From 418eb072dcdb7330e32f421df680a86ef76780a9 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Fri, 6 May 2022 02:50:30 +0200
Subject: [PATCH] lie_exp approximation for other geometries

---
 hypgraph.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/hypgraph.cpp b/hypgraph.cpp
index 4eb30fa3..06b45a3b 100644
--- a/hypgraph.cpp
+++ b/hypgraph.cpp
@@ -2976,8 +2976,15 @@ EX hyperpoint lie_exp(hyperpoint h) {
     z = h[2] * log(3);
     h[1] *= (exp(+z) - 1) / z;
     }
-  else if(sl2) {
-    /* not implemented */
+  else {
+    /* not implemented -- approximate for now */
+    const int steps = 16;
+    h /= (1<<steps);
+    h[3] = 1;
+    normalize(h);
+    transmatrix T = eupush(h);
+    for(int i=0; i<16; i++) T = T * T;
+    h = tC0(T);
     }
   return h;
   }