3 ///////////////////////////////////////////////////////////////////////////
5 // Various mathematical tools which may be very convenient while
6 // performing physics analysis.
8 // Example : Probability of a Chi-squared value
12 // Float_t chi2=20 ; // The chi-squared value
13 // Int_t ndf=12; // The number of degrees of freedom
14 // Float_t p=M.Prob(chi2,ndf); // The probability that at least a Chi-squared
15 // // value of chi2 will be observed, even for a
18 //--- NvE 14-nov-1998 UU-SAP Utrecht
19 ///////////////////////////////////////////////////////////////////////////
26 class AliMath : public TObject
29 AliMath(); // Default constructor
30 ~AliMath(); // Destructor
31 Float_t Gamma(Float_t z); // Standard gamma function Gamma(z)
32 Float_t Gamma(Float_t a,Float_t x); // Incomplete gamma function P(a,x)
33 Float_t LnGamma(Float_t z); // Compute ln[Gamma(z)]
34 Float_t Erf(Float_t x); // Error function erf(x)
35 Float_t Erfc(Float_t x); // Complementary error function erfc(x)
36 Float_t Prob(Float_t chi2,Int_t ndf); // Compute Chi-squared probability
39 Float_t GamSer(Float_t a,Float_t x); // Compute P(a,x) via serial representation
40 Float_t GamCf(Float_t a,Float_t x); // Compute P(a,x) via continued fractions
42 ClassDef(AliMath,1) // Class definition to enable ROOT I/O