From a7888d473c97b00800a89d345b0ce883c197246f Mon Sep 17 00:00:00 2001
From: Yuval Tassa <tassa@google.com>
Date: Wed, 1 Feb 2023 01:26:47 -0800
Subject: [PATCH] `mju_transposeSparse`: extract local integer, remove extra
 blank line.

PiperOrigin-RevId: 506243573
Change-Id: Ia573c9289ef1deb1cc7b5477d441752370caa470
---
 src/engine/engine_util_sparse.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/engine/engine_util_sparse.c b/src/engine/engine_util_sparse.c
index ca28e334..6c7f869f 100644
--- a/src/engine/engine_util_sparse.c
+++ b/src/engine/engine_util_sparse.c
@@ -550,15 +550,13 @@ void mju_transposeSparse(mjtNum* res, const mjtNum* mat, int nr, int nc,
 
   // iterate through each non-zero entry of mat
   for (int i = 0; i<nnz; i++) {
-
     // iterate to get to the current row (skipping rows with all zeros)
     while ((i-rowadr[r]) >= rownnz[r]) r++;
 
-    // row index becomes the column index
-    res[res_rowadr[colind[i]]] = mat[i];
-
-    // column index becomes the row index (increment the rowadr)
-    res_colind[res_rowadr[colind[i]]++] = r;
+    // swap rows with columns and increment res_rowadr
+    int c = res_rowadr[colind[i]]++;
+    res[c] = mat[i];
+    res_colind[c] = r;
   }
 
   // shift back row addresses