LAPACK  3.10.0
LAPACK: Linear Algebra PACKage

◆ cgrqts()

subroutine cgrqts ( integer  M,
integer  P,
integer  N,
complex, dimension( lda, * )  A,
complex, dimension( lda, * )  AF,
complex, dimension( lda, * )  Q,
complex, dimension( lda, * )  R,
integer  LDA,
complex, dimension( * )  TAUA,
complex, dimension( ldb, * )  B,
complex, dimension( ldb, * )  BF,
complex, dimension( ldb, * )  Z,
complex, dimension( ldb, * )  T,
complex, dimension( ldb, * )  BWK,
integer  LDB,
complex, dimension( * )  TAUB,
complex, dimension( lwork )  WORK,
integer  LWORK,
real, dimension( * )  RWORK,
real, dimension( 4 )  RESULT 
)

CGRQTS

Purpose:
 CGRQTS tests CGGRQF, which computes the GRQ factorization of an
 M-by-N matrix A and a P-by-N matrix B: A = R*Q and B = Z*T*Q.
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 COMPLEX array, dimension (LDA,N)
          The M-by-N matrix A.
[out]AF
          AF is COMPLEX array, dimension (LDA,N)
          Details of the GRQ factorization of A and B, as returned
          by CGGRQF, see CGGRQF for further details.
[out]Q
          Q is COMPLEX array, dimension (LDA,N)
          The N-by-N unitary matrix Q.
[out]R
          R is COMPLEX array, dimension (LDA,MAX(M,N))
[in]LDA
          LDA is INTEGER
          The leading dimension of the arrays A, AF, R and Q.
          LDA >= max(M,N).
[out]TAUA
          TAUA is COMPLEX array, dimension (min(M,N))
          The scalar factors of the elementary reflectors, as returned
          by SGGQRC.
[in]B
          B is COMPLEX array, dimension (LDB,N)
          On entry, the P-by-N matrix A.
[out]BF
          BF is COMPLEX array, dimension (LDB,N)
          Details of the GQR factorization of A and B, as returned
          by CGGRQF, see CGGRQF for further details.
[out]Z
          Z is REAL array, dimension (LDB,P)
          The P-by-P unitary matrix Z.
[out]T
          T is COMPLEX array, dimension (LDB,max(P,N))
[out]BWK
          BWK is COMPLEX array, dimension (LDB,N)
[in]LDB
          LDB is INTEGER
          The leading dimension of the arrays B, BF, Z and T.
          LDB >= max(P,N).
[out]TAUB
          TAUB is COMPLEX array, dimension (min(P,N))
          The scalar factors of the elementary reflectors, as returned
          by SGGRQF.
[out]WORK
          WORK is COMPLEX array, dimension (LWORK)
[in]LWORK
          LWORK is INTEGER
          The dimension of the array WORK, LWORK >= max(M,P,N)**2.
[out]RWORK
          RWORK is REAL array, dimension (M)
[out]RESULT
          RESULT is REAL array, dimension (4)
          The test ratios:
            RESULT(1) = norm( R - A*Q' ) / ( MAX(M,N)*norm(A)*ULP)
            RESULT(2) = norm( T*Q - Z'*B ) / (MAX(P,N)*norm(B)*ULP)
            RESULT(3) = norm( I - Q'*Q ) / ( N*ULP )
            RESULT(4) = norm( I - Z'*Z ) / ( P*ULP )
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.

Definition at line 174 of file cgrqts.f.

176 *
177 * -- LAPACK test routine --
178 * -- LAPACK is a software package provided by Univ. of Tennessee, --
179 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
180 *
181 * .. Scalar Arguments ..
182  INTEGER LDA, LDB, LWORK, M, P, N
183 * ..
184 * .. Array Arguments ..
185  REAL RESULT( 4 ), RWORK( * )
186  COMPLEX A( LDA, * ), AF( LDA, * ), R( LDA, * ),
187  $ Q( LDA, * ), B( LDB, * ), BF( LDB, * ),
188  $ T( LDB, * ), Z( LDB, * ), BWK( LDB, * ),
189  $ TAUA( * ), TAUB( * ), WORK( LWORK )
190 * ..
191 *
192 * =====================================================================
193 *
194 * .. Parameters ..
195  REAL ZERO, ONE
196  parameter( zero = 0.0e+0, one = 1.0e+0 )
197  COMPLEX CZERO, CONE
198  parameter( czero = ( 0.0e+0, 0.0e+0 ),
199  $ cone = ( 1.0e+0, 0.0e+0 ) )
200  COMPLEX CROGUE
201  parameter( crogue = ( -1.0e+10, 0.0e+0 ) )
202 * ..
203 * .. Local Scalars ..
204  INTEGER INFO
205  REAL ANORM, BNORM, ULP, UNFL, RESID
206 * ..
207 * .. External Functions ..
208  REAL SLAMCH, CLANGE, CLANHE
209  EXTERNAL slamch, clange, clanhe
210 * ..
211 * .. External Subroutines ..
212  EXTERNAL cgemm, cggrqf, clacpy, claset, cungqr,
213  $ cungrq, cherk
214 * ..
215 * .. Intrinsic Functions ..
216  INTRINSIC max, min, real
217 * ..
218 * .. Executable Statements ..
219 *
220  ulp = slamch( 'Precision' )
221  unfl = slamch( 'Safe minimum' )
222 *
223 * Copy the matrix A to the array AF.
224 *
225  CALL clacpy( 'Full', m, n, a, lda, af, lda )
226  CALL clacpy( 'Full', p, n, b, ldb, bf, ldb )
227 *
228  anorm = max( clange( '1', m, n, a, lda, rwork ), unfl )
229  bnorm = max( clange( '1', p, n, b, ldb, rwork ), unfl )
230 *
231 * Factorize the matrices A and B in the arrays AF and BF.
232 *
233  CALL cggrqf( m, p, n, af, lda, taua, bf, ldb, taub, work,
234  $ lwork, info )
235 *
236 * Generate the N-by-N matrix Q
237 *
238  CALL claset( 'Full', n, n, crogue, crogue, q, lda )
239  IF( m.LE.n ) THEN
240  IF( m.GT.0 .AND. m.LT.n )
241  $ CALL clacpy( 'Full', m, n-m, af, lda, q( n-m+1, 1 ), lda )
242  IF( m.GT.1 )
243  $ CALL clacpy( 'Lower', m-1, m-1, af( 2, n-m+1 ), lda,
244  $ q( n-m+2, n-m+1 ), lda )
245  ELSE
246  IF( n.GT.1 )
247  $ CALL clacpy( 'Lower', n-1, n-1, af( m-n+2, 1 ), lda,
248  $ q( 2, 1 ), lda )
249  END IF
250  CALL cungrq( n, n, min( m, n ), q, lda, taua, work, lwork, info )
251 *
252 * Generate the P-by-P matrix Z
253 *
254  CALL claset( 'Full', p, p, crogue, crogue, z, ldb )
255  IF( p.GT.1 )
256  $ CALL clacpy( 'Lower', p-1, n, bf( 2,1 ), ldb, z( 2,1 ), ldb )
257  CALL cungqr( p, p, min( p,n ), z, ldb, taub, work, lwork, info )
258 *
259 * Copy R
260 *
261  CALL claset( 'Full', m, n, czero, czero, r, lda )
262  IF( m.LE.n )THEN
263  CALL clacpy( 'Upper', m, m, af( 1, n-m+1 ), lda, r( 1, n-m+1 ),
264  $ lda )
265  ELSE
266  CALL clacpy( 'Full', m-n, n, af, lda, r, lda )
267  CALL clacpy( 'Upper', n, n, af( m-n+1, 1 ), lda, r( m-n+1, 1 ),
268  $ lda )
269  END IF
270 *
271 * Copy T
272 *
273  CALL claset( 'Full', p, n, czero, czero, t, ldb )
274  CALL clacpy( 'Upper', p, n, bf, ldb, t, ldb )
275 *
276 * Compute R - A*Q'
277 *
278  CALL cgemm( 'No transpose', 'Conjugate transpose', m, n, n, -cone,
279  $ a, lda, q, lda, cone, r, lda )
280 *
281 * Compute norm( R - A*Q' ) / ( MAX(M,N)*norm(A)*ULP ) .
282 *
283  resid = clange( '1', m, n, r, lda, rwork )
284  IF( anorm.GT.zero ) THEN
285  result( 1 ) = ( ( resid / real(max(1,m,n) ) ) / anorm ) / ulp
286  ELSE
287  result( 1 ) = zero
288  END IF
289 *
290 * Compute T*Q - Z'*B
291 *
292  CALL cgemm( 'Conjugate transpose', 'No transpose', p, n, p, cone,
293  $ z, ldb, b, ldb, czero, bwk, ldb )
294  CALL cgemm( 'No transpose', 'No transpose', p, n, n, cone, t, ldb,
295  $ q, lda, -cone, bwk, ldb )
296 *
297 * Compute norm( T*Q - Z'*B ) / ( MAX(P,N)*norm(A)*ULP ) .
298 *
299  resid = clange( '1', p, n, bwk, ldb, rwork )
300  IF( bnorm.GT.zero ) THEN
301  result( 2 ) = ( ( resid / real( max( 1,p,m ) ) )/bnorm ) / ulp
302  ELSE
303  result( 2 ) = zero
304  END IF
305 *
306 * Compute I - Q*Q'
307 *
308  CALL claset( 'Full', n, n, czero, cone, r, lda )
309  CALL cherk( 'Upper', 'No Transpose', n, n, -one, q, lda, one, r,
310  $ lda )
311 *
312 * Compute norm( I - Q'*Q ) / ( N * ULP ) .
313 *
314  resid = clanhe( '1', 'Upper', n, r, lda, rwork )
315  result( 3 ) = ( resid / real( max( 1,n ) ) ) / ulp
316 *
317 * Compute I - Z'*Z
318 *
319  CALL claset( 'Full', p, p, czero, cone, t, ldb )
320  CALL cherk( 'Upper', 'Conjugate transpose', p, p, -one, z, ldb,
321  $ one, t, ldb )
322 *
323 * Compute norm( I - Z'*Z ) / ( P*ULP ) .
324 *
325  resid = clanhe( '1', 'Upper', p, t, ldb, rwork )
326  result( 4 ) = ( resid / real( max( 1,p ) ) ) / ulp
327 *
328  RETURN
329 *
330 * End of CGRQTS
331 *
subroutine cgemm(TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
CGEMM
Definition: cgemm.f:187
subroutine cherk(UPLO, TRANS, N, K, ALPHA, A, LDA, BETA, C, LDC)
CHERK
Definition: cherk.f:173
real function clange(NORM, M, N, A, LDA, WORK)
CLANGE returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value ...
Definition: clange.f:115
real function clanhe(NORM, UPLO, N, A, LDA, WORK)
CLANHE returns the value of the 1-norm, or the Frobenius norm, or the infinity norm,...
Definition: clanhe.f:124
subroutine claset(UPLO, M, N, ALPHA, BETA, A, LDA)
CLASET initializes the off-diagonal elements and the diagonal elements of a matrix to given values.
Definition: claset.f:106
subroutine clacpy(UPLO, M, N, A, LDA, B, LDB)
CLACPY copies all or part of one two-dimensional array to another.
Definition: clacpy.f:103
subroutine cggrqf(M, P, N, A, LDA, TAUA, B, LDB, TAUB, WORK, LWORK, INFO)
CGGRQF
Definition: cggrqf.f:214
subroutine cungqr(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
CUNGQR
Definition: cungqr.f:128
subroutine cungrq(M, N, K, A, LDA, TAU, WORK, LWORK, INFO)
CUNGRQ
Definition: cungrq.f:128
real function slamch(CMACH)
SLAMCH
Definition: slamch.f:68
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