LAPACK  3.8.0
LAPACK: Linear Algebra PACKage
ztrttp.f
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1 *> \brief \b ZTRTTP copies a triangular matrix from the standard full format (TR) to the standard packed format (TP).
2 *
3 * =========== DOCUMENTATION ===========
4 *
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
7 *
8 *> \htmlonly
9 *> Download ZTRTTP + dependencies
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11 *> [TGZ]</a>
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13 *> [ZIP]</a>
14 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ztrttp.f">
15 *> [TXT]</a>
16 *> \endhtmlonly
17 *
18 * Definition:
19 * ===========
20 *
21 * SUBROUTINE ZTRTTP( UPLO, N, A, LDA, AP, INFO )
22 *
23 * .. Scalar Arguments ..
24 * CHARACTER UPLO
25 * INTEGER INFO, N, LDA
26 * ..
27 * .. Array Arguments ..
28 * COMPLEX*16 A( LDA, * ), AP( * )
29 * ..
30 *
31 *
32 *> \par Purpose:
33 * =============
34 *>
35 *> \verbatim
36 *>
37 *> ZTRTTP copies a triangular matrix A from full format (TR) to standard
38 *> packed format (TP).
39 *> \endverbatim
40 *
41 * Arguments:
42 * ==========
43 *
44 *> \param[in] UPLO
45 *> \verbatim
46 *> UPLO is CHARACTER*1
47 *> = 'U': A is upper triangular;
48 *> = 'L': A is lower triangular.
49 *> \endverbatim
50 *>
51 *> \param[in] N
52 *> \verbatim
53 *> N is INTEGER
54 *> The order of the matrices AP and A. N >= 0.
55 *> \endverbatim
56 *>
57 *> \param[in] A
58 *> \verbatim
59 *> A is COMPLEX*16 array, dimension (LDA,N)
60 *> On entry, the triangular matrix A. If UPLO = 'U', the leading
61 *> N-by-N upper triangular part of A contains the upper
62 *> triangular part of the matrix A, and the strictly lower
63 *> triangular part of A is not referenced. If UPLO = 'L', the
64 *> leading N-by-N lower triangular part of A contains the lower
65 *> triangular part of the matrix A, and the strictly upper
66 *> triangular part of A is not referenced.
67 *> \endverbatim
68 *>
69 *> \param[in] LDA
70 *> \verbatim
71 *> LDA is INTEGER
72 *> The leading dimension of the array A. LDA >= max(1,N).
73 *> \endverbatim
74 *>
75 *> \param[out] AP
76 *> \verbatim
77 *> AP is COMPLEX*16 array, dimension ( N*(N+1)/2 ),
78 *> On exit, the upper or lower triangular matrix A, packed
79 *> columnwise in a linear array. The j-th column of A is stored
80 *> in the array AP as follows:
81 *> if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
82 *> if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
83 *> \endverbatim
84 *>
85 *> \param[out] INFO
86 *> \verbatim
87 *> INFO is INTEGER
88 *> = 0: successful exit
89 *> < 0: if INFO = -i, the i-th argument had an illegal value
90 *> \endverbatim
91 *
92 * Authors:
93 * ========
94 *
95 *> \author Univ. of Tennessee
96 *> \author Univ. of California Berkeley
97 *> \author Univ. of Colorado Denver
98 *> \author NAG Ltd.
99 *
100 *> \date December 2016
101 *
102 *> \ingroup complex16OTHERcomputational
103 *
104 * =====================================================================
105  SUBROUTINE ztrttp( UPLO, N, A, LDA, AP, INFO )
106 *
107 * -- LAPACK computational routine (version 3.7.0) --
108 * -- LAPACK is a software package provided by Univ. of Tennessee, --
109 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
110 * December 2016
111 *
112 * .. Scalar Arguments ..
113  CHARACTER UPLO
114  INTEGER INFO, N, LDA
115 * ..
116 * .. Array Arguments ..
117  COMPLEX*16 A( lda, * ), AP( * )
118 * ..
119 *
120 * =====================================================================
121 *
122 * .. Parameters ..
123 * ..
124 * .. Local Scalars ..
125  LOGICAL LOWER
126  INTEGER I, J, K
127 * ..
128 * .. External Functions ..
129  LOGICAL LSAME
130  EXTERNAL lsame
131 * ..
132 * .. External Subroutines ..
133  EXTERNAL xerbla
134 * ..
135 * .. Executable Statements ..
136 *
137 * Test the input parameters.
138 *
139  info = 0
140  lower = lsame( uplo, 'L' )
141  IF( .NOT.lower .AND. .NOT.lsame( uplo, 'U' ) ) THEN
142  info = -1
143  ELSE IF( n.LT.0 ) THEN
144  info = -2
145  ELSE IF( lda.LT.max( 1, n ) ) THEN
146  info = -4
147  END IF
148  IF( info.NE.0 ) THEN
149  CALL xerbla( 'ZTRTTP', -info )
150  RETURN
151  END IF
152 *
153  IF( lower ) THEN
154  k = 0
155  DO j = 1, n
156  DO i = j, n
157  k = k + 1
158  ap( k ) = a( i, j )
159  END DO
160  END DO
161  ELSE
162  k = 0
163  DO j = 1, n
164  DO i = 1, j
165  k = k + 1
166  ap( k ) = a( i, j )
167  END DO
168  END DO
169  END IF
170 *
171 *
172  RETURN
173 *
174 * End of ZTRTTP
175 *
176  END
subroutine ztrttp(UPLO, N, A, LDA, AP, INFO)
ZTRTTP copies a triangular matrix from the standard full format (TR) to the standard packed format (T...
Definition: ztrttp.f:106
subroutine xerbla(SRNAME, INFO)
XERBLA
Definition: xerbla.f:62