message: Fix blocker formula
  I had copied it straight from the paper, without adding the factor 2 we
  have everywhere.
diff: @@ -126,7 +126,7 @@ class Sparse_rips_complex {
  // lambda[original_order]=params[sorted_order]
  for(int i=0;i<n;++i)
  lambda[sorted_points[i]] = params[i];
  - double cst = epsilon_ * (1 - epsilon_);
  + double cst = epsilon_ * (1 - epsilon_) / 2;
  auto block = [cst,&complex,&lambda](typename SimplicialComplexForRips::Simplex_handle sh){
  auto filt = complex.filtration(sh);
  auto mini = filt * cst;
  @@ -156,6 +156,7 @@ class Sparse_rips_complex {
  void compute_sparse_graph(Distance& dist, double epsilon, Filtration_value mini, Filtration_value maxi) {
  const auto& points = sorted_points; // convenience alias
  const int n = boost::size(points);
  + double cst = epsilon * (1 - epsilon) / 2;
  graph_.~Graph();
  new (&graph_) Graph(n);
  // for(auto v : vertices(g)) // doesn't work :-(
  @@ -184,10 +185,14 @@ class Sparse_rips_complex {
  // The paper has d/2 and d-lj/e to match the Cech, but we use doubles to match the Rips
  if (d * epsilon <= 2 * lj)
  alpha = d;
  - else if (d * epsilon <= li + lj && (epsilon >= 1 || d * epsilon <= lj * (1 + 1 / (1 - epsilon))))
  + else if (d * epsilon > li + lj)
  + continue;
  + else {
  alpha = (d - lj / epsilon) * 2;
  - else
  + // Keep the test exactly the same as in block to avoid inconsistencies
  + if (epsilon < 1 && alpha * cst > lj)
  continue;
  + }
  if (alpha <= maxi)
  add_edge(pi, pj, alpha, graph_);
  