Fix and tests for issue #705 (#731)

boostorg · Jan 5, 2022 · e8edbb9 · e8edbb9
1 parent 60d54e5
commit e8edbb9
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Showing 3 changed files with 31 additions and 1 deletion.
diff --git a/include/boost/math/special_functions/powm1.hpp b/include/boost/math/special_functions/powm1.hpp
@@ -40,7 +40,7 @@ inline T powm1_imp(const T x, const T y, const Policy& pol)
          // fall through....
       }
    }
-   else
+   else if (x < 0)
    {
       // y had better be an integer:
       if (boost::math::trunc(y) != y)

diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
@@ -146,6 +146,7 @@ test-suite special_fun :
    [ run ccmath_hypot_test.cpp ../../test/build//boost_unit_test_framework : : : [ requires cxx17_if_constexpr ] ]
    [ run log1p_expm1_test.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework  ]
    [ run powm1_sqrtp1m1_test.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework  ]
+   [ run git_issue_705.cpp ../../test/build//boost_unit_test_framework  ]
    [ run special_functions_test.cpp ../../test/build//boost_unit_test_framework  ]
    [ run test_airy.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework  ]
    [ run test_bessel_j.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework  ]

diff --git a/test/git_issue_705.cpp b/test/git_issue_705.cpp
@@ -0,0 +1,29 @@
+// Copyright Matt Borland, 2022
+// Use, modification and distribution are subject to the
+// Boost Software License, Version 1.0. (See accompanying file
+// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include "math_unit_test.hpp"
+#include <cmath>
+#include <boost/math/special_functions/powm1.hpp>
+
+template <typename T>
+void test()
+{
+    CHECK_EQUAL(std::pow(T(0), T(2)) - 1, boost::math::powm1(T(0), T(2)));
+    CHECK_EQUAL(std::pow(T(0), T(-2)) - 1, boost::math::powm1(T(0), T(-2)));
+    CHECK_EQUAL(std::pow(T(0), T(0.1)) - 1, boost::math::powm1(T(0), T(0.1)));
+    CHECK_EQUAL(std::pow(T(0), T(-0.1)) - 1, boost::math::powm1(T(0), T(-0.1)));
+}
+
+int main()
+{
+    test<float>();
+    test<double>();
+
+    #ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
+    test<long double>();
+    #endif
+
+    return boost::math::test::report_errors();
+}