On Feb 28, 3:53 pm, "John Machin" <[EMAIL PROTECTED]> wrote: > On Feb 28, 10:38 pm, "BartOgryczak" <[EMAIL PROTECTED]> wrote: > > > [1] eg. consider calculating interests rate, which often is defined as > > math.pow(anualRate,days/365.0). > > In what jurisdiction for what types of transactions? I would have > thought/hoped that the likelihood that any law, standard or procedure > manual would define an interest calculation in terms of the C stdlib > would be somewhere in the region of math.pow(epsilon, HUGE), not > "often".
YPB? Have you ever heard of real-time systems? > More importantly, the formula you give is dead wrong. The correct > formula for converting an annual rate of interest to the rate of > interest to be used for n days (on the basis of 365 days per year) is: > > (1 + annual_rate) ** (n / 365.0) - 1.0 > or > math.pow(1 + annual_rate, n / 365.0) - 1.0 > if you prefer. YPB? Anyone with half a brain knows, that you can either express rate as 0.07 and do all those ridiculous conversions above, or express it as 1.07 and apply it directly. > > BTW, math.* functions do not return Decimals. > > For which Bell Labs be praised, but what's your point? That Decimal is useless, for anything but invoices. -- http://mail.python.org/mailman/listinfo/python-list