Expressing a rational function (with polynomials) as a product of rational functions

[Florent Bresson]

Dear all,

I am an absolute beginner with sympy and I would be very grateful for your assistance.
I have an expression of the form: a*b/(c*d) and I want sympy to express it as a/c * b/d (or a/d * b/c, I don't care). Do you have any idea how to get this? I have seen the apart() function, but that's not what I am looking for.

For those who need details, I have to estimate the value of a cdf in R. But the estimation of that value is difficult since it calls for the n-th order derivative of a multivariate rational function obtained from polynomials. Hence, I use the rSymPy library in R to get my derivative and everythings fine until I try to evaluate the resulting function. Indeed the numerator and the denominator of my derivative are so small that sympy fails in evaluating it precisely. This why I want to express my derivative as a product of ratios that can be evaluated independantly before the product is computed.

I hope the exposal is clear. Thanks in advance for the help (I am not a mathematician).

Florent