From dd179e10d6327af467aff7d97a94664ce1df1016 Mon Sep 17 00:00:00 2001
From: Relintai <relintai@protonmail.com>
Date: Wed, 27 Dec 2023 16:10:45 +0100
Subject: [PATCH] Optimized MLPPMatrix::det a little.

---
 mlpp/lin_alg/mlpp_matrix.cpp | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/mlpp/lin_alg/mlpp_matrix.cpp b/mlpp/lin_alg/mlpp_matrix.cpp
index ef3f158..b676fb4 100644
--- a/mlpp/lin_alg/mlpp_matrix.cpp
+++ b/mlpp/lin_alg/mlpp_matrix.cpp
@@ -1546,10 +1546,6 @@ real_t MLPPMatrix::detb(const Ref<MLPPMatrix> &A, int d) const {
 	ERR_FAIL_COND_V(!A.is_valid(), 0);
 
 	real_t deter = 0;
-	Ref<MLPPMatrix> B;
-	B.instance();
-	B->resize(Size2i(d, d));
-	B->fill(0);
 
 	/* This is the base case in which the input is a 2x2 square matrix.
 	Recursion is performed unless and until we reach this base case,
@@ -1557,6 +1553,11 @@ real_t MLPPMatrix::detb(const Ref<MLPPMatrix> &A, int d) const {
 	if (d == 2) {
 		return A->element_get(0, 0) * A->element_get(1, 1) - A->element_get(0, 1) * A->element_get(1, 0);
 	} else {
+		Ref<MLPPMatrix> B;
+		B.instance();
+		B->resize(Size2i(d, d));
+		B->fill(0);
+
 		for (int i = 0; i < d; i++) {
 			int sub_i = 0;
 			for (int j = 1; j < d; j++) {
@@ -1667,9 +1668,13 @@ Ref<MLPPMatrix> MLPPMatrix::adjoint() const {
 			Ref<MLPPMatrix> cof = cofactor(_size.y, i, j);
 			// 1 if even, -1 if odd
 			int sign = (i + j) % 2 == 0 ? 1 : -1;
-			adj->element_set(j, i, sign * cof->det(int(_size.y) - 1));
+
+			real_t d = cof->det(int(_size.y) - 1);
+
+			adj->element_set(j, i, sign * d);
 		}
 	}
+
 	return adj;
 }
 void MLPPMatrix::adjointo(Ref<MLPPMatrix> out) const {