bounds()

void SchurRing::bounds ( int & lo, int & hi )

private

Definition at line 137 of file schur.cpp.

{
  int i, k;
  int x = _SMfilled.xloc[_SMcurrent];
  int y = _SMfilled.yloc[_SMcurrent];
 
  // First set the high bound, using info from the "one to the right"
  // in the reverse lex filled skew tableau.
 
  if (y == _SMfilled.p[x])  // There is not one to the right
    {
      hi = nvars_;
      for (k = 1; k <= nvars_; k++)
        if (_SMtab.p[k] == 0)
          {
            hi = k;
            break;
          }
    }
  else  // note that the case _SMcurrent==1 will be handled
    {   // in the previous statement.
      hi = _SMtab.xloc[_SMcurrent - 1];
    }
 
  // Now we set the lo bound, using info from the "one above"
 
  if (x == 1 || y <= _SMfilled.lambda[x - 1])
    lo = 1;  // There is not one above
  else
    {
      int above = _SMcurrent - _SMfilled.p[x] + _SMfilled.lambda[x - 1];
      int xabove = _SMtab.xloc[above];
      int yabove = _SMtab.yloc[above];
      for (i = xabove + 1; i <= hi; i++)
        if (_SMtab.p[i] < yabove) break;
      lo = i;
    }
}

References _SMcurrent, _SMfilled, _SMtab, PolynomialRing::nvars_, and x.

Referenced by SM().