From 79e9ff7c8bdc8bd705639e60bb90f8bb050003e3 Mon Sep 17 00:00:00 2001
From: Matthew Turk <matthewturk@gmail.com>
Date: Wed, 21 Jun 2023 10:21:29 -0500
Subject: [PATCH] Reduce the number of passes over the grid array.

---
 yt/geometry/grid_container.pyx | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/yt/geometry/grid_container.pyx b/yt/geometry/grid_container.pyx
index d65a687182e..8f96bf8192b 100644
--- a/yt/geometry/grid_container.pyx
+++ b/yt/geometry/grid_container.pyx
@@ -204,11 +204,7 @@ cdef class GridTree:
         data.array = <void*>mask.buf
         self.visit_grids(&data, grid_visitors.mask_cells, selector)
         self.mask = mask
-        size = 0
-        self.setup_data(&data)
-        data.array = <void*>(&size)
-        self.visit_grids(&data,  grid_visitors.count_cells, selector)
-        return size
+        return mask.count()
 
     def select_icoords(self, SelectorObject selector, np.uint64_t size = -1):
         # Fill icoords with a selector