From 698ca0f834e4951bd6fdd4a2eaffad52b6d79063 Mon Sep 17 00:00:00 2001
From: Joseph Edwards <josephdavidedwards@gmail.com>
Date: Wed, 13 Nov 2024 12:10:05 +0000
Subject: [PATCH] Add current size

---
 include/libsemigroups/schreier-sims.hpp |  2 ++
 include/libsemigroups/schreier-sims.tpp | 15 ++++++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/libsemigroups/schreier-sims.hpp b/include/libsemigroups/schreier-sims.hpp
index 540c5496e..f1bbe1f1d 100644
--- a/include/libsemigroups/schreier-sims.hpp
+++ b/include/libsemigroups/schreier-sims.hpp
@@ -667,6 +667,8 @@ namespace libsemigroups {
     // not noexcept because run isn't
     [[nodiscard]] uint64_t size();
 
+    [[nodiscard]] uint64_t current_size() const;
+
     //! \brief Sift an element through the stabiliser chain in-place.
     //!
     //! Sift an element through the stabiliser chain in-place.
diff --git a/include/libsemigroups/schreier-sims.tpp b/include/libsemigroups/schreier-sims.tpp
index 4237a59a2..03dcb1d92 100644
--- a/include/libsemigroups/schreier-sims.tpp
+++ b/include/libsemigroups/schreier-sims.tpp
@@ -182,6 +182,19 @@ namespace libsemigroups {
     return out;
   }
 
+  template <size_t N, typename Point, typename Element, typename Traits>
+  uint64_t SchreierSims<N, Point, Element, Traits>::current_size() const {
+    // TODO(later) check if product overflows?
+    if (empty()) {
+      return 1;
+    }
+    uint64_t out = 1;
+    for (index_type i = 0; i < _base_size; i++) {
+      out *= _orbits.size(i);
+    }
+    return out;
+  }
+
   template <size_t N, typename Point, typename Element, typename Traits>
   bool SchreierSims<N, Point, Element, Traits>::currently_contains(
       const_element_reference x) const {
@@ -652,7 +665,7 @@ namespace libsemigroups {
     }
 
     if (S.finished()) {
-      size_t size = const_cast<SchreierSims<N>&>(S).size();
+      size_t size = S.current_size();
 
       out = fmt::format("<SchreierSims with {} generator{}, base {} & size {}>",
                         nr_generators,