--- /dev/null
+#include "clapack.h"
+
+/* Table of constant values */
+
+static integer c__1 = 1;
+static integer c__2 = 2;
+static integer c__10 = 10;
+static integer c__3 = 3;
+static integer c__4 = 4;
+static integer c__11 = 11;
+
+/* Subroutine */ int dlasq2_(integer *n, doublereal *z__, integer *info)
+{
+ /* System generated locals */
+ integer i__1, i__2, i__3;
+ doublereal d__1, d__2;
+
+ /* Builtin functions */
+ double sqrt(doublereal);
+
+ /* Local variables */
+ doublereal d__, e;
+ integer k;
+ doublereal s, t;
+ integer i0, i4, n0;
+ doublereal dn;
+ integer pp;
+ doublereal dn1, dn2, eps, tau, tol;
+ integer ipn4;
+ doublereal tol2;
+ logical ieee;
+ integer nbig;
+ doublereal dmin__, emin, emax;
+ integer ndiv, iter;
+ doublereal qmin, temp, qmax, zmax;
+ integer splt;
+ doublereal dmin1, dmin2;
+ integer nfail;
+ doublereal desig, trace, sigma;
+ integer iinfo, ttype;
+ extern /* Subroutine */ int dlazq3_(integer *, integer *, doublereal *,
+ integer *, doublereal *, doublereal *, doublereal *, doublereal *,
+ integer *, integer *, integer *, logical *, integer *,
+ doublereal *, doublereal *, doublereal *, doublereal *,
+ doublereal *, doublereal *);
+ extern doublereal dlamch_(char *);
+ integer iwhila, iwhilb;
+ doublereal oldemn, safmin;
+ extern /* Subroutine */ int xerbla_(char *, integer *);
+ extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
+ integer *, integer *);
+ extern /* Subroutine */ int dlasrt_(char *, integer *, doublereal *,
+ integer *);
+
+
+/* -- LAPACK routine (version 3.1) -- */
+/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
+/* November 2006 */
+
+/* Modified to call DLAZQ3 in place of DLASQ3, 13 Feb 03, SJH. */
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* DLASQ2 computes all the eigenvalues of the symmetric positive */
+/* definite tridiagonal matrix associated with the qd array Z to high */
+/* relative accuracy are computed to high relative accuracy, in the */
+/* absence of denormalization, underflow and overflow. */
+
+/* To see the relation of Z to the tridiagonal matrix, let L be a */
+/* unit lower bidiagonal matrix with subdiagonals Z(2,4,6,,..) and */
+/* let U be an upper bidiagonal matrix with 1's above and diagonal */
+/* Z(1,3,5,,..). The tridiagonal is L*U or, if you prefer, the */
+/* symmetric tridiagonal to which it is similar. */
+
+/* Note : DLASQ2 defines a logical variable, IEEE, which is true */
+/* on machines which follow ieee-754 floating-point standard in their */
+/* handling of infinities and NaNs, and false otherwise. This variable */
+/* is passed to DLAZQ3. */
+
+/* Arguments */
+/* ========= */
+
+/* N (input) INTEGER */
+/* The number of rows and columns in the matrix. N >= 0. */
+
+/* Z (workspace) DOUBLE PRECISION array, dimension ( 4*N ) */
+/* On entry Z holds the qd array. On exit, entries 1 to N hold */
+/* the eigenvalues in decreasing order, Z( 2*N+1 ) holds the */
+/* trace, and Z( 2*N+2 ) holds the sum of the eigenvalues. If */
+/* N > 2, then Z( 2*N+3 ) holds the iteration count, Z( 2*N+4 ) */
+/* holds NDIVS/NIN^2, and Z( 2*N+5 ) holds the percentage of */
+/* shifts that failed. */
+
+/* INFO (output) INTEGER */
+/* = 0: successful exit */
+/* < 0: if the i-th argument is a scalar and had an illegal */
+/* value, then INFO = -i, if the i-th argument is an */
+/* array and the j-entry had an illegal value, then */
+/* INFO = -(i*100+j) */
+/* > 0: the algorithm failed */
+/* = 1, a split was marked by a positive value in E */
+/* = 2, current block of Z not diagonalized after 30*N */
+/* iterations (in inner while loop) */
+/* = 3, termination criterion of outer while loop not met */
+/* (program created more than N unreduced blocks) */
+
+/* Further Details */
+/* =============== */
+/* Local Variables: I0:N0 defines a current unreduced segment of Z. */
+/* The shifts are accumulated in SIGMA. Iteration count is in ITER. */
+/* Ping-pong is controlled by PP (alternates between 0 and 1). */
+
+/* ===================================================================== */
+
+/* .. Parameters .. */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. External Subroutines .. */
+/* .. */
+/* .. External Functions .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+/* .. Executable Statements .. */
+
+/* Test the input arguments. */
+/* (in case DLASQ2 is not called by DLASQ1) */
+
+ /* Parameter adjustments */
+ --z__;
+
+ /* Function Body */
+ *info = 0;
+ eps = dlamch_("Precision");
+ safmin = dlamch_("Safe minimum");
+ tol = eps * 100.;
+/* Computing 2nd power */
+ d__1 = tol;
+ tol2 = d__1 * d__1;
+
+ if (*n < 0) {
+ *info = -1;
+ xerbla_("DLASQ2", &c__1);
+ return 0;
+ } else if (*n == 0) {
+ return 0;
+ } else if (*n == 1) {
+
+/* 1-by-1 case. */
+
+ if (z__[1] < 0.) {
+ *info = -201;
+ xerbla_("DLASQ2", &c__2);
+ }
+ return 0;
+ } else if (*n == 2) {
+
+/* 2-by-2 case. */
+
+ if (z__[2] < 0. || z__[3] < 0.) {
+ *info = -2;
+ xerbla_("DLASQ2", &c__2);
+ return 0;
+ } else if (z__[3] > z__[1]) {
+ d__ = z__[3];
+ z__[3] = z__[1];
+ z__[1] = d__;
+ }
+ z__[5] = z__[1] + z__[2] + z__[3];
+ if (z__[2] > z__[3] * tol2) {
+ t = (z__[1] - z__[3] + z__[2]) * .5;
+ s = z__[3] * (z__[2] / t);
+ if (s <= t) {
+ s = z__[3] * (z__[2] / (t * (sqrt(s / t + 1.) + 1.)));
+ } else {
+ s = z__[3] * (z__[2] / (t + sqrt(t) * sqrt(t + s)));
+ }
+ t = z__[1] + (s + z__[2]);
+ z__[3] *= z__[1] / t;
+ z__[1] = t;
+ }
+ z__[2] = z__[3];
+ z__[6] = z__[2] + z__[1];
+ return 0;
+ }
+
+/* Check for negative data and compute sums of q's and e's. */
+
+ z__[*n * 2] = 0.;
+ emin = z__[2];
+ qmax = 0.;
+ zmax = 0.;
+ d__ = 0.;
+ e = 0.;
+
+ i__1 = *n - 1 << 1;
+ for (k = 1; k <= i__1; k += 2) {
+ if (z__[k] < 0.) {
+ *info = -(k + 200);
+ xerbla_("DLASQ2", &c__2);
+ return 0;
+ } else if (z__[k + 1] < 0.) {
+ *info = -(k + 201);
+ xerbla_("DLASQ2", &c__2);
+ return 0;
+ }
+ d__ += z__[k];
+ e += z__[k + 1];
+/* Computing MAX */
+ d__1 = qmax, d__2 = z__[k];
+ qmax = max(d__1,d__2);
+/* Computing MIN */
+ d__1 = emin, d__2 = z__[k + 1];
+ emin = min(d__1,d__2);
+/* Computing MAX */
+ d__1 = max(qmax,zmax), d__2 = z__[k + 1];
+ zmax = max(d__1,d__2);
+/* L10: */
+ }
+ if (z__[(*n << 1) - 1] < 0.) {
+ *info = -((*n << 1) + 199);
+ xerbla_("DLASQ2", &c__2);
+ return 0;
+ }
+ d__ += z__[(*n << 1) - 1];
+/* Computing MAX */
+ d__1 = qmax, d__2 = z__[(*n << 1) - 1];
+ qmax = max(d__1,d__2);
+ zmax = max(qmax,zmax);
+
+/* Check for diagonality. */
+
+ if (e == 0.) {
+ i__1 = *n;
+ for (k = 2; k <= i__1; ++k) {
+ z__[k] = z__[(k << 1) - 1];
+/* L20: */
+ }
+ dlasrt_("D", n, &z__[1], &iinfo);
+ z__[(*n << 1) - 1] = d__;
+ return 0;
+ }
+
+ trace = d__ + e;
+
+/* Check for zero data. */
+
+ if (trace == 0.) {
+ z__[(*n << 1) - 1] = 0.;
+ return 0;
+ }
+
+/* Check whether the machine is IEEE conformable. */
+
+ ieee = ilaenv_(&c__10, "DLASQ2", "N", &c__1, &c__2, &c__3, &c__4) == 1 && ilaenv_(&c__11, "DLASQ2", "N", &c__1, &c__2,
+ &c__3, &c__4) == 1;
+
+/* Rearrange data for locality: Z=(q1,qq1,e1,ee1,q2,qq2,e2,ee2,...). */
+
+ for (k = *n << 1; k >= 2; k += -2) {
+ z__[k * 2] = 0.;
+ z__[(k << 1) - 1] = z__[k];
+ z__[(k << 1) - 2] = 0.;
+ z__[(k << 1) - 3] = z__[k - 1];
+/* L30: */
+ }
+
+ i0 = 1;
+ n0 = *n;
+
+/* Reverse the qd-array, if warranted. */
+
+ if (z__[(i0 << 2) - 3] * 1.5 < z__[(n0 << 2) - 3]) {
+ ipn4 = i0 + n0 << 2;
+ i__1 = i0 + n0 - 1 << 1;
+ for (i4 = i0 << 2; i4 <= i__1; i4 += 4) {
+ temp = z__[i4 - 3];
+ z__[i4 - 3] = z__[ipn4 - i4 - 3];
+ z__[ipn4 - i4 - 3] = temp;
+ temp = z__[i4 - 1];
+ z__[i4 - 1] = z__[ipn4 - i4 - 5];
+ z__[ipn4 - i4 - 5] = temp;
+/* L40: */
+ }
+ }
+
+/* Initial split checking via dqd and Li's test. */
+
+ pp = 0;
+
+ for (k = 1; k <= 2; ++k) {
+
+ d__ = z__[(n0 << 2) + pp - 3];
+ i__1 = (i0 << 2) + pp;
+ for (i4 = (n0 - 1 << 2) + pp; i4 >= i__1; i4 += -4) {
+ if (z__[i4 - 1] <= tol2 * d__) {
+ z__[i4 - 1] = -0.;
+ d__ = z__[i4 - 3];
+ } else {
+ d__ = z__[i4 - 3] * (d__ / (d__ + z__[i4 - 1]));
+ }
+/* L50: */
+ }
+
+/* dqd maps Z to ZZ plus Li's test. */
+
+ emin = z__[(i0 << 2) + pp + 1];
+ d__ = z__[(i0 << 2) + pp - 3];
+ i__1 = (n0 - 1 << 2) + pp;
+ for (i4 = (i0 << 2) + pp; i4 <= i__1; i4 += 4) {
+ z__[i4 - (pp << 1) - 2] = d__ + z__[i4 - 1];
+ if (z__[i4 - 1] <= tol2 * d__) {
+ z__[i4 - 1] = -0.;
+ z__[i4 - (pp << 1) - 2] = d__;
+ z__[i4 - (pp << 1)] = 0.;
+ d__ = z__[i4 + 1];
+ } else if (safmin * z__[i4 + 1] < z__[i4 - (pp << 1) - 2] &&
+ safmin * z__[i4 - (pp << 1) - 2] < z__[i4 + 1]) {
+ temp = z__[i4 + 1] / z__[i4 - (pp << 1) - 2];
+ z__[i4 - (pp << 1)] = z__[i4 - 1] * temp;
+ d__ *= temp;
+ } else {
+ z__[i4 - (pp << 1)] = z__[i4 + 1] * (z__[i4 - 1] / z__[i4 - (
+ pp << 1) - 2]);
+ d__ = z__[i4 + 1] * (d__ / z__[i4 - (pp << 1) - 2]);
+ }
+/* Computing MIN */
+ d__1 = emin, d__2 = z__[i4 - (pp << 1)];
+ emin = min(d__1,d__2);
+/* L60: */
+ }
+ z__[(n0 << 2) - pp - 2] = d__;
+
+/* Now find qmax. */
+
+ qmax = z__[(i0 << 2) - pp - 2];
+ i__1 = (n0 << 2) - pp - 2;
+ for (i4 = (i0 << 2) - pp + 2; i4 <= i__1; i4 += 4) {
+/* Computing MAX */
+ d__1 = qmax, d__2 = z__[i4];
+ qmax = max(d__1,d__2);
+/* L70: */
+ }
+
+/* Prepare for the next iteration on K. */
+
+ pp = 1 - pp;
+/* L80: */
+ }
+
+/* Initialise variables to pass to DLAZQ3 */
+
+ ttype = 0;
+ dmin1 = 0.;
+ dmin2 = 0.;
+ dn = 0.;
+ dn1 = 0.;
+ dn2 = 0.;
+ tau = 0.;
+
+ iter = 2;
+ nfail = 0;
+ ndiv = n0 - i0 << 1;
+
+ i__1 = *n + 1;
+ for (iwhila = 1; iwhila <= i__1; ++iwhila) {
+ if (n0 < 1) {
+ goto L150;
+ }
+
+/* While array unfinished do */
+
+/* E(N0) holds the value of SIGMA when submatrix in I0:N0 */
+/* splits from the rest of the array, but is negated. */
+
+ desig = 0.;
+ if (n0 == *n) {
+ sigma = 0.;
+ } else {
+ sigma = -z__[(n0 << 2) - 1];
+ }
+ if (sigma < 0.) {
+ *info = 1;
+ return 0;
+ }
+
+/* Find last unreduced submatrix's top index I0, find QMAX and */
+/* EMIN. Find Gershgorin-type bound if Q's much greater than E's. */
+
+ emax = 0.;
+ if (n0 > i0) {
+ emin = (d__1 = z__[(n0 << 2) - 5], abs(d__1));
+ } else {
+ emin = 0.;
+ }
+ qmin = z__[(n0 << 2) - 3];
+ qmax = qmin;
+ for (i4 = n0 << 2; i4 >= 8; i4 += -4) {
+ if (z__[i4 - 5] <= 0.) {
+ goto L100;
+ }
+ if (qmin >= emax * 4.) {
+/* Computing MIN */
+ d__1 = qmin, d__2 = z__[i4 - 3];
+ qmin = min(d__1,d__2);
+/* Computing MAX */
+ d__1 = emax, d__2 = z__[i4 - 5];
+ emax = max(d__1,d__2);
+ }
+/* Computing MAX */
+ d__1 = qmax, d__2 = z__[i4 - 7] + z__[i4 - 5];
+ qmax = max(d__1,d__2);
+/* Computing MIN */
+ d__1 = emin, d__2 = z__[i4 - 5];
+ emin = min(d__1,d__2);
+/* L90: */
+ }
+ i4 = 4;
+
+L100:
+ i0 = i4 / 4;
+
+/* Store EMIN for passing to DLAZQ3. */
+
+ z__[(n0 << 2) - 1] = emin;
+
+/* Put -(initial shift) into DMIN. */
+
+/* Computing MAX */
+ d__1 = 0., d__2 = qmin - sqrt(qmin) * 2. * sqrt(emax);
+ dmin__ = -max(d__1,d__2);
+
+/* Now I0:N0 is unreduced. PP = 0 for ping, PP = 1 for pong. */
+
+ pp = 0;
+
+ nbig = (n0 - i0 + 1) * 30;
+ i__2 = nbig;
+ for (iwhilb = 1; iwhilb <= i__2; ++iwhilb) {
+ if (i0 > n0) {
+ goto L130;
+ }
+
+/* While submatrix unfinished take a good dqds step. */
+
+ dlazq3_(&i0, &n0, &z__[1], &pp, &dmin__, &sigma, &desig, &qmax, &
+ nfail, &iter, &ndiv, &ieee, &ttype, &dmin1, &dmin2, &dn, &
+ dn1, &dn2, &tau);
+
+ pp = 1 - pp;
+
+/* When EMIN is very small check for splits. */
+
+ if (pp == 0 && n0 - i0 >= 3) {
+ if (z__[n0 * 4] <= tol2 * qmax || z__[(n0 << 2) - 1] <= tol2 *
+ sigma) {
+ splt = i0 - 1;
+ qmax = z__[(i0 << 2) - 3];
+ emin = z__[(i0 << 2) - 1];
+ oldemn = z__[i0 * 4];
+ i__3 = n0 - 3 << 2;
+ for (i4 = i0 << 2; i4 <= i__3; i4 += 4) {
+ if (z__[i4] <= tol2 * z__[i4 - 3] || z__[i4 - 1] <=
+ tol2 * sigma) {
+ z__[i4 - 1] = -sigma;
+ splt = i4 / 4;
+ qmax = 0.;
+ emin = z__[i4 + 3];
+ oldemn = z__[i4 + 4];
+ } else {
+/* Computing MAX */
+ d__1 = qmax, d__2 = z__[i4 + 1];
+ qmax = max(d__1,d__2);
+/* Computing MIN */
+ d__1 = emin, d__2 = z__[i4 - 1];
+ emin = min(d__1,d__2);
+/* Computing MIN */
+ d__1 = oldemn, d__2 = z__[i4];
+ oldemn = min(d__1,d__2);
+ }
+/* L110: */
+ }
+ z__[(n0 << 2) - 1] = emin;
+ z__[n0 * 4] = oldemn;
+ i0 = splt + 1;
+ }
+ }
+
+/* L120: */
+ }
+
+ *info = 2;
+ return 0;
+
+/* end IWHILB */
+
+L130:
+
+/* L140: */
+ ;
+ }
+
+ *info = 3;
+ return 0;
+
+/* end IWHILA */
+
+L150:
+
+/* Move q's to the front. */
+
+ i__1 = *n;
+ for (k = 2; k <= i__1; ++k) {
+ z__[k] = z__[(k << 2) - 3];
+/* L160: */
+ }
+
+/* Sort and compute sum of eigenvalues. */
+
+ dlasrt_("D", n, &z__[1], &iinfo);
+
+ e = 0.;
+ for (k = *n; k >= 1; --k) {
+ e += z__[k];
+/* L170: */
+ }
+
+/* Store trace, sum(eigenvalues) and information on performance. */
+
+ z__[(*n << 1) + 1] = trace;
+ z__[(*n << 1) + 2] = e;
+ z__[(*n << 1) + 3] = (doublereal) iter;
+/* Computing 2nd power */
+ i__1 = *n;
+ z__[(*n << 1) + 4] = (doublereal) ndiv / (doublereal) (i__1 * i__1);
+ z__[(*n << 1) + 5] = nfail * 100. / (doublereal) iter;
+ return 0;
+
+/* End of DLASQ2 */
+
+} /* dlasq2_ */
projects / opencv / blobdiff