.TH "std::poisson_distribution< _IntType, _RealType >" 3cxx "Thu Aug 2 2012" "libstdc++" \" -*- nroff -*-
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.SH NAME
std::poisson_distribution< _IntType, _RealType > \- 
.SH SYNOPSIS
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.PP
.SS "Public Types"

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.RI "typedef _RealType \fBinput_type\fP"
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.RI "typedef _IntType \fBresult_type\fP"
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.SS "Public Member Functions"

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.RI "_RealType \fBmean\fP () const "
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.RI "template<class _UniformRandomNumberGenerator > result_type \fBoperator()\fP (_UniformRandomNumberGenerator &__urng)"
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.RI "\fBpoisson_distribution\fP (const _RealType &__mean=_RealType(1))"
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.RI "void \fBreset\fP ()"
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.SS "Friends"

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.RI "template<typename _IntType1 , typename _RealType1 , typename _CharT , typename _Traits > \fBstd::basic_ostream\fP< _CharT, 
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_Traits > & \fBoperator<<\fP (\fBstd::basic_ostream\fP< _CharT, _Traits > &__os, const \fBpoisson_distribution\fP< _IntType1, _RealType1 > &__x)"
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.RI "template<typename _IntType1 , typename _RealType1 , typename _CharT , typename _Traits > \fBstd::basic_istream\fP< _CharT, 
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_Traits > & \fBoperator>>\fP (\fBstd::basic_istream\fP< _CharT, _Traits > &__is, \fBpoisson_distribution\fP< _IntType1, _RealType1 > &__x)"
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.SH "Detailed Description"
.PP 

.SS "template<typename _IntType = int, typename _RealType = double>class std::poisson_distribution< _IntType, _RealType >"
A discrete Poisson random number distribution\&. 

The formula for the Poisson probability mass function is $ p(i) = \frac{mean^i}{i!} e^{-mean} $ where $ mean $ is the parameter of the distribution\&. 
.PP
Definition at line 1864 of file tr1_impl/random\&.
.SH "Member Function Documentation"
.PP 
.SS "template<typename _IntType = int, typename _RealType = double> _RealType \fBstd::poisson_distribution\fP< _IntType, _RealType >::mean () const\fC [inline]\fP"
Gets the distribution parameter \fCmean\fP\&. 
.PP
Definition at line 1884 of file tr1_impl/random\&.
.SS "template<typename _IntType , typename _RealType > template<class _UniformRandomNumberGenerator > \fBpoisson_distribution\fP< _IntType, _RealType >::result_type \fBstd::poisson_distribution\fP< _IntType, _RealType >::operator() (_UniformRandomNumberGenerator &__urng)"
A rejection algorithm when mean >= 12 and a simple method based upon the multiplication of uniform random variates otherwise\&. NB: The former is available only if _GLIBCXX_USE_C99_MATH_TR1 is defined\&.
.PP
Reference: Devroye, L\&. 'Non-Uniform Random Variates Generation\&.' Springer-Verlag, New York, 1986, Ch\&. X, Sects\&. 3\&.3 & 3\&.4 (+ Errata!)\&. 
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Definition at line 936 of file random\&.tcc\&.
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References std::abs(), std::log(), and std::max()\&.
.SH "Friends And Related Function Documentation"
.PP 
.SS "template<typename _IntType = int, typename _RealType = double> template<typename _IntType1 , typename _RealType1 , typename _CharT , typename _Traits > \fBstd::basic_ostream\fP<_CharT, _Traits>& operator<< (\fBstd::basic_ostream\fP< _CharT, _Traits > &__os, const \fBpoisson_distribution\fP< _IntType1, _RealType1 > &__x)\fC [friend]\fP"
Inserts a poisson_distribution random number distribution \fC__x\fP into the output stream \fC__os\fP\&.
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\fBParameters:\fP
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\fI__os\fP An output stream\&. 
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\fI__x\fP A poisson_distribution random number distribution\&.
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\fBReturns:\fP
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The output stream with the state of \fC__x\fP inserted or in an error state\&. 
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.SS "template<typename _IntType = int, typename _RealType = double> template<typename _IntType1 , typename _RealType1 , typename _CharT , typename _Traits > \fBstd::basic_istream\fP<_CharT, _Traits>& operator>> (\fBstd::basic_istream\fP< _CharT, _Traits > &__is, \fBpoisson_distribution\fP< _IntType1, _RealType1 > &__x)\fC [friend]\fP"
Extracts a poisson_distribution random number distribution \fC__x\fP from the input stream \fC__is\fP\&.
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\fBParameters:\fP
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\fI__is\fP An input stream\&. 
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\fI__x\fP A poisson_distribution random number generator engine\&.
.RE
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\fBReturns:\fP
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The input stream with \fC__x\fP extracted or in an error state\&. 
.RE
.PP


.SH "Author"
.PP 
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