#include "blaswrap.h" /* -- translated by f2c (version 19990503). You must link the resulting object file with the libraries: -lf2c -lm (in that order) */ #include "f2c.h" /* Common Block Declarations */ struct { real ops, itcnt; } latime_; #define latime_1 latime_ /* Table of constant values */ static integer c__1 = 1; static real c_b22 = 1.f; static real c_b23 = 0.f; /* Subroutine */ int slaed3_(integer *k, integer *n, integer *n1, real *d__, real *q, integer *ldq, real *rho, real *dlamda, real *q2, integer * indx, integer *ctot, real *w, real *s, integer *info) { /* System generated locals */ integer q_dim1, q_offset, i__1, i__2; real r__1; /* Builtin functions */ double sqrt(doublereal), r_sign(real *, real *); /* Local variables */ static real temp; extern doublereal snrm2_(integer *, real *, integer *); static integer i__, j; extern /* Subroutine */ int sgemm_(char *, char *, integer *, integer *, integer *, real *, real *, integer *, real *, integer *, real *, real *, integer *), scopy_(integer *, real *, integer *, real *, integer *); static integer n2; extern /* Subroutine */ int slaed4_(integer *, integer *, real *, real *, real *, real *, real *, integer *); extern doublereal slamc3_(real *, real *); static integer n12, ii, n23; extern /* Subroutine */ int xerbla_(char *, integer *), slacpy_( char *, integer *, integer *, real *, integer *, real *, integer * ), slaset_(char *, integer *, integer *, real *, real *, real *, integer *); static integer iq2; #define q_ref(a_1,a_2) q[(a_2)*q_dim1 + a_1] /* -- LAPACK routine (instrumented to count operations, version 3.0) -- Univ. of Tennessee, Oak Ridge National Lab, Argonne National Lab, Courant Institute, NAG Ltd., and Rice University June 30, 1999 Common block to return operation count and iteration count ITCNT is unchanged, OPS is only incremented Purpose ======= SLAED3 finds the roots of the secular equation, as defined by the values in D, W, and RHO, between 1 and K. It makes the appropriate calls to SLAED4 and then updates the eigenvectors by multiplying the matrix of eigenvectors of the pair of eigensystems being combined by the matrix of eigenvectors of the K-by-K system which is solved here. This code makes very mild assumptions about floating point arithmetic. It will work on machines with a guard digit in add/subtract, or on those binary machines without guard digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or Cray-2. It could conceivably fail on hexadecimal or decimal machines without guard digits, but we know of none. Arguments ========= K (input) INTEGER The number of terms in the rational function to be solved by SLAED4. K >= 0. N (input) INTEGER The number of rows and columns in the Q matrix. N >= K (deflation may result in N>K). N1 (input) INTEGER The location of the last eigenvalue in the leading submatrix. min(1,N) <= N1 <= N/2. D (output) REAL array, dimension (N) D(I) contains the updated eigenvalues for 1 <= I <= K. Q (output) REAL array, dimension (LDQ,N) Initially the first K columns are used as workspace. On output the columns 1 to K contain the updated eigenvectors. LDQ (input) INTEGER The leading dimension of the array Q. LDQ >= max(1,N). RHO (input) REAL The value of the parameter in the rank one update equation. RHO >= 0 required. DLAMDA (input/output) REAL array, dimension (K) The first K elements of this array contain the old roots of the deflated updating problem. These are the poles of the secular equation. May be changed on output by having lowest order bit set to zero on Cray X-MP, Cray Y-MP, Cray-2, or Cray C-90, as described above. Q2 (input) REAL array, dimension (LDQ2, N) The first K columns of this matrix contain the non-deflated eigenvectors for the split problem. INDX (input) INTEGER array, dimension (N) The permutation used to arrange the columns of the deflated Q matrix into three groups (see SLAED2). The rows of the eigenvectors found by SLAED4 must be likewise permuted before the matrix multiply can take place. CTOT (input) INTEGER array, dimension (4) A count of the total number of the various types of columns in Q, as described in INDX. The fourth column type is any column which has been deflated. W (input/output) REAL array, dimension (K) The first K elements of this array contain the components of the deflation-adjusted updating vector. Destroyed on output. S (workspace) REAL array, dimension (N1 + 1)*K Will contain the eigenvectors of the repaired matrix which will be multiplied by the previously accumulated eigenvectors to update the system. LDS (input) INTEGER The leading dimension of S. LDS >= max(1,K). INFO (output) INTEGER = 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value. > 0: if INFO = 1, an eigenvalue did not converge Further Details =============== Based on contributions by Jeff Rutter, Computer Science Division, University of California at Berkeley, USA Modified by Francoise Tisseur, University of Tennessee. ===================================================================== Test the input parameters. Parameter adjustments */ --d__; q_dim1 = *ldq; q_offset = 1 + q_dim1 * 1; q -= q_offset; --dlamda; --q2; --indx; --ctot; --w; --s; /* Function Body */ *info = 0; if (*k < 0) { *info = -1; } else if (*n < *k) { *info = -2; } else if (*ldq < max(1,*n)) { *info = -6; } if (*info != 0) { i__1 = -(*info); xerbla_("SLAED3", &i__1); return 0; } /* Quick return if possible */ if (*k == 0) { return 0; } /* Modify values DLAMDA(i) to make sure all DLAMDA(i)-DLAMDA(j) can be computed with high relative accuracy (barring over/underflow). This is a problem on machines without a guard digit in add/subtract (Cray XMP, Cray YMP, Cray C 90 and Cray 2). The following code replaces DLAMDA(I) by 2*DLAMDA(I)-DLAMDA(I), which on any of these machines zeros out the bottommost bit of DLAMDA(I) if it is 1; this makes the subsequent subtractions DLAMDA(I)-DLAMDA(J) unproblematic when cancellation occurs. On binary machines with a guard digit (almost all machines) it does not change DLAMDA(I) at all. On hexadecimal and decimal machines with a guard digit, it slightly changes the bottommost bits of DLAMDA(I). It does not account for hexadecimal or decimal machines without guard digits (we know of none). We use a subroutine call to compute 2*DLAMBDA(I) to prevent optimizing compilers from eliminating this code. */ latime_1.ops += *n << 1; i__1 = *k; for (i__ = 1; i__ <= i__1; ++i__) { dlamda[i__] = slamc3_(&dlamda[i__], &dlamda[i__]) - dlamda[i__]; /* L10: */ } i__1 = *k; for (j = 1; j <= i__1; ++j) { slaed4_(k, &j, &dlamda[1], &w[1], &q_ref(1, j), rho, &d__[j], info); /* If the zero finder fails, the computation is terminated. */ if (*info != 0) { goto L120; } /* L20: */ } if (*k == 1) { goto L110; } if (*k == 2) { i__1 = *k; for (j = 1; j <= i__1; ++j) { w[1] = q_ref(1, j); w[2] = q_ref(2, j); ii = indx[1]; q_ref(1, j) = w[ii]; ii = indx[2]; q_ref(2, j) = w[ii]; /* L30: */ } goto L110; } /* Compute updated W. */ scopy_(k, &w[1], &c__1, &s[1], &c__1); /* Initialize W(I) = Q(I,I) */ i__1 = *ldq + 1; scopy_(k, &q[q_offset], &i__1, &w[1], &c__1); latime_1.ops += *k * 3 * (*k - 1); i__1 = *k; for (j = 1; j <= i__1; ++j) { i__2 = j - 1; for (i__ = 1; i__ <= i__2; ++i__) { w[i__] *= q_ref(i__, j) / (dlamda[i__] - dlamda[j]); /* L40: */ } i__2 = *k; for (i__ = j + 1; i__ <= i__2; ++i__) { w[i__] *= q_ref(i__, j) / (dlamda[i__] - dlamda[j]); /* L50: */ } /* L60: */ } latime_1.ops += *k; i__1 = *k; for (i__ = 1; i__ <= i__1; ++i__) { r__1 = sqrt(-w[i__]); w[i__] = r_sign(&r__1, &s[i__]); /* L70: */ } /* Compute eigenvectors of the modified rank-1 modification. */ latime_1.ops += (*k << 2) * *k; i__1 = *k; for (j = 1; j <= i__1; ++j) { i__2 = *k; for (i__ = 1; i__ <= i__2; ++i__) { s[i__] = w[i__] / q_ref(i__, j); /* L80: */ } temp = snrm2_(k, &s[1], &c__1); i__2 = *k; for (i__ = 1; i__ <= i__2; ++i__) { ii = indx[i__]; q_ref(i__, j) = s[ii] / temp; /* L90: */ } /* L100: */ } /* Compute the updated eigenvectors. */ L110: n2 = *n - *n1; n12 = ctot[1] + ctot[2]; n23 = ctot[2] + ctot[3]; slacpy_("A", &n23, k, &q_ref(ctot[1] + 1, 1), ldq, &s[1], &n23) ; iq2 = *n1 * n12 + 1; if (n23 != 0) { latime_1.ops += (real) n2 * 2 * *k * n23; sgemm_("N", "N", &n2, k, &n23, &c_b22, &q2[iq2], &n2, &s[1], &n23, & c_b23, &q_ref(*n1 + 1, 1), ldq); } else { slaset_("A", &n2, k, &c_b23, &c_b23, &q_ref(*n1 + 1, 1), ldq); } slacpy_("A", &n12, k, &q[q_offset], ldq, &s[1], &n12); if (n12 != 0) { latime_1.ops += (real) (*n1) * 2 * *k * n12; sgemm_("N", "N", n1, k, &n12, &c_b22, &q2[1], n1, &s[1], &n12, &c_b23, &q[q_offset], ldq); } else { slaset_("A", n1, k, &c_b23, &c_b23, &q_ref(1, 1), ldq); } L120: return 0; /* End of SLAED3 */ } /* slaed3_ */ #undef q_ref