#include <cmath>

#include "../gmx_blas.h"
#include "../gmx_lapack.h"

void F77_FUNC(dlasd3, DLASD3)(int*    nl,
                              int*    nr,
                              int*    sqre,
                              int*    k,
                              double* d__,
                              double* q,
                              int*    ldq,
                              double* dsigma,
                              double* u,
                              int*    ldu,
                              double* u2,
                              int*    ldu2,
                              double* vt,
                              int*    ldvt,
                              double* vt2,
                              int*    ldvt2,
                              int*    idxc,
                              int*    ctot,
                              double* z__,
                              int*    info)
{
    int q_dim1, q_offset, u_dim1, u_offset, u2_dim1, u2_offset, vt_dim1, vt_offset, vt2_dim1,
            vt2_offset, i__1, i__2;
    double d__2;

    int    i__, j, m, n, jc;
    double rho;
    int    nlp1, nlp2, nrp1;
    double temp;
    int    ctemp;
    int    ktemp;
    int    c__1 = 1;
    int    c__0 = 0;
    double zero = 0.0;
    double one  = 1.0;

    --d__;
    q_dim1   = *ldq;
    q_offset = 1 + q_dim1;
    q -= q_offset;
    --dsigma;
    u_dim1   = *ldu;
    u_offset = 1 + u_dim1;
    u -= u_offset;
    u2_dim1   = *ldu2;
    u2_offset = 1 + u2_dim1;
    u2 -= u2_offset;
    vt_dim1   = *ldvt;
    vt_offset = 1 + vt_dim1;
    vt -= vt_offset;
    vt2_dim1   = *ldvt2;
    vt2_offset = 1 + vt2_dim1;
    vt2 -= vt2_offset;
    --idxc;
    --ctot;
    --z__;

    /* Function Body */
    *info = 0;

    if (*nl < 1)
    {
        *info = -1;
    }
    else if (*nr < 1)
    {
        *info = -2;
    }
    else if (*sqre != 1 && *sqre != 0)
    {
        *info = -3;
    }

    n    = *nl + *nr + 1;
    m    = n + *sqre;
    nlp1 = *nl + 1;
    nlp2 = *nl + 2;

    if (*k == 1)
    {
        d__[1] = std::abs(z__[1]);
        F77_FUNC(dcopy, DCOPY)(&m, &vt2[vt2_dim1 + 1], ldvt2, &vt[vt_dim1 + 1], ldvt);
        if (z__[1] > 0.)
        {
            F77_FUNC(dcopy, DCOPY)(&n, &u2[u2_dim1 + 1], &c__1, &u[u_dim1 + 1], &c__1);
        }
        else
        {
            i__1 = n;
            for (i__ = 1; i__ <= i__1; ++i__)
            {
                u[i__ + u_dim1] = -u2[i__ + u2_dim1];
            }
        }
        return;
    }

    F77_FUNC(dcopy, DCOPY)(k, &z__[1], &c__1, &q[q_offset], &c__1);

    rho = F77_FUNC(dnrm2, DNRM2)(k, &z__[1], &c__1);
    F77_FUNC(dlascl, DLASCL)("G", &c__0, &c__0, &rho, &one, k, &c__1, &z__[1], k, info);
    rho *= rho;


    i__1 = *k;
    for (j = 1; j <= i__1; ++j)
    {
        F77_FUNC(dlasd4, DLASD4)
        (k, &j, &dsigma[1], &z__[1], &u[j * u_dim1 + 1], &rho, &d__[j], &vt[j * vt_dim1 + 1], info);

        if (*info != 0)
        {
            return;
        }
    }

    i__1 = *k;
    for (i__ = 1; i__ <= i__1; ++i__)
    {
        z__[i__] = u[i__ + *k * u_dim1] * vt[i__ + *k * vt_dim1];
        i__2     = i__ - 1;
        for (j = 1; j <= i__2; ++j)
        {
            z__[i__] *= u[i__ + j * u_dim1] * vt[i__ + j * vt_dim1] / (dsigma[i__] - dsigma[j])
                        / (dsigma[i__] + dsigma[j]);
        }
        i__2 = *k - 1;
        for (j = i__; j <= i__2; ++j)
        {
            z__[i__] *= u[i__ + j * u_dim1] * vt[i__ + j * vt_dim1] / (dsigma[i__] - dsigma[j + 1])
                        / (dsigma[i__] + dsigma[j + 1]);
        }
        d__2     = std::sqrt(std::abs(z__[i__]));
        z__[i__] = (q[i__ + q_dim1] > 0) ? d__2 : -d__2;
    }

    i__1 = *k;
    for (i__ = 1; i__ <= i__1; ++i__)
    {
        vt[i__ * vt_dim1 + 1] = z__[1] / u[i__ * u_dim1 + 1] / vt[i__ * vt_dim1 + 1];
        u[i__ * u_dim1 + 1]   = -1.;
        i__2                  = *k;
        for (j = 2; j <= i__2; ++j)
        {
            vt[j + i__ * vt_dim1] = z__[j] / u[j + i__ * u_dim1] / vt[j + i__ * vt_dim1];
            u[j + i__ * u_dim1]   = dsigma[j] * vt[j + i__ * vt_dim1];
        }
        temp                = F77_FUNC(dnrm2, DNRM2)(k, &u[i__ * u_dim1 + 1], &c__1);
        q[i__ * q_dim1 + 1] = u[i__ * u_dim1 + 1] / temp;
        i__2                = *k;
        for (j = 2; j <= i__2; ++j)
        {
            jc                  = idxc[j];
            q[j + i__ * q_dim1] = u[jc + i__ * u_dim1] / temp;
        }
    }

    if (*k == 2)
    {
        F77_FUNC(dgemm, DGEMM)
        ("N", "N", &n, k, k, &one, &u2[u2_offset], ldu2, &q[q_offset], ldq, &zero, &u[u_offset], ldu);
        goto L100;
    }
    if (ctot[1] > 0)
    {
        F77_FUNC(dgemm, DGEMM)
        ("N", "N", nl, k, &ctot[1], &one, &u2[(u2_dim1 << 1) + 1], ldu2, &q[q_dim1 + 2], ldq, &zero, &u[u_dim1 + 1], ldu);
        if (ctot[3] > 0)
        {
            ktemp = ctot[1] + 2 + ctot[2];
            F77_FUNC(dgemm, DGEMM)
            ("N", "N", nl, k, &ctot[3], &one, &u2[ktemp * u2_dim1 + 1], ldu2, &q[ktemp + q_dim1], ldq, &one, &u[u_dim1 + 1], ldu);
        }
    }
    else if (ctot[3] > 0)
    {
        ktemp = ctot[1] + 2 + ctot[2];
        F77_FUNC(dgemm, DGEMM)
        ("N", "N", nl, k, &ctot[3], &one, &u2[ktemp * u2_dim1 + 1], ldu2, &q[ktemp + q_dim1], ldq, &zero, &u[u_dim1 + 1], ldu);
    }
    else
    {
        F77_FUNC(dlacpy, DLACPY)("F", nl, k, &u2[u2_offset], ldu2, &u[u_offset], ldu);
    }
    F77_FUNC(dcopy, DCOPY)(k, &q[q_dim1 + 1], ldq, &u[nlp1 + u_dim1], ldu);
    ktemp = ctot[1] + 2;
    ctemp = ctot[2] + ctot[3];
    F77_FUNC(dgemm, DGEMM)
    ("N", "N", nr, k, &ctemp, &one, &u2[nlp2 + ktemp * u2_dim1], ldu2, &q[ktemp + q_dim1], ldq, &zero, &u[nlp2 + u_dim1], ldu);

L100:
    i__1 = *k;
    for (i__ = 1; i__ <= i__1; ++i__)
    {
        temp            = F77_FUNC(dnrm2, DNRM2)(k, &vt[i__ * vt_dim1 + 1], &c__1);
        q[i__ + q_dim1] = vt[i__ * vt_dim1 + 1] / temp;
        i__2            = *k;
        for (j = 2; j <= i__2; ++j)
        {
            jc                  = idxc[j];
            q[i__ + j * q_dim1] = vt[jc + i__ * vt_dim1] / temp;
        }
    }

    if (*k == 2)
    {
        F77_FUNC(dgemm, DGEMM)
        ("N", "N", k, &m, k, &one, &q[q_offset], ldq, &vt2[vt2_offset], ldvt2, &zero, &vt[vt_offset], ldvt);
        return;
    }
    ktemp = ctot[1] + 1;
    F77_FUNC(dgemm, DGEMM)
    ("N", "N", k, &nlp1, &ktemp, &one, &q[q_dim1 + 1], ldq, &vt2[vt2_dim1 + 1], ldvt2, &zero, &vt[vt_dim1 + 1], ldvt);
    ktemp = ctot[1] + 2 + ctot[2];
    if (ktemp <= *ldvt2)
    {
        F77_FUNC(dgemm, DGEMM)
        ("N",
         "N",
         k,
         &nlp1,
         &ctot[3],
         &one,
         &q[ktemp * q_dim1 + 1],
         ldq,
         &vt2[ktemp + vt2_dim1],
         ldvt2,
         &one,
         &vt[vt_dim1 + 1],
         ldvt);
    }

    ktemp = ctot[1] + 1;
    nrp1  = *nr + *sqre;
    if (ktemp > 1)
    {
        i__1 = *k;
        for (i__ = 1; i__ <= i__1; ++i__)
        {
            q[i__ + ktemp * q_dim1] = q[i__ + q_dim1];
        }
        i__1 = m;
        for (i__ = nlp2; i__ <= i__1; ++i__)
        {
            vt2[ktemp + i__ * vt2_dim1] = vt2[i__ * vt2_dim1 + 1];
        }
    }
    ctemp = ctot[2] + 1 + ctot[3];
    F77_FUNC(dgemm, DGEMM)
    ("N",
     "N",
     k,
     &nrp1,
     &ctemp,
     &one,
     &q[ktemp * q_dim1 + 1],
     ldq,
     &vt2[ktemp + nlp2 * vt2_dim1],
     ldvt2,
     &zero,
     &vt[nlp2 * vt_dim1 + 1],
     ldvt);

    return;
}
