal'' matrices D1 and D2 are constructed from
          ALPHA and BETA, see subroutine DGGSVD3 for details.
[out]R
          R is DOUBLE PRECISION array, dimension(LDQ,N)
          The upper triangular matrix R.
[in]LDR
          LDR is INTEGER
          The leading dimension of the array R. LDR >= max(1,N).
[out]IWORK
          IWORK is INTEGER array, dimension (N)
[out]WORK
          WORK is DOUBLE PRECISION array, dimension (LWORK)
[in]LWORK
          LWORK is INTEGER
          The dimension of the array WORK,
          LWORK >= max(M,P,N)*max(M,P,N).
[out]RWORK
          RWORK is DOUBLE PRECISION array, dimension (max(M,P,N))
[out]RESULT
          RESULT is DOUBLE PRECISION array, dimension (6)
          The test ratios:
          RESULT(1) = norm( U'*A*Q - D1*R ) / ( MAX(M,N)*norm(A)*ULP)
          RESULT(2) = norm( V'*B*Q - D2*R ) / ( MAX(P,N)*norm(B)*ULP)
          RESULT(3) = norm( I - U'*U ) / ( M*ULP )
          RESULT(4) = norm( I - V'*V ) / ( P*ULP )
          RESULT(5) = norm( I - Q'*Q ) / ( N*ULP )
          RESULT(6) = 0        if ALPHA is in decreasing order;
                    = ULPINV   otherwise.
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date
August 2015

Definition at line 212 of file dgsvts3.f.

212 *
213 * -- LAPACK test routine (version 3.7.0) --
214 * -- LAPACK is a software package provided by Univ. of Tennessee, --
215 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
216 * August 2015
217 *
218 * .. Scalar Arguments ..
219  INTEGER lda, ldb, ldq, ldr, ldu, ldv, lwork, m, n, p
220 * ..
221 * .. Array Arguments ..
222  INTEGER iwork( * )
223  DOUBLE PRECISION a( lda, * ), af( lda, * ), alpha( * ),
224  $ b( ldb, * ), beta( * ), bf( ldb, * ),
225  $ q( ldq, * ), r( ldr, * ), result( 6 ),
226  $ rwork( * ), u( ldu, * ), v( ldv, * ),
227  $ work( lwork )
228 * ..
229 *
230 * =====================================================================
231 *
232 * .. Parameters ..
233  DOUBLE PRECISION zero, one
234  parameter( zero = 0.0d+0, one = 1.0d+0 )
235 * ..
236 * .. Local Scalars ..
237  INTEGER i, info, j, k, l
238  DOUBLE PRECISION anorm, bnorm, resid, temp, ulp, ulpinv, unfl
239 * ..
240 * .. External Functions ..
241  DOUBLE PRECISION dlamch, dlange, dlansy
242  EXTERNAL dlamch, dlange, dlansy
243 * ..
244 * .. External Subroutines ..
245  EXTERNAL dcopy, dgemm, dggsvd3, dlacpy, dlaset, dsyrk
246 * ..
247 * .. Intrinsic Functions ..
248  INTRINSIC dble, max, min
249 * ..
250 * .. Executable Statements ..
251 *
252  ulp = dlamch( 'Precision' )
253  ulpinv = one / ulp
254  unfl = dlamch( 'Safe minimum' )
255 *
256 * Copy the matrix A to the array AF.
257 *
258  CALL dlacpy( 'Full', m, n, a, lda, af, lda )
259  CALL dlacpy( 'Full', p, n, b, ldb, bf, ldb )
260 *
261  anorm = max( dlange( '1', m, n, a, lda, rwork ), unfl )
262  bnorm = max( dlange( '1', p, n, b, ldb, rwork ), unfl )
263 *
264 * Factorize the matrices A and B in the arrays AF and BF.
265 *
266  CALL dggsvd3( 'U', 'V', 'Q', m, n, p, k, l, af, lda, bf, ldb,
267  $ alpha, beta, u, ldu, v, ldv, q, ldq, work, lwork,
268  $ iwork, info )
269 *
270 * Copy R
271 *
272  DO 20 i = 1, min( k+l, m )
273  DO 10 j = i, k + l
274  r( i, j ) = af( i, n-k-l+j )
275  10 CONTINUE
276  20 CONTINUE
277 *
278  IF( m-k-l.LT.0 ) THEN
279  DO 40 i = m + 1, k + l
280  DO 30 j = i, k + l
281  r( i, j ) = bf( i-k, n-k-l+j )
282  30 CONTINUE
283  40 CONTINUE
284  END IF
285 *
286 * Compute A:= U'*A*Q - D1*R
287 *
288  CALL dgemm( 'No transpose', 'No transpose', m, n, n, one, a, lda,
289  $ q, ldq, zero, work, lda )
290 *
291  CALL dgemm( 'Transpose', 'No transpose', m, n, m, one, u, ldu,
292  $ work, lda, zero, a, lda )
293 *
294  DO 60 i = 1, k
295  DO 50 j = i, k + l
296  a( i, n-k-l+j ) = a( i, n-k-l+j ) - r( i, j )
297  50 CONTINUE
298  60 CONTINUE
299 *
300  DO 80 i = k + 1, min( k+l, m )
301  DO 70 j = i, k + l
302  a( i, n-k-l+j ) = a( i, n-k-l+j ) - alpha( i )*r( i, j )
303  70 CONTINUE
304  80 CONTINUE
305 *
306 * Compute norm( U'*A*Q - D1*R ) / ( MAX(1,M,N)*norm(A)*ULP ) .
307 *
308  resid = dlange( '1', m, n, a, lda, rwork )
309 *
310  IF( anorm.GT.zero ) THEN
311  result( 1 ) = ( ( resid / dble( max( 1, m, n ) ) ) / anorm ) /
312  $ ulp
313  ELSE
314  result( 1 ) = zero
315  END IF
316 *
317 * Compute B := V'*B*Q - D2*R
318 *
319  CALL dgemm( 'No transpose', 'No transpose', p, n, n, one, b, ldb,
320  $ q, ldq, zero, work, ldb )
321 *
322  CALL dgemm( 'Transpose', 'No transpose', p, n, p, one, v, ldv,
323  $ work, ldb, zero, b, ldb )
324 *
325  DO 100 i = 1, l
326  DO 90 j = i, l
327  b( i, n-l+j ) = b( i, n-l+j ) - beta( k+i )*r( k+i, k+j )
328  90 CONTINUE
329  100 CONTINUE
330 *
331 * Compute norm( V'*B*Q - D2*R ) / ( MAX(P,N)*norm(B)*ULP ) .
332 *
333  resid = dlange( '1', p, n, b, ldb, rwork )
334  IF( bnorm.GT.zero ) THEN
335  result( 2 ) = ( ( resid / dble( max( 1, p, n ) ) ) / bnorm ) /
336  $ ulp
337  ELSE
338  result( 2 ) = zero
339  END IF
340 *
341 * Compute I - U'*U
342 *
343  CALL dlaset( 'Full', m, m, zero, one, work, ldq )
344  CALL dsyrk( 'Upper', 'Transpose', m, m, -one, u, ldu, one, work,
345  $ ldu )
346 *
347 * Compute norm( I - U'*U ) / ( M * ULP ) .
348 *
349  resid = dlansy( '1', 'Upper', m, work, ldu, rwork )
350  result( 3 ) = ( resid / dble( max( 1, m ) ) ) / ulp
351 *
352 * Compute I - V'*V
353 *
354  CALL dlaset( 'Full', p, p, zero, one, work, ldv )
355  CALL dsyrk( 'Upper', 'Transpose', p, p, -one, v, ldv, one, work,
356  $ ldv )
357 *
358 * Compute norm( I - V'*V ) / ( P * ULP ) .
359 *
360  resid = dlansy( '1', 'Upper', p, work, ldv, rwork )
361  result( 4 ) = ( resid / dble( max( 1, p ) ) ) / ulp
362 *
363 * Compute I - Q'*Q
364 *
365  CALL dlaset( 'Full', n, n, zero, one, work, ldq )
366  CALL dsyrk( 'Upper', 'Transpose', n, n, -one, q, ldq, one, work,
367  $ ldq )
368 *
369 * Compute norm( I - Q'*Q ) / ( N * ULP ) .
370 *
371  resid = dlansy( '1', 'Upper', n, work, ldq, rwork )
372  result( 5 ) = ( resid / dble( max( 1, n ) ) ) / ulp
373 *
374 * Check sorting
375 *
376  CALL dcopy( n, alpha, 1, work, 1 )
377  DO 110 i = k + 1, min( k+l, m )
378  j = iwork( i )
379  IF( i.NE.j ) THEN
380  temp = work( i )
381  work( i ) = work( j )
382  work( j ) = temp
383  END IF
384  110 CONTINUE
385 *
386  result( 6 ) = zero
387  DO 120 i = k + 1, min( k+l, m ) - 1
388  IF( work( i ).LT.work( i+1 ) )
389  $ result( 6 ) = ulpinv
390  120 CONTINUE
391 *
392  RETURN
393 *
394 * End of DGSVTS3
395 *
subroutine dlacpy(UPLO, M, N, A, LDA, B, LDB)
DLACPY copies all or part of one two-dimensional array to another.
Definition: dlacpy.f:105
double precision function dlamch(CMACH)
DLAMCH
Definition: dlamch.f:65
double precision function dlansy(NORM, UPLO, N, A, LDA, WORK)
DLANSY returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real symmetric matrix.
Definition: dlansy.f:124
subroutine dcopy(N, DX, INCX, DY, INCY)
DCOPY
Definition: dcopy.f:84
subroutine dggsvd3(JOBU, JOBV, JOBQ, M, N, P, K, L, A, LDA, B, LDB, ALPHA, BETA, U, LDU, V, LDV, Q, LDQ, WORK, LWORK, IWORK, INFO)
DGGSVD3 computes the singular value decomposition (SVD) for OTHER matrices
Definition: dggsvd3.f:351
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...
Definition: dlaset.f:112
subroutine dgemm(TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
DGEMM
Definition: dgemm.f:189
subroutine dsyrk(UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C, LDC)
DSYRK
Definition: dsyrk.f:171
double precision function dlange(NORM, M, N, A, LDA, WORK)
DLANGE returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value ...
Definition: dlange.f:116
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