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<p class="MsoNormal">Back in 2010, the algorithm for this function was updated, adding the following clause:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> if (__x < 10)<o:p></o:p></p>
<p class="MsoNormal"> {<o:p></o:p></p>
<p class="MsoNormal"> const result_type __fac[] = {1, 1, 2, 6, 24, 120, 720, 5040,<o:p></o:p></p>
<p class="MsoNormal"> 40320, 362880};<o:p></o:p></p>
<p class="MsoNormal"> __px = -__pr.__mean_;<o:p></o:p></p>
<p class="MsoNormal"> __py = _VSTD::pow(__pr.__mean_, (double)__x) / __fac[__x];<o:p></o:p></p>
<p class="MsoNormal"> }<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In this case, result_type is the single template parameter to the instantiation of std::poisson_distribution.<o:p></o:p></p>
<p class="MsoNormal">In the case that std::poisson_distribution is instantiated with a 16-bit signed integral type, __fac[8] and __fac[9] are out of range of result_type, and are truncated or result in a change of sign.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Since the only use of __fac is as an operand to a double-precision floating point division, would it not make sense to instead declare it ‘double’ instead of ‘result_type’, and then modify the values populating it to be doubles?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal">J.B. Nagurne<o:p></o:p></p>
<p class="MsoNormal">Code Generation<o:p></o:p></p>
<p class="MsoNormal">Texas Instruments<o:p></o:p></p>
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