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From: "brchrisman at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug math/27617] New: tgamma integer wrapping results in inaccurate
 result.
Date: Sun, 21 Mar 2021 00:26:02 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D27617

            Bug ID: 27617
           Summary: tgamma integer wrapping results in inaccurate result.
           Product: glibc
           Version: 2.32
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: math
          Assignee: unassigned at sourceware dot org
          Reporter: brchrisman at gmail dot com
  Target Milestone: ---

For integer parameters greater than 6, tgamma(n+1) !=3D n!
(note: 719 and beyond are off-by-one, while the real parameter at the bottom
results in 720)

#include <iostream>
#include <cmath>
using namespace std;
int main(void)
{
        uint64_t foo;
        for(int i=3D0; i < 10; i++)
        {
                foo =3D tgamma(i);
                cout << foo << "\n";
        }
        cout << tgamma(7.0) << "\n";
}

0
1
1
2
6
24
120
719
5039
40319
720

--=20
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