power() [1/2]

ring_elem PolyRing::power ( const ring_elem f, int n ) const

virtual

Reimplemented from Ring.

Reimplemented in SchurRing, SkewPolynomialRing, SolvableAlgebra, and WeylAlgebra.

Definition at line 918 of file poly.cpp.

{
  ring_elem ff;
 
  if (n > 0)
    ff = f0;
  else if (n < 0)
  {
    ff = invert(f0);
    n = -n;
  }
  else
    return from_long(1);
 
  if(!characteristic())
  {
    return power_direct(ff, n);
  }
  else
  {
    long p=characteristic(), pk=1;
    ring_elem result = from_long(1);
    ring_elem gg = copy(ff), temp; // no need to copy, just the correct number of terms
 
    while(n)
    {
      for(Nterm *it=ff, *jt=gg; it!=nullptr; it=it->next, jt=jt->next)
      {
        jt->coeff = K_->power(it->coeff, pk);
        M_->power(it->monom, pk, jt->monom);
      }
 
      temp = power_direct(gg, n%p);
      result = mult(result, temp);
 
      pk *= p;
      n /= p;
    }
 
    return result;
  }
}

References Ring::characteristic(), copy(), from_long(), invert(), PolynomialRing::K_, PolynomialRing::M_, mult(), p, power_direct(), and result().