From 96c7350aa100589fd879a4d6de6f96031dbe5410 Mon Sep 17 00:00:00 2001
From: Yingjie Wang <phywyj@gmail.com>
Date: Sat, 28 Feb 2026 02:04:51 -0500
Subject: [PATCH] update: allow -DFLAT=1 to set a flat spacetime without black
 hole during compilation

---
 src/common.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/common.h b/src/common.h
index cf9217f..8919bbb 100644
--- a/src/common.h
+++ b/src/common.h
@@ -7,7 +7,9 @@
 
 #define POW2(x) ((x)*(x))
 
+#ifndef FLAT
 #define FLAT 0
+#endif
 #define PI 3.1415926535897932384626433832795028841971693993751058
 #define Rs 1
 #define M (FLAT ? 0 : 0.5*Rs)