From 0e683d98cee9d25ad018cc145d62fbdbf5d280ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Max=20L=C3=BCbke?= <mluebke@uni-potsdam.de>
Date: Tue, 17 Dec 2024 13:29:07 +0100
Subject: [PATCH] feat: enhance LookupKey with const isnan method and
 comparison operator

---
 src/Chemistry/SurrogateModels/LookupKey.hpp | 6 +++++-
 src/Chemistry/SurrogateModels/Rounding.hpp  | 8 ++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/Chemistry/SurrogateModels/LookupKey.hpp b/src/Chemistry/SurrogateModels/LookupKey.hpp
index 6e7b0681c..87c626f77 100644
--- a/src/Chemistry/SurrogateModels/LookupKey.hpp
+++ b/src/Chemistry/SurrogateModels/LookupKey.hpp
@@ -21,7 +21,7 @@ struct Lookup_SC_notation {
     return {SC_NOTATION_EXPONENT_MASK, SC_NOTATION_SIGNIFICANT_MASK};
   }
 
-  constexpr bool isnan() {
+  constexpr bool isnan() const {
     return !!(exp == SC_NOTATION_EXPONENT_MASK &&
               significant == SC_NOTATION_SIGNIFICANT_MASK);
   }
@@ -35,6 +35,10 @@ union Lookup_Keyelement {
     return std::memcmp(this, &other, sizeof(Lookup_Keyelement)) == 0 ? true
                                                                      : false;
   }
+
+  template <typename T> bool operator>(const T &other) const {
+    return this->sc_notation.significant > other;
+  }
 };
 
 class LookupKey : public std::vector<Lookup_Keyelement> {
diff --git a/src/Chemistry/SurrogateModels/Rounding.hpp b/src/Chemistry/SurrogateModels/Rounding.hpp
index 688ac4707..6656b8026 100644
--- a/src/Chemistry/SurrogateModels/Rounding.hpp
+++ b/src/Chemistry/SurrogateModels/Rounding.hpp
@@ -65,6 +65,14 @@ public:
                           std::uint32_t signif) {
     Lookup_Keyelement new_val = value;
 
+    if (value.sc_notation.isnan()) {
+      return {.sc_notation = Lookup_SC_notation::nan()};
+    }
+
+    if (signif == 0) {
+      return {.sc_notation = {0, value > 0}};
+    }
+
     std::uint32_t diff_signif =
         static_cast<std::uint32_t>(
             std::ceil(std::log10(std::abs(value.sc_notation.significant)))) -