version 1.5, 2010/08/07 13:22:28
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version 1.9, 2011/11/21 22:19:42
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*> \brief \b DTPTRI |
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* |
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* =========== DOCUMENTATION =========== |
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* |
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* Online html documentation available at |
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* http://www.netlib.org/lapack/explore-html/ |
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* |
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*> \htmlonly |
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*> Download DTPTRI + dependencies |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dtptri.f"> |
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*> [TGZ]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dtptri.f"> |
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*> [ZIP]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dtptri.f"> |
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*> [TXT]</a> |
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*> \endhtmlonly |
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* |
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* Definition: |
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* =========== |
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* |
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* SUBROUTINE DTPTRI( UPLO, DIAG, N, AP, INFO ) |
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* |
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* .. Scalar Arguments .. |
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* CHARACTER DIAG, UPLO |
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* INTEGER INFO, N |
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* .. |
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* .. Array Arguments .. |
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* DOUBLE PRECISION AP( * ) |
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* .. |
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* |
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* |
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*> \par Purpose: |
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* ============= |
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*> |
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*> \verbatim |
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*> |
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*> DTPTRI computes the inverse of a real upper or lower triangular |
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*> matrix A stored in packed format. |
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*> \endverbatim |
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* |
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* Arguments: |
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* ========== |
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* |
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*> \param[in] UPLO |
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*> \verbatim |
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*> UPLO is CHARACTER*1 |
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*> = 'U': A is upper triangular; |
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*> = 'L': A is lower triangular. |
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*> \endverbatim |
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*> |
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*> \param[in] DIAG |
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*> \verbatim |
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*> DIAG is CHARACTER*1 |
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*> = 'N': A is non-unit triangular; |
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*> = 'U': A is unit triangular. |
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*> \endverbatim |
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*> |
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*> \param[in] N |
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*> \verbatim |
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*> N is INTEGER |
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*> The order of the matrix A. N >= 0. |
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*> \endverbatim |
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*> |
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*> \param[in,out] AP |
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*> \verbatim |
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*> AP is DOUBLE PRECISION array, dimension (N*(N+1)/2) |
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*> On entry, the upper or lower triangular matrix A, stored |
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*> columnwise in a linear array. The j-th column of A is stored |
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*> in the array AP as follows: |
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*> if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; |
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*> if UPLO = 'L', AP(i + (j-1)*((2*n-j)/2) = A(i,j) for j<=i<=n. |
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*> See below for further details. |
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*> On exit, the (triangular) inverse of the original matrix, in |
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*> the same packed storage format. |
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*> \endverbatim |
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*> |
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*> \param[out] INFO |
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*> \verbatim |
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*> INFO is INTEGER |
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*> = 0: successful exit |
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*> < 0: if INFO = -i, the i-th argument had an illegal value |
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*> > 0: if INFO = i, A(i,i) is exactly zero. The triangular |
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*> matrix is singular and its inverse can not be computed. |
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*> \endverbatim |
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* |
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* Authors: |
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* ======== |
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* |
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*> \author Univ. of Tennessee |
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*> \author Univ. of California Berkeley |
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*> \author Univ. of Colorado Denver |
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*> \author NAG Ltd. |
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* |
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*> \date November 2011 |
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* |
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*> \ingroup doubleOTHERcomputational |
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* |
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*> \par Further Details: |
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* ===================== |
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*> |
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*> \verbatim |
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*> |
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*> A triangular matrix A can be transferred to packed storage using one |
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*> of the following program segments: |
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*> |
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*> UPLO = 'U': UPLO = 'L': |
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*> |
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*> JC = 1 JC = 1 |
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*> DO 2 J = 1, N DO 2 J = 1, N |
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*> DO 1 I = 1, J DO 1 I = J, N |
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*> AP(JC+I-1) = A(I,J) AP(JC+I-J) = A(I,J) |
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*> 1 CONTINUE 1 CONTINUE |
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*> JC = JC + J JC = JC + N - J + 1 |
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*> 2 CONTINUE 2 CONTINUE |
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*> \endverbatim |
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*> |
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* ===================================================================== |
SUBROUTINE DTPTRI( UPLO, DIAG, N, AP, INFO ) |
SUBROUTINE DTPTRI( UPLO, DIAG, N, AP, INFO ) |
* |
* |
* -- LAPACK routine (version 3.2) -- |
* -- 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 2006 |
* November 2011 |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
CHARACTER DIAG, UPLO |
CHARACTER DIAG, UPLO |
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DOUBLE PRECISION AP( * ) |
DOUBLE PRECISION AP( * ) |
* .. |
* .. |
* |
* |
* Purpose |
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* ======= |
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* |
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* DTPTRI computes the inverse of a real upper or lower triangular |
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* matrix A stored in packed format. |
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* |
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* Arguments |
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* ========= |
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* |
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* UPLO (input) CHARACTER*1 |
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* = 'U': A is upper triangular; |
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* = 'L': A is lower triangular. |
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* |
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* DIAG (input) CHARACTER*1 |
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* = 'N': A is non-unit triangular; |
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* = 'U': A is unit triangular. |
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* |
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* N (input) INTEGER |
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* The order of the matrix A. N >= 0. |
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* |
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* AP (input/output) DOUBLE PRECISION array, dimension (N*(N+1)/2) |
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* On entry, the upper or lower triangular matrix A, stored |
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* columnwise in a linear array. The j-th column of A is stored |
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* in the array AP as follows: |
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* if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; |
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* if UPLO = 'L', AP(i + (j-1)*((2*n-j)/2) = A(i,j) for j<=i<=n. |
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* See below for further details. |
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* On exit, the (triangular) inverse of the original matrix, in |
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* the same packed storage format. |
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* |
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* INFO (output) INTEGER |
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* = 0: successful exit |
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* < 0: if INFO = -i, the i-th argument had an illegal value |
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* > 0: if INFO = i, A(i,i) is exactly zero. The triangular |
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* matrix is singular and its inverse can not be computed. |
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* |
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* Further Details |
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* =============== |
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* |
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* A triangular matrix A can be transferred to packed storage using one |
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* of the following program segments: |
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* |
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* UPLO = 'U': UPLO = 'L': |
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* |
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* JC = 1 JC = 1 |
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* DO 2 J = 1, N DO 2 J = 1, N |
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* DO 1 I = 1, J DO 1 I = J, N |
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* AP(JC+I-1) = A(I,J) AP(JC+I-J) = A(I,J) |
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* 1 CONTINUE 1 CONTINUE |
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* JC = JC + J JC = JC + N - J + 1 |
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* 2 CONTINUE 2 CONTINUE |
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* |
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* ===================================================================== |
* ===================================================================== |
* |
* |
* .. Parameters .. |
* .. Parameters .. |