cas/xcas implementation of Geometric PDF

[parisse]

Code:


  // geometric_cdf(p,k)=1-(1-p)^k
...
  // k=geometric_icdf(p,P) if 1-(1-p)^k>=P hence 
  gen geometric_icdf(const gen & p,const gen & P,GIAC_CONTEXT){
    return _ceil(ln(1-P,contextptr)/ln(1-p,contextptr),contextptr);
  }

There is no check on k being an integer for geometric_cdf since it's not necessary to compute the expression.