I should point out that Bharath is using Numpy, so if anyone knows of a solution using that, that will work too.
Aaron Meurer On Jun 1, 2012, at 2:01 AM, Joachim Durchholz <[email protected]> wrote: > Am 01.06.2012 09:45, schrieb Chris Smith: >> On Fri, Jun 1, 2012 at 1:25 PM, Joachim Durchholz<[email protected]> wrote: >>> Am 01.06.2012 09:25, schrieb Chris Smith: >>>> >>>> How about round down and then add your interval width? >>> >>> You'll add a rounding unit if the input value happens to be exact. >>> >> >> Can the interval have zero width? > > It could, but that doesn't affect the outcome - you're working on the upper > bound. > > > If so then, yes, and b could then be >> calculated as >> >> b=(a+10**-3).round(3) if a!=n else a > > Not sure what n is here. > Also, you'd want to add half of the step size to cover the round-down case. > > I'm not sure what Python's rounding mode is. IEEE defines some rounding modes > that won't do what you expect (such as rounding up or down depending on the > parity of the mantissa - I heard that's helpful to improve the stability of > some numeric algorithm, that's why IEEE defines it). > The scary thing here is that C code might actually have changed the rounding > mode. And if you're doing numeric work, I'd expect that some people will > indeed use a C module that does exactly this together with SymPy. > > So my proposal would be to stick with floor() and ceil(). These are > well-defined operations. > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
