Function orient2dexact

tools/Predicates/predicates.c:1447–1490

(pa, pb, pc)

}

REAL orient2dexact(pa, pb, pc)
REAL *pa;
REAL *pb;
REAL *pc;
{
  INEXACT REAL axby1, axcy1, bxcy1, bxay1, cxay1, cxby1;
  REAL axby0, axcy0, bxcy0, bxay0, cxay0, cxby0;
  REAL aterms[4], bterms[4], cterms[4];
  INEXACT REAL aterms3, bterms3, cterms3;
  REAL v[8], w[12];
  int vlength, wlength;

  INEXACT REAL bvirt;
  REAL avirt, bround, around;
  INEXACT REAL c;
  INEXACT REAL abig;
  REAL ahi, alo, bhi, blo;
  REAL err1, err2, err3;
  INEXACT REAL _i, _j;
  REAL _0;

  Two_Product(pa[0], pb[1], axby1, axby0);
  Two_Product(pa[0], pc[1], axcy1, axcy0);
  Two_Two_Diff(axby1, axby0, axcy1, axcy0,
               aterms3, aterms[2], aterms[1], aterms[0]);
  aterms[3] = aterms3;

  Two_Product(pb[0], pc[1], bxcy1, bxcy0);
  Two_Product(pb[0], pa[1], bxay1, bxay0);
  Two_Two_Diff(bxcy1, bxcy0, bxay1, bxay0,
               bterms3, bterms[2], bterms[1], bterms[0]);
  bterms[3] = bterms3;

  Two_Product(pc[0], pa[1], cxay1, cxay0);
  Two_Product(pc[0], pb[1], cxby1, cxby0);
  Two_Two_Diff(cxay1, cxay0, cxby1, cxby0,
               cterms3, cterms[2], cterms[1], cterms[0]);
  cterms[3] = cterms3;

  vlength = fast_expansion_sum_zeroelim(4, aterms, 4, bterms, v);
  wlength = fast_expansion_sum_zeroelim(vlength, v, 4, cterms, w);

  return w[wlength - 1];
}

REAL orient2dslow(pa, pb, pc)
REAL *pa;