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LAPACK
3.4.1
LAPACK: Linear Algebra PACKage
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00001 *> \brief \b DTRTTP 00002 * 00003 * =========== DOCUMENTATION =========== 00004 * 00005 * Online html documentation available at 00006 * http://www.netlib.org/lapack/explore-html/ 00007 * 00008 *> \htmlonly 00009 *> Download DTRTTP + dependencies 00010 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dtrttp.f"> 00011 *> [TGZ]</a> 00012 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dtrttp.f"> 00013 *> [ZIP]</a> 00014 *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dtrttp.f"> 00015 *> [TXT]</a> 00016 *> \endhtmlonly 00017 * 00018 * Definition: 00019 * =========== 00020 * 00021 * SUBROUTINE DTRTTP( UPLO, N, A, LDA, AP, INFO ) 00022 * 00023 * .. Scalar Arguments .. 00024 * CHARACTER UPLO 00025 * INTEGER INFO, N, LDA 00026 * .. 00027 * .. Array Arguments .. 00028 * DOUBLE PRECISION A( LDA, * ), AP( * ) 00029 * .. 00030 * 00031 * 00032 *> \par Purpose: 00033 * ============= 00034 *> 00035 *> \verbatim 00036 *> 00037 *> DTRTTP copies a triangular matrix A from full format (TR) to standard 00038 *> packed format (TP). 00039 *> \endverbatim 00040 * 00041 * Arguments: 00042 * ========== 00043 * 00044 *> \param[in] UPLO 00045 *> \verbatim 00046 *> UPLO is CHARACTER*1 00047 *> = 'U': A is upper triangular. 00048 *> = 'L': A is lower triangular. 00049 *> \endverbatim 00050 *> 00051 *> \param[in] N 00052 *> \verbatim 00053 *> N is INTEGER 00054 *> The order of the matrices AP and A. N >= 0. 00055 *> \endverbatim 00056 *> 00057 *> \param[in] A 00058 *> \verbatim 00059 *> A is DOUBLE PRECISION array, dimension (LDA,N) 00060 *> On exit, the triangular matrix A. If UPLO = 'U', the leading 00061 *> N-by-N upper triangular part of A contains the upper 00062 *> triangular part of the matrix A, and the strictly lower 00063 *> triangular part of A is not referenced. If UPLO = 'L', the 00064 *> leading N-by-N lower triangular part of A contains the lower 00065 *> triangular part of the matrix A, and the strictly upper 00066 *> triangular part of A is not referenced. 00067 *> \endverbatim 00068 *> 00069 *> \param[in] LDA 00070 *> \verbatim 00071 *> LDA is INTEGER 00072 *> The leading dimension of the array A. LDA >= max(1,N). 00073 *> \endverbatim 00074 *> 00075 *> \param[out] AP 00076 *> \verbatim 00077 *> AP is DOUBLE PRECISION array, dimension (N*(N+1)/2 00078 *> On exit, the upper or lower triangular matrix A, packed 00079 *> columnwise in a linear array. The j-th column of A is stored 00080 *> in the array AP as follows: 00081 *> if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; 00082 *> if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n. 00083 *> \endverbatim 00084 *> 00085 *> \param[out] INFO 00086 *> \verbatim 00087 *> INFO is INTEGER 00088 *> = 0: successful exit 00089 *> < 0: if INFO = -i, the i-th argument had an illegal value 00090 *> \endverbatim 00091 * 00092 * Authors: 00093 * ======== 00094 * 00095 *> \author Univ. of Tennessee 00096 *> \author Univ. of California Berkeley 00097 *> \author Univ. of Colorado Denver 00098 *> \author NAG Ltd. 00099 * 00100 *> \date November 2011 00101 * 00102 *> \ingroup doubleOTHERcomputational 00103 * 00104 * ===================================================================== 00105 SUBROUTINE DTRTTP( UPLO, N, A, LDA, AP, INFO ) 00106 * 00107 * -- LAPACK computational routine (version 3.4.0) -- 00108 * -- LAPACK is a software package provided by Univ. of Tennessee, -- 00109 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 00110 * November 2011 00111 * 00112 * .. Scalar Arguments .. 00113 CHARACTER UPLO 00114 INTEGER INFO, N, LDA 00115 * .. 00116 * .. Array Arguments .. 00117 DOUBLE PRECISION A( LDA, * ), AP( * ) 00118 * .. 00119 * 00120 * ===================================================================== 00121 * 00122 * .. Parameters .. 00123 * .. 00124 * .. Local Scalars .. 00125 LOGICAL LOWER 00126 INTEGER I, J, K 00127 * .. 00128 * .. External Functions .. 00129 LOGICAL LSAME 00130 EXTERNAL LSAME 00131 * .. 00132 * .. External Subroutines .. 00133 EXTERNAL XERBLA 00134 * .. 00135 * .. Executable Statements .. 00136 * 00137 * Test the input parameters. 00138 * 00139 INFO = 0 00140 LOWER = LSAME( UPLO, 'L' ) 00141 IF( .NOT.LOWER .AND. .NOT.LSAME( UPLO, 'U' ) ) THEN 00142 INFO = -1 00143 ELSE IF( N.LT.0 ) THEN 00144 INFO = -2 00145 ELSE IF( LDA.LT.MAX( 1, N ) ) THEN 00146 INFO = -4 00147 END IF 00148 IF( INFO.NE.0 ) THEN 00149 CALL XERBLA( 'DTRTTP', -INFO ) 00150 RETURN 00151 END IF 00152 * 00153 IF( LOWER ) THEN 00154 K = 0 00155 DO J = 1, N 00156 DO I = J, N 00157 K = K + 1 00158 AP( K ) = A( I, J ) 00159 END DO 00160 END DO 00161 ELSE 00162 K = 0 00163 DO J = 1, N 00164 DO I = 1, J 00165 K = K + 1 00166 AP( K ) = A( I, J ) 00167 END DO 00168 END DO 00169 END IF 00170 * 00171 * 00172 RETURN 00173 * 00174 * End of DTRTTP 00175 * 00176 END