functions in gammp.i - g

    gammp(a, x)  
 or gammp(a, x, q, lg)  


  return P(a,x) = int[0 to x]{ du * u^(a-1)*exp(-u) } / gamma(a)  
  optionally return Q(a,x) = 1-P(a,x) and ln(gamma(a))  
  
  Note that erf(x)=gammp(0.5,x^2) and erfc(x)=gammq(0.5,x^2)  
  Also P(chi2|nu)=gammp(0.5*nu,0.5*chi2)  
   and Q(chi2|nu)=gammq(0.5*nu,0.5*chi2)  
  are the probabilities that an observed chi-square be less than  
  or greater than (P or Q) chi2 when there are nu degrees of freedom  
  (terms in the chi-square sum).  
  
   Interpreted function, defined at i/gammp.i   line 14  

    gammq(a, x)  
 or gammq(a, x, p, lg)  


  return Q(a,x) = 1 - int[0 to x]{ du * u^(a-1)*exp(-u) } / gamma(a)  
  optionally return P(a,x) = 1-Q(a,x) and ln(gamma(a))  
  
  Note that erf(x)=gammp(0.5,x^2) and erfc(x)=gammq(0.5,x^2)  
  Also P(chi2|nu)=gammp(0.5*nu,0.5*chi2)  
   and Q(chi2|nu)=gammq(0.5*nu,0.5*chi2)  
  are the probabilities that an observed chi-square be less than  
  or greater than (P or Q) chi2 when there are nu degrees of freedom  
  (terms in the chi-square sum).  
  
   Interpreted function, defined at i/gammp.i   line 50