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version 1.6, 2011/07/22 07:38:09 version 1.7, 2011/11/21 20:43:01
Line 1 Line 1
       SUBROUTINE DPFTRS( TRANSR, UPLO, N, NRHS, A, B, LDB, INFO )  *> \brief \b DPFTRS
 *  *
 *  -- LAPACK routine (version 3.3.1)                                    --  *  =========== DOCUMENTATION ===========
 *  *
 *  -- Contributed by Fred Gustavson of the IBM Watson Research Center --  * Online html documentation available at 
 *  -- April 2011                                                      --  *            http://www.netlib.org/lapack/explore-html/ 
 *  *
   *> \htmlonly
   *> Download DPFTRS + dependencies 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dpftrs.f"> 
   *> [TGZ]</a> 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dpftrs.f"> 
   *> [ZIP]</a> 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dpftrs.f"> 
   *> [TXT]</a>
   *> \endhtmlonly 
   *
   *  Definition:
   *  ===========
   *
   *       SUBROUTINE DPFTRS( TRANSR, UPLO, N, NRHS, A, B, LDB, INFO )
   * 
   *       .. Scalar Arguments ..
   *       CHARACTER          TRANSR, UPLO
   *       INTEGER            INFO, LDB, N, NRHS
   *       ..
   *       .. Array Arguments ..
   *       DOUBLE PRECISION   A( 0: * ), B( LDB, * )
   *       ..
   *  
   *
   *> \par Purpose:
   *  =============
   *>
   *> \verbatim
   *>
   *> DPFTRS solves a system of linear equations A*X = B with a symmetric
   *> positive definite matrix A using the Cholesky factorization
   *> A = U**T*U or A = L*L**T computed by DPFTRF.
   *> \endverbatim
   *
   *  Arguments:
   *  ==========
   *
   *> \param[in] TRANSR
   *> \verbatim
   *>          TRANSR is CHARACTER*1
   *>          = 'N':  The Normal TRANSR of RFP A is stored;
   *>          = 'T':  The Transpose TRANSR of RFP A is stored.
   *> \endverbatim
   *>
   *> \param[in] UPLO
   *> \verbatim
   *>          UPLO is CHARACTER*1
   *>          = 'U':  Upper triangle of RFP A is stored;
   *>          = 'L':  Lower triangle of RFP A is stored.
   *> \endverbatim
   *>
   *> \param[in] N
   *> \verbatim
   *>          N is INTEGER
   *>          The order of the matrix A.  N >= 0.
   *> \endverbatim
   *>
   *> \param[in] NRHS
   *> \verbatim
   *>          NRHS is INTEGER
   *>          The number of right hand sides, i.e., the number of columns
   *>          of the matrix B.  NRHS >= 0.
   *> \endverbatim
   *>
   *> \param[in] A
   *> \verbatim
   *>          A is DOUBLE PRECISION array, dimension ( N*(N+1)/2 ).
   *>          The triangular factor U or L from the Cholesky factorization
   *>          of RFP A = U**T*U or RFP A = L*L**T, as computed by DPFTRF.
   *>          See note below for more details about RFP A.
   *> \endverbatim
   *>
   *> \param[in,out] B
   *> \verbatim
   *>          B is DOUBLE PRECISION array, dimension (LDB,NRHS)
   *>          On entry, the right hand side matrix B.
   *>          On exit, the solution matrix X.
   *> \endverbatim
   *>
   *> \param[in] LDB
   *> \verbatim
   *>          LDB is INTEGER
   *>          The leading dimension of the array B.  LDB >= max(1,N).
   *> \endverbatim
   *>
   *> \param[out] INFO
   *> \verbatim
   *>          INFO is INTEGER
   *>          = 0:  successful exit
   *>          < 0:  if INFO = -i, the i-th argument had an illegal value
   *> \endverbatim
   *
   *  Authors:
   *  ========
   *
   *> \author Univ. of Tennessee 
   *> \author Univ. of California Berkeley 
   *> \author Univ. of Colorado Denver 
   *> \author NAG Ltd. 
   *
   *> \date November 2011
   *
   *> \ingroup doubleOTHERcomputational
   *
   *> \par Further Details:
   *  =====================
   *>
   *> \verbatim
   *>
   *>  We first consider Rectangular Full Packed (RFP) Format when N is
   *>  even. We give an example where N = 6.
   *>
   *>      AP is Upper             AP is Lower
   *>
   *>   00 01 02 03 04 05       00
   *>      11 12 13 14 15       10 11
   *>         22 23 24 25       20 21 22
   *>            33 34 35       30 31 32 33
   *>               44 45       40 41 42 43 44
   *>                  55       50 51 52 53 54 55
   *>
   *>
   *>  Let TRANSR = 'N'. RFP holds AP as follows:
   *>  For UPLO = 'U' the upper trapezoid A(0:5,0:2) consists of the last
   *>  three columns of AP upper. The lower triangle A(4:6,0:2) consists of
   *>  the transpose of the first three columns of AP upper.
   *>  For UPLO = 'L' the lower trapezoid A(1:6,0:2) consists of the first
   *>  three columns of AP lower. The upper triangle A(0:2,0:2) consists of
   *>  the transpose of the last three columns of AP lower.
   *>  This covers the case N even and TRANSR = 'N'.
   *>
   *>         RFP A                   RFP A
   *>
   *>        03 04 05                33 43 53
   *>        13 14 15                00 44 54
   *>        23 24 25                10 11 55
   *>        33 34 35                20 21 22
   *>        00 44 45                30 31 32
   *>        01 11 55                40 41 42
   *>        02 12 22                50 51 52
   *>
   *>  Now let TRANSR = 'T'. RFP A in both UPLO cases is just the
   *>  transpose of RFP A above. One therefore gets:
   *>
   *>
   *>           RFP A                   RFP A
   *>
   *>     03 13 23 33 00 01 02    33 00 10 20 30 40 50
   *>     04 14 24 34 44 11 12    43 44 11 21 31 41 51
   *>     05 15 25 35 45 55 22    53 54 55 22 32 42 52
   *>
   *>
   *>  We then consider Rectangular Full Packed (RFP) Format when N is
   *>  odd. We give an example where N = 5.
   *>
   *>     AP is Upper                 AP is Lower
   *>
   *>   00 01 02 03 04              00
   *>      11 12 13 14              10 11
   *>         22 23 24              20 21 22
   *>            33 34              30 31 32 33
   *>               44              40 41 42 43 44
   *>
   *>
   *>  Let TRANSR = 'N'. RFP holds AP as follows:
   *>  For UPLO = 'U' the upper trapezoid A(0:4,0:2) consists of the last
   *>  three columns of AP upper. The lower triangle A(3:4,0:1) consists of
   *>  the transpose of the first two columns of AP upper.
   *>  For UPLO = 'L' the lower trapezoid A(0:4,0:2) consists of the first
   *>  three columns of AP lower. The upper triangle A(0:1,1:2) consists of
   *>  the transpose of the last two columns of AP lower.
   *>  This covers the case N odd and TRANSR = 'N'.
   *>
   *>         RFP A                   RFP A
   *>
   *>        02 03 04                00 33 43
   *>        12 13 14                10 11 44
   *>        22 23 24                20 21 22
   *>        00 33 34                30 31 32
   *>        01 11 44                40 41 42
   *>
   *>  Now let TRANSR = 'T'. RFP A in both UPLO cases is just the
   *>  transpose of RFP A above. One therefore gets:
   *>
   *>           RFP A                   RFP A
   *>
   *>     02 12 22 00 01             00 10 20 30 40 50
   *>     03 13 23 33 11             33 11 21 31 41 51
   *>     04 14 24 34 44             43 44 22 32 42 52
   *> \endverbatim
   *>
   *  =====================================================================
         SUBROUTINE DPFTRS( TRANSR, UPLO, N, NRHS, A, B, LDB, INFO )
   *
   *  -- LAPACK computational routine (version 3.4.0) --
 *  -- LAPACK is a software package provided by Univ. of Tennessee,    --  *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
 *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--  *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
   *     November 2011
 *  *
 *     .. Scalar Arguments ..  *     .. Scalar Arguments ..
       CHARACTER          TRANSR, UPLO        CHARACTER          TRANSR, UPLO
Line 16 Line 212
       DOUBLE PRECISION   A( 0: * ), B( LDB, * )        DOUBLE PRECISION   A( 0: * ), B( LDB, * )
 *     ..  *     ..
 *  *
 *  Purpose  
 *  =======  
 *  
 *  DPFTRS solves a system of linear equations A*X = B with a symmetric  
 *  positive definite matrix A using the Cholesky factorization  
 *  A = U**T*U or A = L*L**T computed by DPFTRF.  
 *  
 *  Arguments  
 *  =========  
 *  
 *  TRANSR  (input) CHARACTER*1  
 *          = 'N':  The Normal TRANSR of RFP A is stored;  
 *          = 'T':  The Transpose TRANSR of RFP A is stored.  
 *  
 *  UPLO    (input) CHARACTER*1  
 *          = 'U':  Upper triangle of RFP A is stored;  
 *          = 'L':  Lower triangle of RFP A is stored.  
 *  
 *  N       (input) INTEGER  
 *          The order of the matrix A.  N >= 0.  
 *  
 *  NRHS    (input) INTEGER  
 *          The number of right hand sides, i.e., the number of columns  
 *          of the matrix B.  NRHS >= 0.  
 *  
 *  A       (input) DOUBLE PRECISION array, dimension ( N*(N+1)/2 ).  
 *          The triangular factor U or L from the Cholesky factorization  
 *          of RFP A = U**T*U or RFP A = L*L**T, as computed by DPFTRF.  
 *          See note below for more details about RFP A.  
 *  
 *  B       (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)  
 *          On entry, the right hand side matrix B.  
 *          On exit, the solution matrix X.  
 *  
 *  LDB     (input) INTEGER  
 *          The leading dimension of the array B.  LDB >= max(1,N).  
 *  
 *  INFO    (output) INTEGER  
 *          = 0:  successful exit  
 *          < 0:  if INFO = -i, the i-th argument had an illegal value  
 *  
 *  Further Details  
 *  ===============  
 *  
 *  We first consider Rectangular Full Packed (RFP) Format when N is  
 *  even. We give an example where N = 6.  
 *  
 *      AP is Upper             AP is Lower  
 *  
 *   00 01 02 03 04 05       00  
 *      11 12 13 14 15       10 11  
 *         22 23 24 25       20 21 22  
 *            33 34 35       30 31 32 33  
 *               44 45       40 41 42 43 44  
 *                  55       50 51 52 53 54 55  
 *  
 *  
 *  Let TRANSR = 'N'. RFP holds AP as follows:  
 *  For UPLO = 'U' the upper trapezoid A(0:5,0:2) consists of the last  
 *  three columns of AP upper. The lower triangle A(4:6,0:2) consists of  
 *  the transpose of the first three columns of AP upper.  
 *  For UPLO = 'L' the lower trapezoid A(1:6,0:2) consists of the first  
 *  three columns of AP lower. The upper triangle A(0:2,0:2) consists of  
 *  the transpose of the last three columns of AP lower.  
 *  This covers the case N even and TRANSR = 'N'.  
 *  
 *         RFP A                   RFP A  
 *  
 *        03 04 05                33 43 53  
 *        13 14 15                00 44 54  
 *        23 24 25                10 11 55  
 *        33 34 35                20 21 22  
 *        00 44 45                30 31 32  
 *        01 11 55                40 41 42  
 *        02 12 22                50 51 52  
 *  
 *  Now let TRANSR = 'T'. RFP A in both UPLO cases is just the  
 *  transpose of RFP A above. One therefore gets:  
 *  
 *  
 *           RFP A                   RFP A  
 *  
 *     03 13 23 33 00 01 02    33 00 10 20 30 40 50  
 *     04 14 24 34 44 11 12    43 44 11 21 31 41 51  
 *     05 15 25 35 45 55 22    53 54 55 22 32 42 52  
 *  
 *  
 *  We then consider Rectangular Full Packed (RFP) Format when N is  
 *  odd. We give an example where N = 5.  
 *  
 *     AP is Upper                 AP is Lower  
 *  
 *   00 01 02 03 04              00  
 *      11 12 13 14              10 11  
 *         22 23 24              20 21 22  
 *            33 34              30 31 32 33  
 *               44              40 41 42 43 44  
 *  
 *  
 *  Let TRANSR = 'N'. RFP holds AP as follows:  
 *  For UPLO = 'U' the upper trapezoid A(0:4,0:2) consists of the last  
 *  three columns of AP upper. The lower triangle A(3:4,0:1) consists of  
 *  the transpose of the first two columns of AP upper.  
 *  For UPLO = 'L' the lower trapezoid A(0:4,0:2) consists of the first  
 *  three columns of AP lower. The upper triangle A(0:1,1:2) consists of  
 *  the transpose of the last two columns of AP lower.  
 *  This covers the case N odd and TRANSR = 'N'.  
 *  
 *         RFP A                   RFP A  
 *  
 *        02 03 04                00 33 43  
 *        12 13 14                10 11 44  
 *        22 23 24                20 21 22  
 *        00 33 34                30 31 32  
 *        01 11 44                40 41 42  
 *  
 *  Now let TRANSR = 'T'. RFP A in both UPLO cases is just the  
 *  transpose of RFP A above. One therefore gets:  
 *  
 *           RFP A                   RFP A  
 *  
 *     02 12 22 00 01             00 10 20 30 40 50  
 *     03 13 23 33 11             33 11 21 31 41 51  
 *     04 14 24 34 44             43 44 22 32 42 52  
 *  
 *  =====================================================================  *  =====================================================================
 *  *
 *     .. Parameters ..  *     .. Parameters ..
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  Added in v.1.7

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