LAPACK  3.10.1 LAPACK: Linear Algebra PACKage
cqrt15.f
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1 *> \brief \b CQRT15
2 *
3 * =========== DOCUMENTATION ===========
4 *
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
7 *
8 * Definition:
9 * ===========
10 *
11 * SUBROUTINE CQRT15( SCALE, RKSEL, M, N, NRHS, A, LDA, B, LDB, S,
12 * RANK, NORMA, NORMB, ISEED, WORK, LWORK )
13 *
14 * .. Scalar Arguments ..
15 * INTEGER LDA, LDB, LWORK, M, N, NRHS, RANK, RKSEL, SCALE
16 * REAL NORMA, NORMB
17 * ..
18 * .. Array Arguments ..
19 * INTEGER ISEED( 4 )
20 * REAL S( * )
21 * COMPLEX A( LDA, * ), B( LDB, * ), WORK( LWORK )
22 * ..
23 *
24 *
25 *> \par Purpose:
26 * =============
27 *>
28 *> \verbatim
29 *>
30 *> CQRT15 generates a matrix with full or deficient rank and of various
31 *> norms.
32 *> \endverbatim
33 *
34 * Arguments:
35 * ==========
36 *
37 *> \param[in] SCALE
38 *> \verbatim
39 *> SCALE is INTEGER
40 *> SCALE = 1: normally scaled matrix
41 *> SCALE = 2: matrix scaled up
42 *> SCALE = 3: matrix scaled down
43 *> \endverbatim
44 *>
45 *> \param[in] RKSEL
46 *> \verbatim
47 *> RKSEL is INTEGER
48 *> RKSEL = 1: full rank matrix
49 *> RKSEL = 2: rank-deficient matrix
50 *> \endverbatim
51 *>
52 *> \param[in] M
53 *> \verbatim
54 *> M is INTEGER
55 *> The number of rows of the matrix A.
56 *> \endverbatim
57 *>
58 *> \param[in] N
59 *> \verbatim
60 *> N is INTEGER
61 *> The number of columns of A.
62 *> \endverbatim
63 *>
64 *> \param[in] NRHS
65 *> \verbatim
66 *> NRHS is INTEGER
67 *> The number of columns of B.
68 *> \endverbatim
69 *>
70 *> \param[out] A
71 *> \verbatim
72 *> A is COMPLEX array, dimension (LDA,N)
73 *> The M-by-N matrix A.
74 *> \endverbatim
75 *>
76 *> \param[in] LDA
77 *> \verbatim
78 *> LDA is INTEGER
79 *> The leading dimension of the array A.
80 *> \endverbatim
81 *>
82 *> \param[out] B
83 *> \verbatim
84 *> B is COMPLEX array, dimension (LDB, NRHS)
85 *> A matrix that is in the range space of matrix A.
86 *> \endverbatim
87 *>
88 *> \param[in] LDB
89 *> \verbatim
90 *> LDB is INTEGER
91 *> The leading dimension of the array B.
92 *> \endverbatim
93 *>
94 *> \param[out] S
95 *> \verbatim
96 *> S is REAL array, dimension MIN(M,N)
97 *> Singular values of A.
98 *> \endverbatim
99 *>
100 *> \param[out] RANK
101 *> \verbatim
102 *> RANK is INTEGER
103 *> number of nonzero singular values of A.
104 *> \endverbatim
105 *>
106 *> \param[out] NORMA
107 *> \verbatim
108 *> NORMA is REAL
109 *> one-norm norm of A.
110 *> \endverbatim
111 *>
112 *> \param[out] NORMB
113 *> \verbatim
114 *> NORMB is REAL
115 *> one-norm norm of B.
116 *> \endverbatim
117 *>
118 *> \param[in,out] ISEED
119 *> \verbatim
120 *> ISEED is integer array, dimension (4)
121 *> seed for random number generator.
122 *> \endverbatim
123 *>
124 *> \param[out] WORK
125 *> \verbatim
126 *> WORK is COMPLEX array, dimension (LWORK)
127 *> \endverbatim
128 *>
129 *> \param[in] LWORK
130 *> \verbatim
131 *> LWORK is INTEGER
132 *> length of work space required.
133 *> LWORK >= MAX(M+MIN(M,N),NRHS*MIN(M,N),2*N+M)
134 *> \endverbatim
135 *
136 * Authors:
137 * ========
138 *
139 *> \author Univ. of Tennessee
140 *> \author Univ. of California Berkeley
141 *> \author Univ. of Colorado Denver
142 *> \author NAG Ltd.
143 *
144 *> \ingroup complex_lin
145 *
146 * =====================================================================
147  SUBROUTINE cqrt15( SCALE, RKSEL, M, N, NRHS, A, LDA, B, LDB, S,
148  \$ RANK, NORMA, NORMB, ISEED, WORK, LWORK )
149 *
150 * -- LAPACK test routine --
151 * -- LAPACK is a software package provided by Univ. of Tennessee, --
152 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
153 *
154 * .. Scalar Arguments ..
155  INTEGER LDA, LDB, LWORK, M, N, NRHS, RANK, RKSEL, SCALE
156  REAL NORMA, NORMB
157 * ..
158 * .. Array Arguments ..
159  INTEGER ISEED( 4 )
160  REAL S( * )
161  COMPLEX A( LDA, * ), B( LDB, * ), WORK( LWORK )
162 * ..
163 *
164 * =====================================================================
165 *
166 * .. Parameters ..
167  REAL ZERO, ONE, TWO, SVMIN
168  parameter( zero = 0.0e+0, one = 1.0e+0, two = 2.0e+0,
169  \$ svmin = 0.1e+0 )
170  COMPLEX CZERO, CONE
171  parameter( czero = ( 0.0e+0, 0.0e+0 ),
172  \$ cone = ( 1.0e+0, 0.0e+0 ) )
173 * ..
174 * .. Local Scalars ..
175  INTEGER INFO, J, MN
176  REAL BIGNUM, EPS, SMLNUM, TEMP
177 * ..
178 * .. Local Arrays ..
179  REAL DUMMY( 1 )
180 * ..
181 * .. External Functions ..
182  REAL CLANGE, SASUM, SCNRM2, SLAMCH, SLARND
183  EXTERNAL clange, sasum, scnrm2, slamch, slarnd
184 * ..
185 * .. External Subroutines ..
186  EXTERNAL cgemm, clarf, clarnv, claror, clascl, claset,
188 * ..
189 * .. Intrinsic Functions ..
190  INTRINSIC abs, cmplx, max, min
191 * ..
192 * .. Executable Statements ..
193 *
194  mn = min( m, n )
195  IF( lwork.LT.max( m+mn, mn*nrhs, 2*n+m ) ) THEN
196  CALL xerbla( 'CQRT15', 16 )
197  RETURN
198  END IF
199 *
200  smlnum = slamch( 'Safe minimum' )
201  bignum = one / smlnum
202  CALL slabad( smlnum, bignum )
203  eps = slamch( 'Epsilon' )
204  smlnum = ( smlnum / eps ) / eps
205  bignum = one / smlnum
206 *
207 * Determine rank and (unscaled) singular values
208 *
209  IF( rksel.EQ.1 ) THEN
210  rank = mn
211  ELSE IF( rksel.EQ.2 ) THEN
212  rank = ( 3*mn ) / 4
213  DO 10 j = rank + 1, mn
214  s( j ) = zero
215  10 CONTINUE
216  ELSE
217  CALL xerbla( 'CQRT15', 2 )
218  END IF
219 *
220  IF( rank.GT.0 ) THEN
221 *
222 * Nontrivial case
223 *
224  s( 1 ) = one
225  DO 30 j = 2, rank
226  20 CONTINUE
227  temp = slarnd( 1, iseed )
228  IF( temp.GT.svmin ) THEN
229  s( j ) = abs( temp )
230  ELSE
231  GO TO 20
232  END IF
233  30 CONTINUE
234  CALL slaord( 'Decreasing', rank, s, 1 )
235 *
236 * Generate 'rank' columns of a random orthogonal matrix in A
237 *
238  CALL clarnv( 2, iseed, m, work )
239  CALL csscal( m, one / scnrm2( m, work, 1 ), work, 1 )
240  CALL claset( 'Full', m, rank, czero, cone, a, lda )
241  CALL clarf( 'Left', m, rank, work, 1, cmplx( two ), a, lda,
242  \$ work( m+1 ) )
243 *
244 * workspace used: m+mn
245 *
246 * Generate consistent rhs in the range space of A
247 *
248  CALL clarnv( 2, iseed, rank*nrhs, work )
249  CALL cgemm( 'No transpose', 'No transpose', m, nrhs, rank,
250  \$ cone, a, lda, work, rank, czero, b, ldb )
251 *
252 * work space used: <= mn *nrhs
253 *
254 * generate (unscaled) matrix A
255 *
256  DO 40 j = 1, rank
257  CALL csscal( m, s( j ), a( 1, j ), 1 )
258  40 CONTINUE
259  IF( rank.LT.n )
260  \$ CALL claset( 'Full', m, n-rank, czero, czero,
261  \$ a( 1, rank+1 ), lda )
262  CALL claror( 'Right', 'No initialization', m, n, a, lda, iseed,
263  \$ work, info )
264 *
265  ELSE
266 *
267 * work space used 2*n+m
268 *
269 * Generate null matrix and rhs
270 *
271  DO 50 j = 1, mn
272  s( j ) = zero
273  50 CONTINUE
274  CALL claset( 'Full', m, n, czero, czero, a, lda )
275  CALL claset( 'Full', m, nrhs, czero, czero, b, ldb )
276 *
277  END IF
278 *
279 * Scale the matrix
280 *
281  IF( scale.NE.1 ) THEN
282  norma = clange( 'Max', m, n, a, lda, dummy )
283  IF( norma.NE.zero ) THEN
284  IF( scale.EQ.2 ) THEN
285 *
286 * matrix scaled up
287 *
288  CALL clascl( 'General', 0, 0, norma, bignum, m, n, a,
289  \$ lda, info )
290  CALL slascl( 'General', 0, 0, norma, bignum, mn, 1, s,
291  \$ mn, info )
292  CALL clascl( 'General', 0, 0, norma, bignum, m, nrhs, b,
293  \$ ldb, info )
294  ELSE IF( scale.EQ.3 ) THEN
295 *
296 * matrix scaled down
297 *
298  CALL clascl( 'General', 0, 0, norma, smlnum, m, n, a,
299  \$ lda, info )
300  CALL slascl( 'General', 0, 0, norma, smlnum, mn, 1, s,
301  \$ mn, info )
302  CALL clascl( 'General', 0, 0, norma, smlnum, m, nrhs, b,
303  \$ ldb, info )
304  ELSE
305  CALL xerbla( 'CQRT15', 1 )
306  RETURN
307  END IF
308  END IF
309  END IF
310 *
311  norma = sasum( mn, s, 1 )
312  normb = clange( 'One-norm', m, nrhs, b, ldb, dummy )
313 *
314  RETURN
315 *
316 * End of CQRT15
317 *
318  END
subroutine slascl(TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO)
SLASCL multiplies a general rectangular matrix by a real scalar defined as cto/cfrom.
Definition: slascl.f:143
subroutine xerbla(SRNAME, INFO)
XERBLA
Definition: xerbla.f:60
subroutine csscal(N, SA, CX, INCX)
CSSCAL
Definition: csscal.f:78
subroutine cgemm(TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, BETA, C, LDC)
CGEMM
Definition: cgemm.f:187
subroutine cqrt15(SCALE, RKSEL, M, N, NRHS, A, LDA, B, LDB, S, RANK, NORMA, NORMB, ISEED, WORK, LWORK)
CQRT15
Definition: cqrt15.f:149
subroutine claror(SIDE, INIT, M, N, A, LDA, ISEED, X, INFO)
CLAROR
Definition: claror.f:158
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 clarf(SIDE, M, N, V, INCV, TAU, C, LDC, WORK)
CLARF applies an elementary reflector to a general rectangular matrix.
Definition: clarf.f:128
subroutine clascl(TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO)
CLASCL multiplies a general rectangular matrix by a real scalar defined as cto/cfrom.
Definition: clascl.f:143
subroutine clarnv(IDIST, ISEED, N, X)
CLARNV returns a vector of random numbers from a uniform or normal distribution.
Definition: clarnv.f:99
subroutine slaord(JOB, N, X, INCX)
SLAORD
Definition: slaord.f:73