test some equation units and add some docs (#315)

* test some equation units and add some docs

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

docs/user-guide/defined_units.rst

@@ -786,6 +786,9 @@ Some special units that were not otherwise characterized in namespace `units::pr
 - mach - mach number(multiplier of the speed of sound)
 - rootHertz - square root of Hertz, this is a special handling unit that triggers some specific behavior to handle it.
 - rootMeter - square root of meter, this is a special handling unit that triggers some specific behavior to handle it.
+- degreeAPI - API scale for measuring liquid density typically petroleum based products
+- degreeBaumeLight - scale for measuring liquid density for liquids lighter than water
+- debreeBaumeHeavy - scale for measuring liquid density for liquids heavier than water
 
 
 Other Units
@@ -807,6 +810,7 @@ Units related to climate in namespace `units::precise::climate`
 
 - gwp - global warming potential
 - gtp - global temperature potential
+- odp - ozone depletion unit
 
 Speed Units
 ============================

test/test_equation_units.cpp

@@ -357,7 +357,7 @@ TEST(logUnits, error)
         20.0, precise::log::dBA * precise::m / precise::s, precise::m)));
 }
 
-TEST(otherUnits, prismDiopter)
+TEST(otherEqUnits, prismDiopter)
 {
     EXPECT_NEAR(
         convert(1, precise::deg, precise::clinical::prism_diopter),
@@ -369,7 +369,7 @@ TEST(otherUnits, prismDiopter)
         0.005);
 }
 
-TEST(otherUnits, saffirSimpson)
+TEST(otherEqUnits, saffirSimpson)
 {
     EXPECT_EQ(
         std::floor(
@@ -395,7 +395,7 @@ TEST(otherUnits, saffirSimpson)
         3.0);
 }
 
-TEST(otherUnits, saffirSimpson2Speed)
+TEST(otherEqUnits, saffirSimpson2Speed)
 {
     EXPECT_NEAR(
         convert(3.0, precise::special::sshws, precise::m / precise::s),
@@ -453,7 +453,7 @@ INSTANTIATE_TEST_SUITE_P(
     beaufort,
     ::testing::ValuesIn(testBValues));
 
-TEST(otherUnits, saffirSimpson2Sbeaufort)
+TEST(otherEqUnits, saffirSimpson2Sbeaufort)
 {
     EXPECT_NEAR(
         convert(12.1, precise::special::beaufort, precise::special::sshws),
@@ -494,7 +494,7 @@ INSTANTIATE_TEST_SUITE_P(
     fujita,
     ::testing::ValuesIn(testFValues));
 
-TEST(otherUnits, saffirSimpson2Sfujita)
+TEST(otherEqUnits, saffirSimpson2Sfujita)
 {
     EXPECT_NEAR(
         convert(1.0, precise::special::fujita, precise::special::sshws),
@@ -506,7 +506,7 @@ TEST(otherUnits, saffirSimpson2Sfujita)
         0.05);
 }
 
-TEST(otherUnits, trits)
+TEST(otherEqUnits, trits)
 {
     EXPECT_NEAR(
         convert(1.0, precise::data::trit, precise::data::bit_s),
@@ -531,7 +531,7 @@ TEST(otherUnits, trits)
         convert(9, precise::data::digits, precise::data::trit), 18.86, 0.01);
 }
 
-TEST(otherUnits, digits)
+TEST(otherEqUnits, digits)
 {
     EXPECT_NEAR(
         convert(12.0, precise::data::digits, precise::data::bit_s),
@@ -542,7 +542,7 @@ TEST(otherUnits, digits)
     EXPECT_NEAR(convert(1.0, precise::data::digits, precise::one), 10.0, 0.01);
 }
 
-TEST(otherUnits, Richter)
+TEST(otherEqUnits, Richter)
 {
     auto conv5 = convert(
         5.0, precise::special::moment_magnitude, precise::N * precise::m);
@@ -567,7 +567,7 @@ TEST(otherUnits, Richter)
     EXPECT_NEAR(conv7 / conv5, 1000.0, 10.0);
 }
 
-TEST(otherUnits, momentEnergy)
+TEST(otherEqUnits, momentEnergy)
 {
     auto conv5 = convert(5.0, precise::special::moment_energy, precise::J);
     EXPECT_FALSE(std::isnan(conv5));
@@ -588,21 +588,53 @@ TEST(otherUnits, momentEnergy)
     EXPECT_NEAR(conv7 / conv5, 1000.0, 10.0);
 }
 
-TEST(otherUnits, unknownEQ)
+TEST(otherEqUnits, unknownEQ)
 {
-    auto eq18 = precise_unit(precise::custom::equation_unit(18));
-    auto eq19 = precise_unit(precise::custom::equation_unit(19));
-    EXPECT_EQ(convert(1.92, eq18, precise::one), 1.92);
+    auto eq20 = precise_unit(precise::custom::equation_unit(21));
+    auto eq21 = precise_unit(precise::custom::equation_unit(22));
+    EXPECT_EQ(convert(1.92, eq20, precise::one), 1.92);
 
-    auto conv7 = convert(7.0, eq18, eq19 * precise::W);
+    auto conv7 = convert(7.0, eq21, eq20 * precise::W);
     EXPECT_TRUE(std::isnan(conv7));
 
-    EXPECT_EQ(convert(1.927, eq18 * precise::W, eq19 * precise::W), 1.927);
+    EXPECT_EQ(convert(1.927, eq20 * precise::W, eq20 * precise::W), 1.927);
+}
+
+TEST(otherEqUnits, APIgravity)
+{
+    auto apiG = precise::special::degreeAPI;
+    // gasoline
+    EXPECT_NEAR(convert(56.98, apiG, precise::g / precise::mL), 0.7508, 0.0001);
+    EXPECT_NEAR(
+        convert(0.750743, precise::g / precise::mL, apiG), 56.98, 0.001);
+    // kerosene
+    EXPECT_NEAR(
+        convert(50.9, apiG, precise::g / precise::mL), 0.775768, 0.0001);
+    EXPECT_NEAR(convert(0.775768, precise::g / precise::mL, apiG), 50.9, 0.001);
+}
+
+TEST(otherEqUnits, degreeBaume)
+{
+    auto degBL = precise::special::degreeBaumeLight;
+    EXPECT_NEAR(convert(10, degBL, precise::g / precise::mL), 1.0000, 0.0001);
+    EXPECT_NEAR(convert(1.0000, precise::g / precise::mL, degBL), 10.0, 0.001);
+    EXPECT_NEAR(convert(26.075, degBL, precise::g / precise::mL), 0.897, 0.001);
+    EXPECT_NEAR(convert(0.897, precise::g / precise::mL, degBL), 26.075, 0.001);
+    EXPECT_NEAR(convert(43.91, degBL, precise::g / precise::mL), 0.805, 0.001);
+    EXPECT_NEAR(convert(0.805, precise::g / precise::mL, degBL), 43.91, 0.01);
+
+    auto degBH = precise::special::degreeBaumeHeavy;
+    EXPECT_NEAR(convert(0, degBH, precise::g / precise::mL), 1.0000, 0.0001);
+    EXPECT_NEAR(convert(1.0000, precise::g / precise::mL, degBH), 0.0, 0.001);
+    EXPECT_NEAR(convert(15.0, degBH, precise::g / precise::mL), 1.115, 0.001);
+    EXPECT_NEAR(convert(1.115, precise::g / precise::mL, degBH), 14.955, 0.001);
+    EXPECT_NEAR(convert(69.0, degBH, precise::g / precise::mL), 1.908, 0.001);
+    EXPECT_NEAR(convert(1.908, precise::g / precise::mL, degBH), 69.0, 0.005);
 }
 
 #ifndef UNITS_HEADER_ONLY
 
-TEST(otherUnits, strings)
+TEST(otherEqUnits, strings)
 {
     precise_unit eq18(1.36, precise::custom::equation_unit(18));
 

units/r20_conv.cpp

@@ -1613,9 +1613,9 @@ namespace precise {
         unitD{"J10", "percent per millimetre", percent / mm},
         unitD{"J12", "per mille per psi", {0.001, pressure::psi.inv()}},
         unitD{"J13", "degree API", special::degreeAPI},
-        unitD{"J14", "degree Baume", special::degreeBaume},
-        unitD{"J15", "degree Baume (US heavy)", special::degreeBaume},
-        unitD{"J16", "degree Baume (US light)", special::degreeBaume},
+        unitD{"J14", "degree Baume", special::degreeBaumeLight},
+        unitD{"J15", "degree Baume (US heavy)", special::degreeBaumeLight},
+        unitD{"J16", "degree Baume (US light)", special::degreeBaumeHeavy},
         unitD{
             "J17",
             "degree Balling",

units/unit_definitions.hpp

@@ -1162,9 +1162,10 @@ namespace precise {
                     return std::exp(val / 0.5);
                 case 16:  // API Gravity
                     return 141.5 / (val + 131.5);
-                case 17:  // degrees Baume
-                    return (val > 0.0) ? (140.0 / (130.0 + val)) :
-                                         (145.0 / (145.0 - val));
+                case 17:  // degrees Baume Light
+                    return 140.0 / (130.0 + val);
+                case 18:  // degrees Baume Heavy
+                    return 145.0 / (145.0 - val);
                 case 22:  // saffir simpson hurricane wind scale
                 {
                     double out = -0.17613636364;
@@ -1242,9 +1243,10 @@ namespace precise {
                     return 0.5 * (std::log)(val);
                 case 16:  // API Gravity
                     return 141.5 / (val)-131.5;
-                case 17:  // degree Baume
-                    return (val > 1.0) ? (145.0 * (1.0 - 1 / val)) :
-                                         (140.0 / val - 130);
+                case 17:  // degree Baume Light
+                    return 140.0 / val - 130;
+                case 18:  // degree Baume Heavy
+                    return 145.0 * (1.0 - 1.0 / val);
                 case 22:  // saffir simpson hurricane scale from wind speed
                 {  // using horners method on polynomial approximation of
                    // saffir-simpson wind speed scale
@@ -1412,8 +1414,10 @@ namespace precise {
         // for measuring density in liquids(mainly petroleum products)
         constexpr precise_unit degreeAPI =
             precise_unit(custom::equation_unit(16)) * g / mL;
-        constexpr precise_unit degreeBaume =
+        constexpr precise_unit degreeBaumeLight =
             precise_unit(custom::equation_unit(17)) * g / mL;
+        constexpr precise_unit degreeBaumeHeavy =
+            precise_unit(custom::equation_unit(18)) * g / mL;
     }  // namespace special
 
     namespace other {

units/units.cpp

@@ -2590,6 +2590,12 @@ static const std::unordered_map<std::string, std::string> modifiers{
     ckpair{"US dry", "US"},
     ckpair{"USA", "US"},
     ckpair{"USstatute", "US"},
+    ckpair{"USheavy", "heavy"},
+    ckpair{"USlight", "light"},
+    ckpair{"Heavy", "heavy"},
+    ckpair{"Light", "light"},
+    ckpair{"heavy", "heavy"},
+    ckpair{"light", "light"},
     ckpair{"US statute", "US"},
     ckpair{"statutory", "US"},
     ckpair{"statute", "US"},

units/units_conversion_maps.hpp

@@ -722,14 +722,14 @@ UNITS_CPP14_CONSTEXPR_OBJECT std::array<
         {"\xB0"
          "API",
          precise::special::degreeAPI},  // latin-1 degree
-        {"degBaume", precise::special::degreeBaume},
+        {"degBaume", precise::special::degreeBaumeLight},
         {u8"\u00B0Baume",
-         precise::special::degreeBaume},  // unicode degree symbol
+         precise::special::degreeBaumeLight},  // unicode degree symbol
         {"\xB0"
          "Baume",
-         precise::special::degreeBaume},  // latin-1 degree
-        {"degBaume(USheavy)", precise::special::degreeBaume},
-        {"degBaume(USlight)", precise::special::degreeBaume},
+         precise::special::degreeBaumeLight},  // latin-1 degree
+        {"degBaume_heavy", precise::special::degreeBaumeHeavy},
+        {"degBaume_light", precise::special::degreeBaumeLight},
         {"degBalling",
          {1.0, precise::generate_custom_unit(109), commodities::sugar}},
         {"degBrix",