sstebz.c

来自「NIST Handwriting OCR Testbed」· C语言 代码 · 共 766 行 · 第 1/2 页

	i__1 = *n - 1;
	for (j = 1; j <= *n-1; ++j) {
	    tmp2 = sqrt(WORK(j));
/* Computing MAX */
	    r__1 = gu, r__2 = D(j) + tmp1 + tmp2;
	    gu = dmax(r__1,r__2);
/* Computing MIN */
	    r__1 = gl, r__2 = D(j) - tmp1 - tmp2;
	    gl = dmin(r__1,r__2);
	    tmp1 = tmp2;
/* L20: */
	}

/* Computing MAX */
	r__1 = gu, r__2 = D(*n) + tmp1;
	gu = dmax(r__1,r__2);
/* Computing MIN */
	r__1 = gl, r__2 = D(*n) - tmp1;
	gl = dmin(r__1,r__2);
/* Computing MAX */
	r__1 = dabs(gl), r__2 = dabs(gu);
	tnorm = dmax(r__1,r__2);
	gl = gl - tnorm * 2.f * ulp * *n - pivmin * 4.f;
	gu = gu + tnorm * 2.f * ulp * *n + pivmin * 2.f;

/*        Compute Iteration parameters */

	itmax = (integer) ((log(tnorm + pivmin) - log(pivmin)) / log(2.f)) + 
		2;
	if (*abstol <= 0.f) {
	    atoli = ulp * tnorm;
	} else {
	    atoli = *abstol;
	}

	WORK(*n + 1) = gl;
	WORK(*n + 2) = gl;
	WORK(*n + 3) = gu;
	WORK(*n + 4) = gu;
	WORK(*n + 5) = gl;
	WORK(*n + 6) = gu;
	IWORK(1) = -1;
	IWORK(2) = -1;
	IWORK(3) = *n + 1;
	IWORK(4) = *n + 1;
	IWORK(5) = *il - 1;
	IWORK(6) = *iu;

	slaebz_(&c__3, &itmax, n, &c__2, &c__2, &nb, &atoli, &rtoli, &pivmin, 
		&D(1), &E(1), &WORK(1), &IWORK(5), &WORK(*n + 1), &WORK(*n + 
		5), &iout, &IWORK(1), &W(1), &IBLOCK(1), &iinfo);

	if (IWORK(6) == *iu) {
	    wl = WORK(*n + 1);
	    wlu = WORK(*n + 3);
	    nwl = IWORK(1);
	    wu = WORK(*n + 4);
	    wul = WORK(*n + 2);
	    nwu = IWORK(4);
	} else {
	    wl = WORK(*n + 2);
	    wlu = WORK(*n + 4);
	    nwl = IWORK(2);
	    wu = WORK(*n + 3);
	    wul = WORK(*n + 1);
	    nwu = IWORK(3);
	}

	if (nwl < 0 || nwl >= *n || nwu < 1 || nwu > *n) {
	    *info = 4;
	    return 0;
	}
    } else {

/*        RANGE='A' or 'V' -- Set ATOLI   

   Computing MAX */
	r__3 = dabs(D(1)) + dabs(E(1)), r__4 = (r__1 = D(*n), dabs(r__1)) + (
		r__2 = E(*n - 1), dabs(r__2));
	tnorm = dmax(r__3,r__4);

	i__1 = *n - 1;
	for (j = 2; j <= *n-1; ++j) {
/* Computing MAX */
	    r__4 = tnorm, r__5 = (r__1 = D(j), dabs(r__1)) + (r__2 = E(j - 1),
		     dabs(r__2)) + (r__3 = E(j), dabs(r__3));
	    tnorm = dmax(r__4,r__5);
/* L30: */
	}

	if (*abstol <= 0.f) {
	    atoli = ulp * tnorm;
	} else {
	    atoli = *abstol;
	}

	if (irange == 2) {
	    wl = *vl;
	    wu = *vu;
	}
    }

/*     Find Eigenvalues -- Loop Over Blocks and recompute NWL and NWU.   
       NWL accumulates the number of eigenvalues .le. WL,   
       NWU accumulates the number of eigenvalues .le. WU */

    *m = 0;
    iend = 0;
    *info = 0;
    nwl = 0;
    nwu = 0;

    i__1 = *nsplit;
    for (jb = 1; jb <= *nsplit; ++jb) {
	ioff = iend;
	ibegin = ioff + 1;
	iend = ISPLIT(jb);
	in = iend - ioff;

	if (in == 1) {

/*           Special Case -- IN=1 */

	    if (irange == 1 || wl >= D(ibegin) - pivmin) {
		++nwl;
	    }
	    if (irange == 1 || wu >= D(ibegin) - pivmin) {
		++nwu;
	    }
	    if (irange == 1 || wl < D(ibegin) - pivmin && wu >= D(ibegin) - 
		    pivmin) {
		++(*m);
		W(*m) = D(ibegin);
		IBLOCK(*m) = jb;
	    }
	} else {

/*           General Case -- IN > 1   

             Compute Gershgorin Interval   
             and use it as the initial interval */

	    gu = D(ibegin);
	    gl = D(ibegin);
	    tmp1 = 0.f;

	    i__2 = iend - 1;
	    for (j = ibegin; j <= iend-1; ++j) {
		tmp2 = (r__1 = E(j), dabs(r__1));
/* Computing MAX */
		r__1 = gu, r__2 = D(j) + tmp1 + tmp2;
		gu = dmax(r__1,r__2);
/* Computing MIN */
		r__1 = gl, r__2 = D(j) - tmp1 - tmp2;
		gl = dmin(r__1,r__2);
		tmp1 = tmp2;
/* L40: */
	    }

/* Computing MAX */
	    r__1 = gu, r__2 = D(iend) + tmp1;
	    gu = dmax(r__1,r__2);
/* Computing MIN */
	    r__1 = gl, r__2 = D(iend) - tmp1;
	    gl = dmin(r__1,r__2);
/* Computing MAX */
	    r__1 = dabs(gl), r__2 = dabs(gu);
	    bnorm = dmax(r__1,r__2);
	    gl = gl - bnorm * 2.f * ulp * in - pivmin * 2.f;
	    gu = gu + bnorm * 2.f * ulp * in + pivmin * 2.f;

/*           Compute ATOLI for the current submatrix */

	    if (*abstol <= 0.f) {
/* Computing MAX */
		r__1 = dabs(gl), r__2 = dabs(gu);
		atoli = ulp * dmax(r__1,r__2);
	    } else {
		atoli = *abstol;
	    }

	    if (irange > 1) {
		if (gu < wl) {
		    nwl += in;
		    nwu += in;
		    goto L70;
		}
		gl = dmax(gl,wl);
		gu = dmin(gu,wu);
		if (gl >= gu) {
		    goto L70;
		}
	    }

/*           Set Up Initial Interval */

	    WORK(*n + 1) = gl;
	    WORK(*n + in + 1) = gu;
	    slaebz_(&c__1, &c__0, &in, &in, &c__1, &nb, &atoli, &rtoli, &
		    pivmin, &D(ibegin), &E(ibegin), &WORK(ibegin), idumma, &
		    WORK(*n + 1), &WORK(*n + (in << 1) + 1), &im, &IWORK(1), &
		    W(*m + 1), &IBLOCK(*m + 1), &iinfo);

	    nwl += IWORK(1);
	    nwu += IWORK(in + 1);
	    iwoff = *m - IWORK(1);

/*           Compute Eigenvalues */

	    itmax = (integer) ((log(gu - gl + pivmin) - log(pivmin)) / log(
		    2.f)) + 2;
	    slaebz_(&c__2, &itmax, &in, &in, &c__1, &nb, &atoli, &rtoli, &
		    pivmin, &D(ibegin), &E(ibegin), &WORK(ibegin), idumma, &
		    WORK(*n + 1), &WORK(*n + (in << 1) + 1), &iout, &IWORK(1),
		     &W(*m + 1), &IBLOCK(*m + 1), &iinfo);

/*           Copy Eigenvalues Into W and IBLOCK   
             Use -JB for block number for unconverged eigenvalues.
 */

	    i__2 = iout;
	    for (j = 1; j <= iout; ++j) {
		tmp1 = (WORK(j + *n) + WORK(j + in + *n)) * .5f;

/*              Flag non-convergence. */

		if (j > iout - iinfo) {
		    ncnvrg = TRUE_;
		    ib = -jb;
		} else {
		    ib = jb;
		}
		i__3 = IWORK(j + in) + iwoff;
		for (je = IWORK(j) + 1 + iwoff; je <= IWORK(j+in)+iwoff; ++je) {
		    W(je) = tmp1;
		    IBLOCK(je) = ib;
/* L50: */
		}
/* L60: */
	    }

	    *m += im;
	}
L70:
	;
    }

/*     If RANGE='I', then (WL,WU) contains eigenvalues NWL+1,...,NWU   
       If NWL+1 < IL or NWU > IU, discard extra eigenvalues. */

    if (irange == 3) {
	im = 0;
	idiscl = *il - 1 - nwl;
	idiscu = nwu - *iu;

	if (idiscl > 0 || idiscu > 0) {
	    i__1 = *m;
	    for (je = 1; je <= *m; ++je) {
		if (W(je) <= wlu && idiscl > 0) {
		    --idiscl;
		} else if (W(je) >= wul && idiscu > 0) {
		    --idiscu;
		} else {
		    ++im;
		    W(im) = W(je);
		    IBLOCK(im) = IBLOCK(je);
		}
/* L80: */
	    }
	    *m = im;
	}
	if (idiscl > 0 || idiscu > 0) {

/*           Code to deal with effects of bad arithmetic:   
             Some low eigenvalues to be discarded are not in (WL,W
LU],   
             or high eigenvalues to be discarded are not in (WUL,W
U]   
             so just kill off the smallest IDISCL/largest IDISCU 
  
             eigenvalues, by simply finding the smallest/largest 
  
             eigenvalue(s).   

             (If N(w) is monotone non-decreasing, this should neve
r   
                 happen.) */

	    if (idiscl > 0) {
		wkill = wu;
		i__1 = idiscl;
		for (jdisc = 1; jdisc <= idiscl; ++jdisc) {
		    iw = 0;
		    i__2 = *m;
		    for (je = 1; je <= *m; ++je) {
			if (IBLOCK(je) != 0 && (W(je) < wkill || iw == 0)) {
			    iw = je;
			    wkill = W(je);
			}
/* L90: */
		    }
		    IBLOCK(iw) = 0;
/* L100: */
		}
	    }
	    if (idiscu > 0) {

		wkill = wl;
		i__1 = idiscu;
		for (jdisc = 1; jdisc <= idiscu; ++jdisc) {
		    iw = 0;
		    i__2 = *m;
		    for (je = 1; je <= *m; ++je) {
			if (IBLOCK(je) != 0 && (W(je) > wkill || iw == 0)) {
			    iw = je;
			    wkill = W(je);
			}
/* L110: */
		    }
		    IBLOCK(iw) = 0;
/* L120: */
		}
	    }
	    im = 0;
	    i__1 = *m;
	    for (je = 1; je <= *m; ++je) {
		if (IBLOCK(je) != 0) {
		    ++im;
		    W(im) = W(je);
		    IBLOCK(im) = IBLOCK(je);
		}
/* L130: */
	    }
	    *m = im;
	}
	if (idiscl < 0 || idiscu < 0) {
	    toofew = TRUE_;
	}
    }

/*     If ORDER='B', do nothing -- the eigenvalues are already sorted   
          by block.   
       If ORDER='E', sort the eigenvalues from smallest to largest */

    if (iorder == 1 && *nsplit > 1) {
	i__1 = *m - 1;
	for (je = 1; je <= *m-1; ++je) {
	    ie = 0;
	    tmp1 = W(je);
	    i__2 = *m;
	    for (j = je + 1; j <= *m; ++j) {
		if (W(j) < tmp1) {
		    ie = j;
		    tmp1 = W(j);
		}
/* L140: */
	    }

	    if (ie != 0) {
		itmp1 = IBLOCK(ie);
		W(ie) = W(je);
		IBLOCK(ie) = IBLOCK(je);
		W(je) = tmp1;
		IBLOCK(je) = itmp1;
	    }
/* L150: */
	}
    }

    *info = 0;
    if (ncnvrg) {
	++(*info);
    }
    if (toofew) {
	*info += 2;
    }
    return 0;

/*     End of SSTEBZ */

} /* sstebz_ */