1 files changed, 4 insertions, 3 deletions
diff --git a/src/patch/patch_interp.hh b/src/patch/patch_interp.hh
index 61dffe3..c0c6dcb 100644
--- a/src/patch/patch_interp.hh
+++ b/src/patch/patch_interp.hh
@@ -192,18 +192,19 @@ private:
 
 	// gridfn type codes for interpolator
 	// ... must be CCTK_INT so we can pass by reference to interpolator
+	// ... must be mutable so we can set values in ctor
 	// ... index is (gfn)
-	jtutil::array1d<CCTK_INT> gridfn_type_codes_;
+	mutable jtutil::array1d<CCTK_INT> gridfn_type_codes_;
 
 	// --> start of gridfn data to use for interpolation
 	//     (reset for each iperp)
 	// ... we do *not* own the pointed-to data!
 	// ... index is (gfn)
-	jtutil::array1d<fp *> gridfn_data_ptrs_;
+	mutable jtutil::array1d<fp *> gridfn_data_ptrs_;
 
 	// --> start of result buffer for interpolation
 	//     (reset for each iperp)
 	// ... we do *not* own the pointed-to data!
 	// ... index is (gfn)
-	jtutil::array1d<fp *> result_buffer_ptrs_;
+	mutable jtutil::array1d<fp *> result_buffer_ptrs_;
 	}