def survival ( value = t , lam = lam , f = failure ) : return sum ( f * log ( lam ) - lam * value )
logistic regression overflow python
Exponential survival likelihood accounting for censoring
def survival(value=t, lam=lam, f=failure):
    """Exponential survival likelihood, accounting for censoring"""
    return sum(f * log(lam) - lam * value)