Help with sympy, please

[Dick Moores]

At 05:24 PM 11/18/2007, Fredrik Johansson wrote:
>On Nov 19, 2007 2:03 AM, Dick Moores <rdm at rcblue.com> wrote:
> > At 04:26 PM 11/18/2007, Fredrik Johansson wrote:
> > >On Nov 19, 2007 1:05 AM, Dick Moores <rdm at rcblue.com> wrote:
> > >Hi Dick, I recognize you from python-list, where you had a question
> > >about mpmath.
> > >
> > >Your code still won't work if you convert the numbers to Floats
> > >because the Float type in sympy.numerics does not implement ** for
> > >fractional numbers. You could use the exp function in
> > >sympy.numerics.functions instead to compute e**x.
> >
> > Thanks, Fredrik, but I get the same error using either exp or power:
> > ============================
> > from __future__ import division
> > from sympy import *
> > from sympy import Rational as R
> > from sympy.numerics import *
> > from sympy.numerics.functions import power, exp
> >
> > prec = 50
> > Float.setdps(prec)
> > e = evalf(E)
> > n = 1
> > m = n + 1
> > k = 0
> > n = evalf(R(n,1))
> > m = evalf(R(m,1))
> > prod = evalf(R(1,1))
> > prec = 50
> > Float.setdps(prec)
> > e = evalf(E)
> > n = 1
> > k = 0
> > prod = evalf(R(1,1))
> > while k < 1000:
> >       k += 1
> >       n = evalf(R(n,1))
> >       term = (exp(1/n))/(exp(1/(n+1)))
> >       prod *= term
> >       n += 2
> > print prod, term
> > =============================
> > term = (exp(1/n))/(exp(1/(n+1)))
> > TypeError: unsupported operand type(s) for /: 'int' and 'Float'
> >
> > And also if I use sympy.numerics.functions.power in that line, as
> > term = power(e,(1/n))/power(e,(1/(n+1)))
> >
> > I get:
> >
> > term = power(e,(1/n))/power(e,(1/(n+1)))
> > TypeError: unsupported operand type(s) for /: 'int' and 'Float'
>
>Try not using "from __future__ import division".

Didn't help.


>Also,
>
>      n = evalf(R(n,1))
>
>won't work, because the arguments to Rational must be ints.

But both n and 1 are ints, aren't they?

Anyway, you've by now seen my new success with mpmath. I'll abandon 
syspy for the time being.

Dick