docs: def _populate_tournament_payoff_array0(payoff_array, k, indices, indptr):
      """
      Populate `payoff_array` with the payoff values for player 0 in the
      tournament game given a random tournament graph in CSR format.
  
      Parameters
      ----------
      payoff_array : ndarray(float, ndim=2)
          ndarray of shape (n, m), where m = n choose k, prefilled with
          zeros. Modified in place.
      k : scalar(int)
          Size of the subsets of nodes.
      indices : ndarray(int, ndim=1)
          CSR format index array of the adjacency matrix of the tournament
          graph.
      indptr : ndarray(int, ndim=1)
          CSR format index pointer array of the adjacency matrix of the
          tournament graph.
  
      """
      n = payoff_array.shape[0]
      X = np.empty(k, dtype=np.int_)
      a = np.empty(k, dtype=np.int_)
      for i in range(n):
          d = indptr[i+1] - indptr[i]
          if d >= k:
              for j in range(k):
                  a[j] = j
              while a[-1] < d:
                  for j in range(k):
                      X[j] = indices[indptr[i]+a[j]]
                  payoff_array[i, k_array_rank_jit(X)] = 1
                  a = next_k_array(a)