log fixes

LoopModels · Feb 16, 2024 · 5f94615 · 5f94615
1 parent 5738844
commit 5f94615
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/include/Math/Dual.hpp b/include/Math/Dual.hpp
@@ -809,12 +809,13 @@ constexpr auto softplus(const Dual<T, N> &x) -> Dual<T, N> {
 }
 template <class T, ptrdiff_t N>
 constexpr auto log(const Dual<T, N> &x) -> Dual<T, N> {
-  return {log2(x.value()), x.gradient() / x.value()};
+  constexpr double logof2 = 0.6931471805599453; // log(2);
+  return {log2(x.value()) * logof2, x.gradient() / x.value()};
 }
 template <class T, ptrdiff_t N>
 constexpr auto log2(const Dual<T, N> &x) -> Dual<T, N> {
-  constexpr double log2 = 0.6931471805599453; // log(2);
-  return {log2(x.value()), x.gradient() / (log2 * x.value())};
+  constexpr double logof2 = 0.6931471805599453; // log(2);
+  return {log2(x.value()), x.gradient() / (logof2 * x.value())};
 }
 
 constexpr auto dval(double &x) -> double & { return x; }

diff --git a/include/Math/Exp.hpp b/include/Math/Exp.hpp
@@ -430,7 +430,8 @@ template <int l = 8> constexpr auto smax(auto x, auto y) {
 
 template <int l = 8> constexpr auto smax(auto x, auto y, auto z) {
   double m = std::max(std::max(value(x), value(y)), value(z));
-  return m + log(exp(l * (x - m)) + exp(l * (y - m)) + exp(l * (z - m))) / l;
+  constexpr double f = l, i = 1 / f;
+  return m + log(exp(f * (x - m)) + exp(f * (y - m)) + exp(f * (z - m))) * i;
 }
 template <int l = 8> constexpr auto smin(auto x, auto y) {
   return smax<-l>(x, y);