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Fix for issue 845 (#846)

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* Fix for issue 845

Avoid division by zero in special cases
This commit is contained in:
Matt Borland
2022-10-17 13:52:56 -07:00
committed by GitHub
parent 9da3a0abb0
commit dfdb50caca
3 changed files with 71 additions and 2 deletions
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13
include/boost/math/distributions/non_central_beta.hpp
View File

@@ -86,7 +86,12 @@ namespace boost
}
pois *= i / l2;
beta += xterm;
xterm *= (a + i - 1) / (x * (a + b + i - 2));
if (a + b + i != 2)
{
xterm *= (a + i - 1) / (x * (a + b + i - 2));
}
last_term = term;
}
for(int i = k + 1; ; ++i)
@@ -555,7 +560,11 @@ namespace boost
break;
}
pois *= i / l2;
beta *= (a + i - 1) / (x * (a + i + b - 1));
if (a + b + i != 1)
{
beta *= (a + i - 1) / (x * (a + i + b - 1));
}
}
for(int i = k + 1; ; ++i)
{

1
test/Jamfile.v2
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@@ -891,6 +891,7 @@ test-suite distribution_tests :
[ compile test_dist_deduction_guides.cpp : [ requires cpp_deduction_guides cpp_variadic_templates ] ]
[ run git_issue_800.cpp ../../test/build//boost_unit_test_framework ]
[ run git_issue_845.cpp ../../test/build//boost_unit_test_framework ]
;
test-suite mp :

59
test/git_issue_845.cpp Normal file
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@@ -0,0 +1,59 @@
// Copyright Matt Borland, 2022
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <cfenv>
#include <iostream>
#include <boost/math/distributions/non_central_f.hpp>
#include "math_unit_test.hpp"
#pragma STDC FENV_ACCESS ON
int main()
{
auto ncf1 = boost::math::non_central_f(2, 2, 2);
const auto cdf1 = boost::math::cdf(ncf1, 0.05);
// https://www.wolframalpha.com/input?i=N%5BCdf%28NonCentralFRatioDistribution%282%2C2%2C2%29%2C+0.05%29%2C+15%5D
CHECK_ULP_CLOSE(cdf1, 0.0183724431823392, 15);
if (std::fetestexcept(FE_INVALID) || std::fetestexcept(FE_DIVBYZERO))
{
return 1;
}
auto ncf2 = boost::math::non_central_f(1, 3, 2);
const auto cdf2 = boost::math::cdf(ncf2, 0.05);
// https://www.wolframalpha.com/input?i=N%5BCdf%28NonCentralFRatioDistribution%281%2C3%2C2%29%2C+0.05%29%2C+15%5D
CHECK_ULP_CLOSE(cdf2, 0.0611253404710995, 15);
if (std::fetestexcept(FE_INVALID) || std::fetestexcept(FE_DIVBYZERO))
{
return 2;
}
auto ncf3 = boost::math::non_central_f(1, 1, 2);
const auto cdf3 = boost::math::cdf(ncf3, 0.05);
// https://www.wolframalpha.com/input?i=N%5BCdf%28NonCentralFRatioDistribution%281%2C1%2C2%29%2C+0.05%29%2C+15%5D
CHECK_ULP_CLOSE(cdf3, 0.0531991288870987, 15);
if (std::fetestexcept(FE_INVALID) || std::fetestexcept(FE_DIVBYZERO))
{
return 3;
}
const auto pdf3 = boost::math::pdf(ncf3, 0.05);
// https://www.wolframalpha.com/input?i=N%5BPdf%28NonCentralFRatioDistribution%281%2C1%2C2%29%2C+0.05%29%2C+15%5D
CHECK_ULP_CLOSE(pdf3, 0.547785080683644, 15);
if (std::fetestexcept(FE_INVALID) || std::fetestexcept(FE_DIVBYZERO))
{
return 4;
}
return boost::math::test::report_errors();
}