From 779c0260bb65d921cc1c162ff67fe21c6c22f3d8 Mon Sep 17 00:00:00 2001
From: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Date: Tue, 29 Jul 2025 13:48:40 -0700
Subject: [PATCH] Explain why the empty-assembly case is special

---
 app-proto/src/engine.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/app-proto/src/engine.rs b/app-proto/src/engine.rs
index 55051fe..602fc57 100644
--- a/app-proto/src/engine.rs
+++ b/app-proto/src/engine.rs
@@ -383,7 +383,9 @@ pub fn realize_gram(
     // start the descent history
     let mut history = DescentHistory::new();
     
-    // handle the empty-assembly case
+    // handle the case where the assembly is empty. our general realization
+    // routine can't handle this case because it builds the Hessian using
+    // `DMatrix::from_columns`, which panics when the list of columns is empty
     let assembly_dim = guess.ncols();
     if assembly_dim == 0 {
         let result = Ok(