From 8823afc8d255e2d8577a77799746a98009142861 Mon Sep 17 00:00:00 2001
From: Zeno Rogue <zeno@attnam.com>
Date: Mon, 15 Jul 2024 09:03:58 +0200
Subject: [PATCH] twist::formula_exp now returns shiftpoint

---
 hyperpoint.cpp   | 4 +++-
 nonisotropic.cpp | 8 ++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/hyperpoint.cpp b/hyperpoint.cpp
index 6e9ffd56..43c13669 100644
--- a/hyperpoint.cpp
+++ b/hyperpoint.cpp
@@ -155,6 +155,8 @@ struct transmatrix {
 struct shiftpoint {
   hyperpoint h;
   ld shift;
+  shiftpoint() {}
+  shiftpoint(hyperpoint _h, ld _shift) : h(_h), shift(_shift) {}
   ld& operator [] (int i) { return h[i]; }
   const ld& operator [] (int i) const { return h[i]; }
   inline friend shiftpoint operator + (const shiftpoint& h, const hyperpoint& h2) {
@@ -1651,7 +1653,7 @@ EX hyperpoint direct_exp(hyperpoint v) {
   #endif
   #if MAXMDIM >= 4
   if(nil) return nilv::formula_exp(v);
-  if(sl2 || stretch::in()) return stretch::mstretch ? nisot::numerical_exp(v) : twist::formula_exp(v);
+  if(sl2 || stretch::in()) return stretch::mstretch ? nisot::numerical_exp(v) : unshift(twist::formula_exp(v));
   #endif
   if(gproduct) return product::direct_exp(v);
   ld d = hypot_d(GDIM, v);
diff --git a/nonisotropic.cpp b/nonisotropic.cpp
index 2f617b8f..36ef1872 100644
--- a/nonisotropic.cpp
+++ b/nonisotropic.cpp
@@ -2570,11 +2570,11 @@ EX namespace twist {
 
   /** @brief exponential function for both slr and Berger sphere */
 
-  EX hyperpoint formula_exp(hyperpoint vel) {
+  EX shiftpoint formula_exp(hyperpoint vel) {
     bool sp = sphere;
     ld K = sp ? 1 : -1;
 
-    if(vel[0] == 0 && vel[1] == 0 && vel[2] == 0) return C0;
+    if(vel[0] == 0 && vel[1] == 0 && vel[2] == 0) return shiftpoint(C0,0);
   
     ld len = hypot_d(3, vel);
   
@@ -2606,7 +2606,7 @@ EX namespace twist {
       ld xy = sr * sinh(k);
       ld zw = cr * sinh(k);
       
-      return hyperpoint(K*xy * cos(u+beta), K*xy * sin(u+beta), zw * cos(u) - cosh(k) * sin(u), zw * sin(u) + cosh(k)*cos(u));
+      return shiftpoint(hyperpoint(K*xy * cos(beta), K*xy * sin(beta), zw, cosh(k)), u);
       }
   
     else {
@@ -2624,7 +2624,7 @@ EX namespace twist {
       ld xy = sr * sin(k);  
       ld zw = cr * sin(k);    
       
-      return hyperpoint(K*xy * cos(u+beta), K*xy * sin(u+beta), zw * cos(u) - cos(k) * sin(u), zw * sin(u) + cos(k)*cos(u));
+      return shiftpoint(hyperpoint(K*xy * cos(u+beta), K*xy * sin(u+beta), zw * cos(u) - cos(k) * sin(u), zw * sin(u) + cos(k)*cos(u)), 0);
       }
     }