Function multring

Singular/dyn_modules/Order/nforder.cpp:553–604

#ifdef HAVE_RINGS
number multring(bigintmat *nbase, nforder *o, number p) {
  coeffs R = o->basecoeffs();
  number divi;
  int n = o->getDim();

  bigintmat *inv = new bigintmat(n, n, R);
  divi = nbase->pseudoinv(inv);

  // Zusammenbau der "langen" Matrix
  bigintmat *lon = new bigintmat(n, 0, R);
  bigintmat *oldlon;
  bigintmat *mm = new bigintmat(n, n, R);
  bigintmat *temp = new bigintmat(n, 1, R);
  bigintmat *nochnetemp = new bigintmat(n, n, R);

  for (int i=1; i<=n; i++) {
    nbase->getcol(i, temp);
    o->multmap(temp, mm);
    bimMult(inv, mm, nochnetemp);
    mm->copy(nochnetemp);
    mm->inpTranspose();
    oldlon = lon;
    lon = new bigintmat(n, (i)*n, o->basecoeffs());
    lon->concatcol(oldlon, mm);
    delete oldlon;
  }

  lon->skaldiv(divi);

  bigintmat * red;
  if (1) {
    bigintmat * cmp = lon->modhnf(p, o->basecoeffs());
    red = cmp;
  } else {
    lon->hnf();
    red = new bigintmat(n, n, o->basecoeffs());
    lon->getColRange((n-1)*n+1, n, red);
  }
  delete lon;
  red->inpTranspose();

  number divisor = red->pseudoinv(nbase);
  nbase->hnf();

  delete inv;
  delete mm;
  delete temp;
  delete red;
  delete nochnetemp;
  n_Delete(&divi, o->basecoeffs());
  return divisor;
}
#endif

#ifdef HAVE_RINGS