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lammps/lib/linalg/ztptri.cpp
Axel Kohlmeyer 1e8b2ad5a0 whitespace fixes
2022-12-28 13:48:43 -05:00

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/* fortran/ztptri.f -- translated by f2c (version 20200916).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#ifdef __cplusplus
extern "C" {
#endif
#include "lmp_f2c.h"
/* Table of constant values */
static doublecomplex c_b1 = {1.,0.};
static integer c__1 = 1;
/* > \brief \b ZTPTRI */
/* =========== DOCUMENTATION =========== */
/* Online html documentation available at */
/* http://www.netlib.org/lapack/explore-html/ */
/* > \htmlonly */
/* > Download ZTPTRI + dependencies */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/ztptri.
f"> */
/* > [TGZ]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/ztptri.
f"> */
/* > [ZIP]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/ztptri.
f"> */
/* > [TXT]</a> */
/* > \endhtmlonly */
/* Definition: */
/* =========== */
/* SUBROUTINE ZTPTRI( UPLO, DIAG, N, AP, INFO ) */
/* .. Scalar Arguments .. */
/* CHARACTER DIAG, UPLO */
/* INTEGER INFO, N */
/* .. */
/* .. Array Arguments .. */
/* COMPLEX*16 AP( * ) */
/* .. */
/* > \par Purpose: */
/* ============= */
/* > */
/* > \verbatim */
/* > */
/* > ZTPTRI computes the inverse of a complex upper or lower triangular */
/* > matrix A stored in packed format. */
/* > \endverbatim */
/* Arguments: */
/* ========== */
/* > \param[in] UPLO */
/* > \verbatim */
/* > UPLO is CHARACTER*1 */
/* > = 'U': A is upper triangular; */
/* > = 'L': A is lower triangular. */
/* > \endverbatim */
/* > */
/* > \param[in] DIAG */
/* > \verbatim */
/* > DIAG is CHARACTER*1 */
/* > = 'N': A is non-unit triangular; */
/* > = 'U': A is unit triangular. */
/* > \endverbatim */
/* > */
/* > \param[in] N */
/* > \verbatim */
/* > N is INTEGER */
/* > The order of the matrix A. N >= 0. */
/* > \endverbatim */
/* > */
/* > \param[in,out] AP */
/* > \verbatim */
/* > AP is COMPLEX*16 array, dimension (N*(N+1)/2) */
/* > On entry, the upper or lower triangular matrix A, stored */
/* > columnwise in a linear array. The j-th column of A is stored */
/* > in the array AP as follows: */
/* > if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; */
/* > if UPLO = 'L', AP(i + (j-1)*((2*n-j)/2) = A(i,j) for j<=i<=n. */
/* > See below for further details. */
/* > On exit, the (triangular) inverse of the original matrix, in */
/* > the same packed storage format. */
/* > \endverbatim */
/* > */
/* > \param[out] INFO */
/* > \verbatim */
/* > INFO is INTEGER */
/* > = 0: successful exit */
/* > < 0: if INFO = -i, the i-th argument had an illegal value */
/* > > 0: if INFO = i, A(i,i) is exactly zero. The triangular */
/* > matrix is singular and its inverse can not be computed. */
/* > \endverbatim */
/* Authors: */
/* ======== */
/* > \author Univ. of Tennessee */
/* > \author Univ. of California Berkeley */
/* > \author Univ. of Colorado Denver */
/* > \author NAG Ltd. */
/* > \ingroup complex16OTHERcomputational */
/* > \par Further Details: */
/* ===================== */
/* > */
/* > \verbatim */
/* > */
/* > A triangular matrix A can be transferred to packed storage using one */
/* > of the following program segments: */
/* > */
/* > UPLO = 'U': UPLO = 'L': */
/* > */
/* > JC = 1 JC = 1 */
/* > DO 2 J = 1, N DO 2 J = 1, N */
/* > DO 1 I = 1, J DO 1 I = J, N */
/* > AP(JC+I-1) = A(I,J) AP(JC+I-J) = A(I,J) */
/* > 1 CONTINUE 1 CONTINUE */
/* > JC = JC + J JC = JC + N - J + 1 */
/* > 2 CONTINUE 2 CONTINUE */
/* > \endverbatim */
/* > */
/* ===================================================================== */
/* Subroutine */ int ztptri_(char *uplo, char *diag, integer *n,
doublecomplex *ap, integer *info, ftnlen uplo_len, ftnlen diag_len)
{
/* System generated locals */
integer i__1, i__2;
doublecomplex z__1;
/* Builtin functions */
void z_div(doublecomplex *, doublecomplex *, doublecomplex *);
/* Local variables */
integer j, jc, jj;
doublecomplex ajj;
extern logical lsame_(char *, char *, ftnlen, ftnlen);
extern /* Subroutine */ int zscal_(integer *, doublecomplex *,
doublecomplex *, integer *);
logical upper;
extern /* Subroutine */ int ztpmv_(char *, char *, char *, integer *,
doublecomplex *, doublecomplex *, integer *, ftnlen, ftnlen,
ftnlen), xerbla_(char *, integer *, ftnlen);
integer jclast;
logical nounit;
/* -- LAPACK computational routine -- */
/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
--ap;
/* Function Body */
*info = 0;
upper = lsame_(uplo, (char *)"U", (ftnlen)1, (ftnlen)1);
nounit = lsame_(diag, (char *)"N", (ftnlen)1, (ftnlen)1);
if (! upper && ! lsame_(uplo, (char *)"L", (ftnlen)1, (ftnlen)1)) {
*info = -1;
} else if (! nounit && ! lsame_(diag, (char *)"U", (ftnlen)1, (ftnlen)1)) {
*info = -2;
} else if (*n < 0) {
*info = -3;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_((char *)"ZTPTRI", &i__1, (ftnlen)6);
return 0;
}
/* Check for singularity if non-unit. */
if (nounit) {
if (upper) {
jj = 0;
i__1 = *n;
for (*info = 1; *info <= i__1; ++(*info)) {
jj += *info;
i__2 = jj;
if (ap[i__2].r == 0. && ap[i__2].i == 0.) {
return 0;
}
/* L10: */
}
} else {
jj = 1;
i__1 = *n;
for (*info = 1; *info <= i__1; ++(*info)) {
i__2 = jj;
if (ap[i__2].r == 0. && ap[i__2].i == 0.) {
return 0;
}
jj = jj + *n - *info + 1;
/* L20: */
}
}
*info = 0;
}
if (upper) {
/* Compute inverse of upper triangular matrix. */
jc = 1;
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
if (nounit) {
i__2 = jc + j - 1;
z_div(&z__1, &c_b1, &ap[jc + j - 1]);
ap[i__2].r = z__1.r, ap[i__2].i = z__1.i;
i__2 = jc + j - 1;
z__1.r = -ap[i__2].r, z__1.i = -ap[i__2].i;
ajj.r = z__1.r, ajj.i = z__1.i;
} else {
z__1.r = -1., z__1.i = -0.;
ajj.r = z__1.r, ajj.i = z__1.i;
}
/* Compute elements 1:j-1 of j-th column. */
i__2 = j - 1;
ztpmv_((char *)"Upper", (char *)"No transpose", diag, &i__2, &ap[1], &ap[jc], &
c__1, (ftnlen)5, (ftnlen)12, (ftnlen)1);
i__2 = j - 1;
zscal_(&i__2, &ajj, &ap[jc], &c__1);
jc += j;
/* L30: */
}
} else {
/* Compute inverse of lower triangular matrix. */
jc = *n * (*n + 1) / 2;
for (j = *n; j >= 1; --j) {
if (nounit) {
i__1 = jc;
z_div(&z__1, &c_b1, &ap[jc]);
ap[i__1].r = z__1.r, ap[i__1].i = z__1.i;
i__1 = jc;
z__1.r = -ap[i__1].r, z__1.i = -ap[i__1].i;
ajj.r = z__1.r, ajj.i = z__1.i;
} else {
z__1.r = -1., z__1.i = -0.;
ajj.r = z__1.r, ajj.i = z__1.i;
}
if (j < *n) {
/* Compute elements j+1:n of j-th column. */
i__1 = *n - j;
ztpmv_((char *)"Lower", (char *)"No transpose", diag, &i__1, &ap[jclast], &ap[
jc + 1], &c__1, (ftnlen)5, (ftnlen)12, (ftnlen)1);
i__1 = *n - j;
zscal_(&i__1, &ajj, &ap[jc + 1], &c__1);
}
jclast = jc;
jc = jc - *n + j - 2;
/* L40: */
}
}
return 0;
/* End of ZTPTRI */
} /* ztptri_ */
#ifdef __cplusplus
}
#endif