Merge branch 'si-to-hep' into 'master'

conversion SI to HEP

See merge request AirShowerPhysics/corsika!62

Framework/Units/PhysicalUnits.h

@@ -114,11 +114,36 @@ namespace corsika::units::si {
            static_pow<p>(corsika::units::constants::hBar) *
            static_pow<q>(corsika::units::constants::c);
   }
+  
+  template <typename DimFrom>
+  auto constexpr ConversionFactorSIToHEP() {
+    static_assert(DimFrom::dim4 == 0 && DimFrom::dim5 == 0 && DimFrom::dim6 == 0 &&
+                      DimFrom::dim7 == 0 && DimFrom::dim8 == 0,
+                  "must be pure L, M, T type");
+
+    int constexpr l = DimFrom::dim1; // SI length dim.
+    int constexpr m = DimFrom::dim2; // SI mass dim.
+    int constexpr t = DimFrom::dim3; // SI time dim.
+    
+    int constexpr p = -m;
+    int constexpr q = m + t;
+    int constexpr e = m - t - l;
+
+    using namespace detail;
+    return static_pow<e>(corsika::units::constants::hBarC) *
+           static_pow<p>(corsika::units::constants::hBar) *
+           static_pow<q>(corsika::units::constants::c);
+  }
 
   template <typename DimTo, typename DimFrom>
   auto constexpr ConvertHEPToSI(quantity<DimFrom> q) {
     return ConversionFactorHEPToSI<DimFrom, DimTo>() * q;
   }
+
+  template <typename DimFrom>
+  auto constexpr ConvertSIToHEP(quantity<DimFrom> q) {
+    return ConversionFactorSIToHEP<DimFrom>() * q;
+  }
 } // end namespace corsika::units::si
 
 /**

Framework/Units/testUnits.cc

@@ -140,4 +140,19 @@ TEST_CASE("PhysicalUnits", "[Units]") {
     REQUIRE((protonMassSI / 1.672'621'898e-27_kg) == Approx(1));
     REQUIRE((protonMassSI / (1.007'276 * corsika::units::constants::u)) == Approx(1));
   }
+
+  SECTION("SI/HEP conversion") {
+    REQUIRE(ConvertSIToHEP(units::constants::c) == Approx(1));
+    REQUIRE(ConvertSIToHEP(units::constants::hBar) == Approx(1));
+
+    {
+      auto const invLength = 1 / 197.326978_fm; // should be convertible to HEPEnergy
+      HEPEnergyType const energy = ConvertSIToHEP(invLength);
+      REQUIRE(energy / 1_MeV == Approx(1));
+    }
+
+    REQUIRE(ConvertSIToHEP(6.5823e-25_s) * 1_GeV == Approx(1).epsilon(1e-4));
+
+    REQUIRE(ConvertSIToHEP(3.8938e-32 * meter * meter) * 1_GeV * 1_GeV == Approx(1).epsilon(1e-4));
+  }
 }