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Binomial2 Class Reference

Inheritance diagram for Binomial2:

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Collaboration diagram for Binomial2:

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Public Member Functions

 Binomial2 (int nx, Real px)
 ~Binomial2 ()
Real Next ()
ExtReal Mean () const
ExtReal Variance () const

Private Attributes

DiscreteGen * dg

Constructor & Destructor Documentation

Binomial2::Binomial2 (  int  nx,
Real  px
) 
 

Definition at line 451 of file newran.cpp.

References dg, ErrorNoSpace(), ln_gamma(), and Real. 

00452 {
00453    Real qx = 1.0 - px;
00454    Real probs[40];
00455    int k = (int)(nx * px);
00456    probs[k] = exp(ln_gamma(nx+1) - ln_gamma(k+1) - ln_gamma(nx-k+1)
00457       + k * log(px) + (nx-k) * log(qx));
00458    int i;
00459    int m = (nx >= 40) ? 39 : nx;
00460    for (i=k+1; i<=m; i++) probs[i]=probs[i-1] * px * (nx-i+1) / qx / i;
00461    for (i=k-1; i>=0; i--) probs[i]=probs[i+1] * qx * (i+1) / px / (nx-i);
00462    dg = new DiscreteGen(m + 1, probs);
00463    if (!dg) ErrorNoSpace();
00464 }

Binomial2::~Binomial2 (   ) 
 

Definition at line 466 of file newran.cpp.

References dg. 

00466 { delete dg; }

Member Function Documentation

ExtReal Binomial2::Mean (   )  const [inline, virtual]
 

Reimplemented from Random.

Definition at line 108 of file newran.cpp. 

00108 { return dg->Mean(); }

Real Binomial2::Next (   )  [inline, virtual]
 

Reimplemented from Random.

Definition at line 107 of file newran.cpp.

References Real. 

00107 { return dg->Next(); }

ExtReal Binomial2::Variance (   )  const [inline, virtual]
 

Reimplemented from Random.

Definition at line 109 of file newran.cpp. 

00109 { return dg->Variance(); }

Field Documentation

DiscreteGen* Binomial2::dg [private]
 

Definition at line 103 of file newran.cpp.

Referenced by Binomial2(), and ~Binomial2().

The documentation for this class was generated from the following file:
Generated on Fri Dec 5 04:06:15 2003 for Borqueror by doxygen 1.3.3