From 1160baa61bad605cf8a1d583e8ae356a54a942df Mon Sep 17 00:00:00 2001
From: Jaron Kent-Dobias <jaron@kent-dobias.com>
Date: Thu, 26 Jul 2018 16:18:40 -0400
Subject: many changes, including new spin spaces and groups and cleaning up
 core library code

---
 lib/circle_group.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 lib/circle_group.h

(limited to 'lib/circle_group.h')

diff --git a/lib/circle_group.h b/lib/circle_group.h
new file mode 100644
index 0000000..cb7cadd
--- /dev/null
+++ b/lib/circle_group.h
@@ -0,0 +1,46 @@
+#pragma once
+
+#include "angle.h"
+
+class circle_group_t {
+  public:
+    bool is_reflection;
+    double x;
+
+    circle_group_t() : is_reflection(false), x(0) {}
+    circle_group_t(bool x, double y) : is_reflection(x), x(y) {}
+
+    angle_t act(const angle_t& theta) const {
+      if (is_reflection) {
+        return angle_t(fmod(2 * M_PI + x - theta.x, 2 * M_PI));
+      } else {
+        return angle_t(fmod(x + theta.x, 2 * M_PI));
+      }
+    }
+
+    circle_group_t act(const circle_group_t& r) const {
+      if (is_reflection) {
+        return circle_group_t(!r.is_reflection, fmod(2 * M_PI + x - r.x, 2 * M_PI));
+      } else {
+        return circle_group_t(r.is_reflection, fmod(x + r.x, 2 * M_PI));
+      }
+    }
+
+    angle_t act_inverse(const angle_t& theta) const {
+      if (is_reflection) {
+        return act(theta);
+      } else {
+        return angle_t(fmod(2 * M_PI + theta.x - x, 2 * M_PI));
+      }
+    }
+
+    circle_group_t act_inverse(const circle_group_t& r) const {
+      if (is_reflection) {
+        return act(r);
+      } else {
+        return circle_group_t(r.is_reflection, fmod(2 * M_PI + r.x - x, 2 * M_PI));
+      }
+    }
+};
+
+
-- 
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