Function PermuteNodesInPlace

tensorflow/core/grappler/utils.cc:402–419

Every permutation is a product of one or more cycles. Iterate over the cycles in the permutation, and convert each of those into a product of transpositions (swaps): https://en.wikipedia.org/wiki/Cyclic_permutation

// in the permutation, and convert each of those into a product of
// transpositions (swaps): https://en.wikipedia.org/wiki/Cyclic_permutation
void PermuteNodesInPlace(GraphDef* graph, std::vector<int>* permutation,
                         bool invert_permutation) {
  CHECK_EQ(graph->node_size(), permutation->size());
  std::vector<int> inv_perm(permutation->size(), 0);
  if (invert_permutation) {
    for (size_t n = 0; n < permutation->size(); ++n) {
      inv_perm[(*permutation)[n]] = n;
    }
    permutation->swap(inv_perm);
  }
  for (std::size_t n = 0; n + 1 < permutation->size(); ++n) {
    while (n != (*permutation)[n]) {
      std::size_t r = (*permutation)[n];
      graph->mutable_node()->SwapElements(n, r);
      std::swap((*permutation)[n], (*permutation)[r]);
    }
  }
}

void DedupControlInputs(NodeDef* node) {
  std::unordered_set<string> inputs;