[PATCH] PR libstdc++/83833 fix chi_squared_distribution::param(const param&)
Jonathan Wakely
jwakely@redhat.com
Mon Jan 15 20:18:00 GMT 2018
The chi_squared_distribution::param(const param&) function should also
update the parameters of the gamma_distribution member.
PR libstdc++/83833
* include/bits/random.h (chi_squared_distribution::param): Update
gamma distribution parameter.
* testsuite/26_numerics/random/chi_squared_distribution/83833.cc: New
test.
Tested powerpc64le-linux, committed to trunk.
(I know this is not a regression, but it's a small fix, and I also
plan to apply it on the branches).
-------------- next part --------------
commit 23aebfd022adb918bbe7e1c12efc00020a4299f6
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Mon Jan 15 17:16:07 2018 +0000
PR libstdc++/83833 fix chi_squared_distribution::param(const param&)
PR libstdc++/83833
* include/bits/random.h (chi_squared_distribution::param): Update
gamma distribution parameter.
* testsuite/26_numerics/random/chi_squared_distribution/83833.cc: New
test.
diff --git a/libstdc++-v3/include/bits/random.h b/libstdc++-v3/include/bits/random.h
index 655ee1df6d6..f812bbf18b1 100644
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -2643,7 +2643,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*/
void
param(const param_type& __param)
- { _M_param = __param; }
+ {
+ _M_param = __param;
+ typedef typename std::gamma_distribution<result_type>::param_type
+ param_type;
+ _M_gd.param(param_type{__param.n() / 2});
+ }
/**
* @brief Returns the greatest lower bound value of the distribution.
diff --git a/libstdc++-v3/testsuite/26_numerics/random/chi_squared_distribution/83833.cc b/libstdc++-v3/testsuite/26_numerics/random/chi_squared_distribution/83833.cc
new file mode 100644
index 00000000000..01667635b41
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/random/chi_squared_distribution/83833.cc
@@ -0,0 +1,39 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-do run { target c++11 } }
+
+#include <random>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+ std::default_random_engine r1, r2;
+ using chi = std::chi_squared_distribution<double>;
+ chi::param_type p(5);
+ chi d1(p);
+ chi d2;
+ d2.param(p);
+ VERIFY( d1(r1) == d2(r2) ); // PR libstdc++/83833
+}
+
+int
+main()
+{
+ test01();
+}
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