From f4b392687bebc0953aee91b014384e10cb4846b1 Mon Sep 17 00:00:00 2001
From: labourasse <labourassee@gmail.com>
Date: Tue, 5 Nov 2024 08:34:51 +0100
Subject: [PATCH] Frobenius norm for matrix
---
src/algebra/TinyMatrix.hpp | 15 +++++++++++++++
tests/test_TinyMatrix.cpp | 10 ++++++++++
2 files changed, 25 insertions(+)
diff --git a/src/algebra/TinyMatrix.hpp b/src/algebra/TinyMatrix.hpp
index 94590ff65..12122a874 100644
--- a/src/algebra/TinyMatrix.hpp
+++ b/src/algebra/TinyMatrix.hpp
@@ -504,6 +504,21 @@ trace(const TinyMatrix<N, N, T>& A)
return t;
}
+template <size_t N, typename T>
+PUGS_INLINE T
+frobeniusNorm(const TinyMatrix<N, N, T>& A)
+{
+ static_assert(std::is_arithmetic<T>::value, "norm is not defined for non-arithmetic types");
+
+ T t = 0;
+ for (size_t i = 0; i < N; ++i) {
+ for (size_t j = 0; j < N; ++j) {
+ t += A(i, j) * A(i, j);
+ }
+ }
+ return std::sqrt(t);
+}
+
template <size_t N, typename T>
PUGS_INLINE constexpr TinyMatrix<N, N, T> inverse(const TinyMatrix<N, N, T>& A);
diff --git a/tests/test_TinyMatrix.cpp b/tests/test_TinyMatrix.cpp
index 80159a021..f6d132bb7 100644
--- a/tests/test_TinyMatrix.cpp
+++ b/tests/test_TinyMatrix.cpp
@@ -209,6 +209,16 @@ TEST_CASE("TinyMatrix", "[algebra]")
REQUIRE(trace(TinyMatrix<4>(1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 2, 0, 0, 2, 2)) == 1 + 0 + 1 + 2);
}
+ SECTION("checking for norm calculations")
+ {
+ REQUIRE(frobeniusNorm(TinyMatrix<1, 1, int>(6)) == 6);
+ REQUIRE(frobeniusNorm(TinyMatrix<2, 2>(5, 1, -3, 6)) == Catch::Approx(std::sqrt(25 + 1 + 9 + 36)).epsilon(1E-14));
+ REQUIRE(frobeniusNorm(TinyMatrix<4>(1, 2.3, 7, -6.2, 3, 4, 9, 1, 4.1, 5, 2, -3, 2, 27, 3, 17.5)) ==
+ Catch::Approx(std::sqrt(1 + 2.3 * 2.3 + 7 * 7 + 6.2 * 6.2 + 9 + 16 + 81 + 1 + 4.1 * 4.1 + 25 + 4 + 9 + 4 +
+ 27 * 27 + 9 + 17.5 * 17.5))
+ .epsilon(1E-14));
+ }
+
SECTION("checking for inverse calculations")
{
{
--
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