Function p_mLPshift

libpolys/polys/shiftop.cc:362–390

}

void p_mLPshift(poly m, int sh, const ring ri)
{
  if (sh == 0 || m == NULL || p_LmIsConstantComp(m,ri)) return;

  int lV = ri->isLPring;

  assume(p_mFirstVblock(m,ri) + sh >= 1);
  assume(p_mLastVblock(m,ri) + sh <= ri->N/lV);

  int *e=(int *)omAlloc((ri->N+1)*sizeof(int));
  int *s=(int *)omAlloc0((ri->N+1)*sizeof(int));
  p_GetExpV(m,e,ri);

  if (p_mLastVblock(m, e, ri) + sh > ri->N/lV)
  {
    Werror("degree bound of Letterplace ring is %d, but at least %d is needed for this shift", ri->N/lV, p_mLastVblock(m, e, ri) + sh);
  }
  for (int i = ri->N - sh*lV; i > 0; i--)
  {
    assume(e[i]<=1);
    if (e[i]==1)
    {
      s[i + (sh*lV)] = e[i]; /* actually 1 */
    }
  }
  p_SetExpV(m,s,ri);
  omFreeSize((ADDRESS) e, (ri->N+1)*sizeof(int));
  omFreeSize((ADDRESS) s, (ri->N+1)*sizeof(int));
}

void p_LPshift(poly p, int sh, const ring ri)
{