Add a few more tgamma at 128 bit tests

Author: ckormanyos

test/test_tgamma.cpp

@@ -316,6 +316,64 @@ namespace local
 
     return result_is_ok;
   }
+
+  auto test_tgamma_128(const int tol_factor) -> bool
+  {
+    using decimal_type = boost::decimal::decimal128;
+
+    using str_ctrl_array_type = std::array<const char*, 9U>;
+
+    const str_ctrl_array_type ctrl_strings =
+    {{
+       // Table[N[Gamma[(100 n + 10 n + 1)/100], 33], {n, 1, 9, 1}]
+       "0.947395504039301942134227647281424",
+       "1.10784755653406415338349971053114",
+       "2.71139823924390323650711692085896",
+       "10.2754040920152050479188001843206",
+       "53.1934282525008207389522379291890",
+       "350.998609824200588801455504140098",
+       "2825.09453680418713613816084109635",
+       "26903.6719467497675679082571845063",
+       "296439.082102472192334520537379648"
+    }};
+
+    std::array<decimal_type, std::tuple_size<str_ctrl_array_type>::value> tg_values   { };
+    std::array<decimal_type, std::tuple_size<str_ctrl_array_type>::value> ctrl_values { };
+
+    int n { 1 };
+
+    bool result_is_ok { true };
+
+    const decimal_type my_tol { std::numeric_limits<decimal_type>::epsilon() * static_cast<decimal_type>(tol_factor) };
+
+    for(auto i = static_cast<std::size_t>(UINT8_C(0)); i < std::tuple_size<str_ctrl_array_type>::value; ++i)
+    {
+      decimal_type x_arg =
+        decimal_type
+        {
+            decimal_type { 1, 2 } * n
+          + decimal_type { 1, 1 } * n
+          + 1
+        }
+        / decimal_type { 1, 2 };
+
+        ++n;
+
+        tg_values[i] = tgamma(x_arg);
+
+        static_cast<void>
+        (
+          from_chars(ctrl_strings[i], ctrl_strings[i] + std::strlen(ctrl_strings[i]), ctrl_values[i])
+        );
+
+      const auto result_tgamma_is_ok = is_close_fraction(tg_values[i], ctrl_values[i], my_tol);
+
+      result_is_ok = (result_tgamma_is_ok && result_is_ok);
+    }
+
+    return result_is_ok;
+  }
+
 } // namespace local
 
 auto main() -> int
@@ -372,28 +430,11 @@ auto main() -> int
   }
 
   {
-    using decimal_type = boost::decimal::decimal128;
-
-    const char str_ctrl[] = "12.64819265438397922113369900828315";
+    const auto result_tgamma128_is_ok   = local::test_tgamma_128(1000000);
 
-    const decimal_type x = decimal_type { 456, -2 };
+    BOOST_TEST(result_tgamma128_is_ok);
 
-    // N[Gamma[456/100], 34]
-    // 12.64819265438397922113369900828315
-    const auto tg = tgamma(x);
-
-    decimal_type ctrl { };
-
-    from_chars(str_ctrl, str_ctrl + std::strlen(str_ctrl), ctrl);
-
-    //std::cout << std::setprecision(34) << tg   << std::endl;
-    //std::cout << std::setprecision(34) << ctrl << std::endl;
-
-    const auto result_tgamma_is_ok   = local::is_close_fraction(tg, ctrl, std::numeric_limits<decimal_type>::epsilon() * 1000000);
-
-    BOOST_TEST(result_tgamma_is_ok);
-
-    result_is_ok = (result_tgamma_is_ok && result_is_ok);
+    result_is_ok = (result_tgamma128_is_ok && result_is_ok);
   }
 
   result_is_ok = ((boost::report_errors() == 0) && result_is_ok);