lammps/lib/linalg/zunm2r.cpp

/* fortran/zunm2r.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 integer c__1 = 1;

/* > \brief \b ZUNM2R multiplies a general matrix by the unitary matrix from a QR factorization determined by
cgeqrf (unblocked algorithm). */

/*  =========== DOCUMENTATION =========== */

/* Online html documentation available at */
/*            http://www.netlib.org/lapack/explore-html/ */

/* > \htmlonly */
/* > Download ZUNM2R + dependencies */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zunm2r.
f"> */
/* > [TGZ]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zunm2r.
f"> */
/* > [ZIP]</a> */
/* > <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zunm2r.
f"> */
/* > [TXT]</a> */
/* > \endhtmlonly */

/*  Definition: */
/*  =========== */

/*       SUBROUTINE ZUNM2R( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, */
/*                          WORK, INFO ) */

/*       .. Scalar Arguments .. */
/*       CHARACTER          SIDE, TRANS */
/*       INTEGER            INFO, K, LDA, LDC, M, N */
/*       .. */
/*       .. Array Arguments .. */
/*       COMPLEX*16         A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * ) */
/*       .. */


/* > \par Purpose: */
/*  ============= */
/* > */
/* > \verbatim */
/* > */
/* > ZUNM2R overwrites the general complex m-by-n matrix C with */
/* > */
/* >       Q * C  if SIDE = 'L' and TRANS = 'N', or */
/* > */
/* >       Q**H* C  if SIDE = 'L' and TRANS = 'C', or */
/* > */
/* >       C * Q  if SIDE = 'R' and TRANS = 'N', or */
/* > */
/* >       C * Q**H if SIDE = 'R' and TRANS = 'C', */
/* > */
/* > where Q is a complex unitary matrix defined as the product of k */
/* > elementary reflectors */
/* > */
/* >       Q = H(1) H(2) . . . H(k) */
/* > */
/* > as returned by ZGEQRF. Q is of order m if SIDE = 'L' and of order n */
/* > if SIDE = 'R'. */
/* > \endverbatim */

/*  Arguments: */
/*  ========== */

/* > \param[in] SIDE */
/* > \verbatim */
/* >          SIDE is CHARACTER*1 */
/* >          = 'L': apply Q or Q**H from the Left */
/* >          = 'R': apply Q or Q**H from the Right */
/* > \endverbatim */
/* > */
/* > \param[in] TRANS */
/* > \verbatim */
/* >          TRANS is CHARACTER*1 */
/* >          = 'N': apply Q  (No transpose) */
/* >          = 'C': apply Q**H (Conjugate transpose) */
/* > \endverbatim */
/* > */
/* > \param[in] M */
/* > \verbatim */
/* >          M is INTEGER */
/* >          The number of rows of the matrix C. M >= 0. */
/* > \endverbatim */
/* > */
/* > \param[in] N */
/* > \verbatim */
/* >          N is INTEGER */
/* >          The number of columns of the matrix C. N >= 0. */
/* > \endverbatim */
/* > */
/* > \param[in] K */
/* > \verbatim */
/* >          K is INTEGER */
/* >          The number of elementary reflectors whose product defines */
/* >          the matrix Q. */
/* >          If SIDE = 'L', M >= K >= 0; */
/* >          if SIDE = 'R', N >= K >= 0. */
/* > \endverbatim */
/* > */
/* > \param[in] A */
/* > \verbatim */
/* >          A is COMPLEX*16 array, dimension (LDA,K) */
/* >          The i-th column must contain the vector which defines the */
/* >          elementary reflector H(i), for i = 1,2,...,k, as returned by */
/* >          ZGEQRF in the first k columns of its array argument A. */
/* >          A is modified by the routine but restored on exit. */
/* > \endverbatim */
/* > */
/* > \param[in] LDA */
/* > \verbatim */
/* >          LDA is INTEGER */
/* >          The leading dimension of the array A. */
/* >          If SIDE = 'L', LDA >= max(1,M); */
/* >          if SIDE = 'R', LDA >= max(1,N). */
/* > \endverbatim */
/* > */
/* > \param[in] TAU */
/* > \verbatim */
/* >          TAU is COMPLEX*16 array, dimension (K) */
/* >          TAU(i) must contain the scalar factor of the elementary */
/* >          reflector H(i), as returned by ZGEQRF. */
/* > \endverbatim */
/* > */
/* > \param[in,out] C */
/* > \verbatim */
/* >          C is COMPLEX*16 array, dimension (LDC,N) */
/* >          On entry, the m-by-n matrix C. */
/* >          On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q. */
/* > \endverbatim */
/* > */
/* > \param[in] LDC */
/* > \verbatim */
/* >          LDC is INTEGER */
/* >          The leading dimension of the array C. LDC >= max(1,M). */
/* > \endverbatim */
/* > */
/* > \param[out] WORK */
/* > \verbatim */
/* >          WORK is COMPLEX*16 array, dimension */
/* >                                   (N) if SIDE = 'L', */
/* >                                   (M) if SIDE = 'R' */
/* > \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. */

/* > \ingroup complex16OTHERcomputational */

/*  ===================================================================== */
/* Subroutine */ int zunm2r_(char *side, char *trans, integer *m, integer *n,
        integer *k, doublecomplex *a, integer *lda, doublecomplex *tau,
        doublecomplex *c__, integer *ldc, doublecomplex *work, integer *info,
        ftnlen side_len, ftnlen trans_len)
{
    /* System generated locals */
    integer a_dim1, a_offset, c_dim1, c_offset, i__1, i__2, i__3;
    doublecomplex z__1;

    /* Builtin functions */
    void d_cnjg(doublecomplex *, doublecomplex *);

    /* Local variables */
    integer i__, i1, i2, i3, ic, jc, mi, ni, nq;
    doublecomplex aii;
    logical left;
    doublecomplex taui;
    extern logical lsame_(char *, char *, ftnlen, ftnlen);
    extern /* Subroutine */ int zlarf_(char *, integer *, integer *,
            doublecomplex *, integer *, doublecomplex *, doublecomplex *,
            integer *, doublecomplex *, ftnlen), xerbla_(char *, integer *,
            ftnlen);
    logical notran;


/*  -- 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 .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Test the input arguments */

    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    --tau;
    c_dim1 = *ldc;
    c_offset = 1 + c_dim1;
    c__ -= c_offset;
    --work;

    /* Function Body */
    *info = 0;
    left = lsame_(side, (char *)"L", (ftnlen)1, (ftnlen)1);
    notran = lsame_(trans, (char *)"N", (ftnlen)1, (ftnlen)1);

/*     NQ is the order of Q */

    if (left) {
        nq = *m;
    } else {
        nq = *n;
    }
    if (! left && ! lsame_(side, (char *)"R", (ftnlen)1, (ftnlen)1)) {
        *info = -1;
    } else if (! notran && ! lsame_(trans, (char *)"C", (ftnlen)1, (ftnlen)1)) {
        *info = -2;
    } else if (*m < 0) {
        *info = -3;
    } else if (*n < 0) {
        *info = -4;
    } else if (*k < 0 || *k > nq) {
        *info = -5;
    } else if (*lda < max(1,nq)) {
        *info = -7;
    } else if (*ldc < max(1,*m)) {
        *info = -10;
    }
    if (*info != 0) {
        i__1 = -(*info);
        xerbla_((char *)"ZUNM2R", &i__1, (ftnlen)6);
        return 0;
    }

/*     Quick return if possible */

    if (*m == 0 || *n == 0 || *k == 0) {
        return 0;
    }

    if (left && ! notran || ! left && notran) {
        i1 = 1;
        i2 = *k;
        i3 = 1;
    } else {
        i1 = *k;
        i2 = 1;
        i3 = -1;
    }

    if (left) {
        ni = *n;
        jc = 1;
    } else {
        mi = *m;
        ic = 1;
    }

    i__1 = i2;
    i__2 = i3;
    for (i__ = i1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
        if (left) {

/*           H(i) or H(i)**H is applied to C(i:m,1:n) */

            mi = *m - i__ + 1;
            ic = i__;
        } else {

/*           H(i) or H(i)**H is applied to C(1:m,i:n) */

            ni = *n - i__ + 1;
            jc = i__;
        }

/*        Apply H(i) or H(i)**H */

        if (notran) {
            i__3 = i__;
            taui.r = tau[i__3].r, taui.i = tau[i__3].i;
        } else {
            d_cnjg(&z__1, &tau[i__]);
            taui.r = z__1.r, taui.i = z__1.i;
        }
        i__3 = i__ + i__ * a_dim1;
        aii.r = a[i__3].r, aii.i = a[i__3].i;
        i__3 = i__ + i__ * a_dim1;
        a[i__3].r = 1., a[i__3].i = 0.;
        zlarf_(side, &mi, &ni, &a[i__ + i__ * a_dim1], &c__1, &taui, &c__[ic
                + jc * c_dim1], ldc, &work[1], (ftnlen)1);
        i__3 = i__ + i__ * a_dim1;
        a[i__3].r = aii.r, a[i__3].i = aii.i;
/* L10: */
    }
    return 0;

/*     End of ZUNM2R */

} /* zunm2r_ */

#ifdef __cplusplus
        }
#endif