zqrdc.c

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/*     compute the norms of the free columns. */

/*<       if (pu .lt. pl) go to 80 >*/
    if (pu < pl) {
        goto L80;
    }
/*<       do 70 j = pl, pu >*/
    i__1 = pu;
    for (j = pl; j <= i__1; ++j) {
/*<          qraux(j) = dcmplx(dznrm2(n,x(1,j),1),0.0d0) >*/
        i__2 = j;
        d__1 = dznrm2_(n, &x[j * x_dim1 + 1], &c__1);
        z__1.r = d__1, z__1.i = 0.;
        qraux[i__2].r = z__1.r, qraux[i__2].i = z__1.i;
/*<          work(j) = qraux(j) >*/
        i__2 = j;
        i__3 = j;
        work[i__2].r = qraux[i__3].r, work[i__2].i = qraux[i__3].i;
/*<    70 continue >*/
/* L70: */
    }
/*<    80 continue >*/
L80:

/*     perform the householder reduction of x. */

/*<       lup = min0(n,p) >*/
    lup = min(*n,*p);
/*<       do 200 l = 1, lup >*/
    i__1 = lup;
    for (l = 1; l <= i__1; ++l) {
/*<          if (l .lt. pl .or. l .ge. pu) go to 120 >*/
        if (l < pl || l >= pu) {
            goto L120;
        }

/*           locate the column of largest norm and bring it */
/*           into the pivot position. */

/*<             maxnrm = 0.0d0 >*/
        maxnrm = 0.;
/*<             maxj = l >*/
        maxj = l;
/*<             do 100 j = l, pu >*/
        i__2 = pu;
        for (j = l; j <= i__2; ++j) {
/*<                if (dreal(qraux(j)) .le. maxnrm) go to 90 >*/
            i__3 = j;
            if (qraux[i__3].r <= maxnrm) {
                goto L90;
            }
/*<                   maxnrm = dreal(qraux(j)) >*/
            i__3 = j;
            maxnrm = qraux[i__3].r;
/*<                   maxj = j >*/
            maxj = j;
/*<    90          continue >*/
L90:
/*<   100       continue >*/
/* L100: */
            ;
        }
/*<             if (maxj .eq. l) go to 110 >*/
        if (maxj == l) {
            goto L110;
        }
/*<                call zswap(n,x(1,l),1,x(1,maxj),1) >*/
        zswap_(n, &x[l * x_dim1 + 1], &c__1, &x[maxj * x_dim1 + 1], &c__1);
/*<                qraux(maxj) = qraux(l) >*/
        i__2 = maxj;
        i__3 = l;
        qraux[i__2].r = qraux[i__3].r, qraux[i__2].i = qraux[i__3].i;
/*<                work(maxj) = work(l) >*/
        i__2 = maxj;
        i__3 = l;
        work[i__2].r = work[i__3].r, work[i__2].i = work[i__3].i;
/*<                jp = jpvt(maxj) >*/
        jp = jpvt[maxj];
/*<                jpvt(maxj) = jpvt(l) >*/
        jpvt[maxj] = jpvt[l];
/*<                jpvt(l) = jp >*/
        jpvt[l] = jp;
/*<   110       continue >*/
L110:
/*<   120    continue >*/
L120:
/*<          qraux(l) = (0.0d0,0.0d0) >*/
        i__2 = l;
        qraux[i__2].r = 0., qraux[i__2].i = 0.;
/*<          if (l .eq. n) go to 190 >*/
        if (l == *n) {
            goto L190;
        }

/*           compute the householder transformation for column l. */

/*<             nrmxl = dcmplx(dznrm2(n-l+1,x(l,l),1),0.0d0) >*/
        i__2 = *n - l + 1;
        d__1 = dznrm2_(&i__2, &x[l + l * x_dim1], &c__1);
        z__1.r = d__1, z__1.i = 0.;
        nrmxl.r = z__1.r, nrmxl.i = z__1.i;
/*<             if (cabs1(nrmxl) .eq. 0.0d0) go to 180 >*/
        z__1.r = nrmxl.r * 0. - nrmxl.i * -1., z__1.i = nrmxl.i * 0. + 
                nrmxl.r * -1.;
        if ((d__1 = nrmxl.r, abs(d__1)) + (d__2 = z__1.r, abs(d__2)) == 0.) {
            goto L180;
        }
/*<    >*/
        i__2 = l + l * x_dim1;
        i__3 = l + l * x_dim1;
        z__1.r = x[i__3].r * 0. - x[i__3].i * -1., z__1.i = x[i__3].i * 0. + 
                x[i__3].r * -1.;
        if ((d__1 = x[i__2].r, abs(d__1)) + (d__2 = z__1.r, abs(d__2)) != 0.) 
                {
            d__3 = z_abs(&nrmxl);
            i__4 = l + l * x_dim1;
            d__4 = z_abs(&x[l + l * x_dim1]);
            z__3.r = x[i__4].r / d__4, z__3.i = x[i__4].i / d__4;
            z__2.r = d__3 * z__3.r, z__2.i = d__3 * z__3.i;
            nrmxl.r = z__2.r, nrmxl.i = z__2.i;
        }
/*<                call zscal(n-l+1,(1.0d0,0.0d0)/nrmxl,x(l,l),1) >*/
        i__2 = *n - l + 1;
        z_div(&z__1, &c_b28, &nrmxl);
        zscal_(&i__2, &z__1, &x[l + l * x_dim1], &c__1);
/*<                x(l,l) = (1.0d0,0.0d0) + x(l,l) >*/
        i__2 = l + l * x_dim1;
        i__3 = l + l * x_dim1;
        z__1.r = x[i__3].r + 1., z__1.i = x[i__3].i + 0.;
        x[i__2].r = z__1.r, x[i__2].i = z__1.i;

/*              apply the transformation to the remaining columns, */
/*              updating the norms. */

/*<                lp1 = l + 1 >*/
        lp1 = l + 1;
/*<                if (p .lt. lp1) go to 170 >*/
        if (*p < lp1) {
            goto L170;
        }
/*<                do 160 j = lp1, p >*/
        i__2 = *p;
        for (j = lp1; j <= i__2; ++j) {
/*<                   t = -zdotc(n-l+1,x(l,l),1,x(l,j),1)/x(l,l) >*/
            i__3 = *n - l + 1;
            zdotc_(&z__3, &i__3, &x[l + l * x_dim1], &c__1, &x[l + j * x_dim1]
                    , &c__1);
            z__2.r = -z__3.r, z__2.i = -z__3.i;
            z_div(&z__1, &z__2, &x[l + l * x_dim1]);
            t.r = z__1.r, t.i = z__1.i;
/*<                   call zaxpy(n-l+1,t,x(l,l),1,x(l,j),1) >*/
            i__3 = *n - l + 1;
            zaxpy_(&i__3, &t, &x[l + l * x_dim1], &c__1, &x[l + j * x_dim1], &
                    c__1);
/*<                   if (j .lt. pl .or. j .gt. pu) go to 150 >*/
            if (j < pl || j > pu) {
                goto L150;
            }
/*<                   if (cabs1(qraux(j)) .eq. 0.0d0) go to 150 >*/
            i__3 = j;
            i__4 = j;
            z__1.r = qraux[i__4].r * 0. - qraux[i__4].i * -1., z__1.i = qraux[
                    i__4].i * 0. + qraux[i__4].r * -1.;
            if ((d__1 = qraux[i__3].r, abs(d__1)) + (d__2 = z__1.r, abs(d__2))
                     == 0.) {
                goto L150;
            }
/*<                      tt = 1.0d0 - (cdabs(x(l,j))/dreal(qraux(j)))**2 >*/
            i__3 = j;
/* Computing 2nd power */
            d__1 = z_abs(&x[l + j * x_dim1]) / qraux[i__3].r;
            tt = 1. - d__1 * d__1;
/*<                      tt = dmax1(tt,0.0d0) >*/
            tt = max(tt,0.);
/*<                      t = dcmplx(tt,0.0d0) >*/
            z__1.r = tt, z__1.i = 0.;
            t.r = z__1.r, t.i = z__1.i;
/*<    >*/
            i__3 = j;
            i__4 = j;
/* Computing 2nd power */
            d__1 = qraux[i__3].r / work[i__4].r;
            tt = tt * .05 * (d__1 * d__1) + 1.;
/*<                      if (tt .eq. 1.0d0) go to 130 >*/
            if (tt == 1.) {
                goto L130;
            }
/*<                         qraux(j) = qraux(j)*cdsqrt(t) >*/
            i__3 = j;
            i__4 = j;
            z_sqrt(&z__2, &t);
            z__1.r = qraux[i__4].r * z__2.r - qraux[i__4].i * z__2.i, z__1.i =
                     qraux[i__4].r * z__2.i + qraux[i__4].i * z__2.r;
            qraux[i__3].r = z__1.r, qraux[i__3].i = z__1.i;
/*<                      go to 140 >*/
            goto L140;
/*<   130                continue >*/
L130:
/*<                         qraux(j) = dcmplx(dznrm2(n-l,x(l+1,j),1),0.0d0) >*/
            i__3 = j;
            i__4 = *n - l;
            d__1 = dznrm2_(&i__4, &x[l + 1 + j * x_dim1], &c__1);
            z__1.r = d__1, z__1.i = 0.;
            qraux[i__3].r = z__1.r, qraux[i__3].i = z__1.i;
/*<                         work(j) = qraux(j) >*/
            i__3 = j;
            i__4 = j;
            work[i__3].r = qraux[i__4].r, work[i__3].i = qraux[i__4].i;
/*<   140                continue >*/
L140:
/*<   150             continue >*/
L150:
/*<   160          continue >*/
/* L160: */
            ;
        }
/*<   170          continue >*/
L170:

/*              save the transformation. */

/*<                qraux(l) = x(l,l) >*/
        i__2 = l;
        i__3 = l + l * x_dim1;
        qraux[i__2].r = x[i__3].r, qraux[i__2].i = x[i__3].i;
/*<                x(l,l) = -nrmxl >*/
        i__2 = l + l * x_dim1;
        z__1.r = -nrmxl.r, z__1.i = -nrmxl.i;
        x[i__2].r = z__1.r, x[i__2].i = z__1.i;
/*<   180       continue >*/
L180:
/*<   190    continue >*/
L190:
/*<   200 continue >*/
/* L200: */
        ;
    }
/*<       return >*/
    return 0;
/*<       end >*/
} /* zqrdc_ */

#ifdef __cplusplus
        }
#endif