mult_terms()

ring_elem SchurRing2::mult_terms ( const_schur_partition a, const_schur_partition b )

private

Definition at line 867 of file schur2.cpp.

{
  int maxsize = (a[0] - 1 + b[0] - 1) + 1;  // this is the max number of
                                            // elements in the output partition,
                                            // plus one
 
  schur_partition lambda = ALLOCATE_EXPONENTS(sizeof(schur_word) * maxsize);
  schur_partition p = ALLOCATE_EXPONENTS(sizeof(schur_word) * maxsize);
 
  // Second: make the skew partition (note: r,s>=1)
  // this is: if a = r+1 a1 a2 ... ar
  //             b = s+1 b1 b2 ... bs
  // p is:
  //   (r+s+1) b1+a1 b1+a2 ... b1+ar b1 b2 ... bs
  // lambda is:
  //   (r+1)   b1    b1    ... b1    0  0  ... 0
 
  int r = a[0] - 1;
  int s = b[0] - 1;
  int c = b[1];
 
  assert(r + s + 1 == maxsize);
 
  for (int i = 1; i <= r; i++)
    {
      assert(i < maxsize);
      p[i] = c + a[i];
      lambda[i] = c;
    }
  for (int i = r + 1; i < r + s + 1; i++)
    {
      assert(i < maxsize);
      p[i] = b[i - r];
      lambda[i] = 0;
    }
  p[0] = r + s + 1;
  lambda[0] = r + 1;
  return skew_schur(lambda, p);
}

References ALLOCATE_EXPONENTS, p, s, and skew_schur().

Referenced by mult().