1 files changed, 25 insertions, 0 deletions
diff --git a/src/LLBM/collect_moments.h b/src/LLBM/collect_moments.h
new file mode 100644
index 0000000..afd5d59
--- /dev/null
+++ b/src/LLBM/collect_moments.h
@@ -0,0 +1,25 @@
+#pragma once
+
+#include "concepts.h"
+
+struct CollectMomentsF {
+
+static constexpr unsigned size = 4;
+
+template <concepts::Arithmetic V>
+static void observe(V f_curr[19], V* momenta) {
+	V m0 = f_curr[10] + f_curr[13] + f_curr[17];
+	V m1 = f_curr[14] + f_curr[5] + f_curr[6];
+	V m2 = f_curr[1] + f_curr[2] + f_curr[4];
+	V m3 = m0 + m1 + m2 + f_curr[0] + f_curr[11] + f_curr[12] + f_curr[15] + f_curr[16] + f_curr[18] + f_curr[3] + f_curr[7] + f_curr[8] + f_curr[9];
+	V m4 = -f_curr[11] + f_curr[7];
+	V m5 = -f_curr[15] + f_curr[3];
+	V m6 = V{1}/m3;
+	V m7 = f_curr[0] - f_curr[18];
+	momenta[0] = m3;
+	momenta[1] = m6*(m0 + m4 + m5 - f_curr[1] - f_curr[5] - f_curr[8]);
+	momenta[2] = m6*(m1 + m4 + m7 - f_curr[12] - f_curr[13] - f_curr[4]);
+	momenta[3] = m6*(m2 + m5 + m7 - f_curr[14] - f_curr[16] - f_curr[17]);
+}
+
+};