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version 1.10, 2011/11/21 22:19:31
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version 1.20, 2023/08/07 08:38:54
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| *> \brief \b DLAGTS |
*> \brief \b DLAGTS solves the system of equations (T-λI)x = y or (T-λI)Tx = y,where T is a general tridiagonal matrix and λ a scalar, using the LU factorization computed by slagtf. |
| * |
* |
| * =========== DOCUMENTATION =========== |
* =========== DOCUMENTATION =========== |
| * |
* |
| * Online html documentation available at |
* Online html documentation available at |
| * http://www.netlib.org/lapack/explore-html/ |
* http://www.netlib.org/lapack/explore-html/ |
| * |
* |
| *> \htmlonly |
*> \htmlonly |
| *> Download DLAGTS + dependencies |
*> Download DLAGTS + dependencies |
| *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlagts.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlagts.f"> |
| *> [TGZ]</a> |
*> [TGZ]</a> |
| *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlagts.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlagts.f"> |
| *> [ZIP]</a> |
*> [ZIP]</a> |
| *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlagts.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlagts.f"> |
| *> [TXT]</a> |
*> [TXT]</a> |
| *> \endhtmlonly |
*> \endhtmlonly |
| * |
* |
| * Definition: |
* Definition: |
| * =========== |
* =========== |
| * |
* |
| * SUBROUTINE DLAGTS( JOB, N, A, B, C, D, IN, Y, TOL, INFO ) |
* SUBROUTINE DLAGTS( JOB, N, A, B, C, D, IN, Y, TOL, INFO ) |
| * |
* |
| * .. Scalar Arguments .. |
* .. Scalar Arguments .. |
| * INTEGER INFO, JOB, N |
* INTEGER INFO, JOB, N |
| * DOUBLE PRECISION TOL |
* DOUBLE PRECISION TOL |
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| * INTEGER IN( * ) |
* INTEGER IN( * ) |
| * DOUBLE PRECISION A( * ), B( * ), C( * ), D( * ), Y( * ) |
* DOUBLE PRECISION A( * ), B( * ), C( * ), D( * ), Y( * ) |
| * .. |
* .. |
| * |
* |
| * |
* |
| *> \par Purpose: |
*> \par Purpose: |
| * ============= |
* ============= |
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| *> \param[in,out] TOL |
*> \param[in,out] TOL |
| *> \verbatim |
*> \verbatim |
| *> TOL is DOUBLE PRECISION |
*> TOL is DOUBLE PRECISION |
| *> On entry, with JOB .lt. 0, TOL should be the minimum |
*> On entry, with JOB < 0, TOL should be the minimum |
| *> perturbation to be made to very small diagonal elements of U. |
*> perturbation to be made to very small diagonal elements of U. |
| *> TOL should normally be chosen as about eps*norm(U), where eps |
*> TOL should normally be chosen as about eps*norm(U), where eps |
| *> is the relative machine precision, but if TOL is supplied as |
*> is the relative machine precision, but if TOL is supplied as |
| *> non-positive, then it is reset to eps*max( abs( u(i,j) ) ). |
*> non-positive, then it is reset to eps*max( abs( u(i,j) ) ). |
| *> If JOB .gt. 0 then TOL is not referenced. |
*> If JOB > 0 then TOL is not referenced. |
| *> |
*> |
| *> On exit, TOL is changed as described above, only if TOL is |
*> On exit, TOL is changed as described above, only if TOL is |
| *> non-positive on entry. Otherwise TOL is unchanged. |
*> non-positive on entry. Otherwise TOL is unchanged. |
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| *> \param[out] INFO |
*> \param[out] INFO |
| *> \verbatim |
*> \verbatim |
| *> INFO is INTEGER |
*> INFO is INTEGER |
| *> = 0 : successful exit |
*> = 0: successful exit |
| *> .lt. 0: if INFO = -i, the i-th argument had an illegal value |
*> < 0: if INFO = -i, the i-th argument had an illegal value |
| *> .gt. 0: overflow would occur when computing the INFO(th) |
*> > 0: overflow would occur when computing the INFO(th) |
| *> element of the solution vector x. This can only occur |
*> element of the solution vector x. This can only occur |
| *> when JOB is supplied as positive and either means |
*> when JOB is supplied as positive and either means |
| *> that a diagonal element of U is very small, or that |
*> that a diagonal element of U is very small, or that |
| *> the elements of the right-hand side vector y are very |
*> the elements of the right-hand side vector y are very |
| *> large. |
*> large. |
| *> \endverbatim |
*> \endverbatim |
| * |
* |
| * Authors: |
* Authors: |
| * ======== |
* ======== |
| * |
* |
| *> \author Univ. of Tennessee |
*> \author Univ. of Tennessee |
| *> \author Univ. of California Berkeley |
*> \author Univ. of California Berkeley |
| *> \author Univ. of Colorado Denver |
*> \author Univ. of Colorado Denver |
| *> \author NAG Ltd. |
*> \author NAG Ltd. |
| * |
|
| *> \date November 2011 |
|
| * |
* |
| *> \ingroup auxOTHERauxiliary |
*> \ingroup OTHERauxiliary |
| * |
* |
| * ===================================================================== |
* ===================================================================== |
| SUBROUTINE DLAGTS( JOB, N, A, B, C, D, IN, Y, TOL, INFO ) |
SUBROUTINE DLAGTS( JOB, N, A, B, C, D, IN, Y, TOL, INFO ) |
| * |
* |
| * -- LAPACK auxiliary routine (version 3.4.0) -- |
* -- LAPACK auxiliary routine -- |
| * -- 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 .. |
| INTEGER INFO, JOB, N |
INTEGER INFO, JOB, N |
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