Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.python > #106144
| Newsgroups | comp.lang.python |
|---|---|
| Date | 2016-03-31 03:57 -0700 |
| References | <733f5f0d-9b4e-4023-897b-e1f2730c39cb@googlegroups.com> <56fbcd01$0$1599$c3e8da3$5496439d@news.astraweb.com> <99b7cf43-50ff-4de7-8de0-e324658682bf@googlegroups.com> <56fbf7e7$0$1591$c3e8da3$5496439d@news.astraweb.com> |
| Message-ID | <244e1277-e105-4419-a449-7f2012c6d78e@googlegroups.com> (permalink) |
| Subject | Re: sympy |
| From | Poul Riis <priisdk@gmail.com> |
Den onsdag den 30. marts 2016 kl. 17.59.49 UTC+2 skrev Steven D'Aprano:
> On Thu, 31 Mar 2016 02:23 am, Poul Riis wrote:
>
> > What I intend to do is to let sympy find the derivative of some
> > welldefined function and next define the foundation derivative as a normal
> > function so that I can calculate numerical values or even make a graph.
>
>
> I'm glad you explained what you *actually* wanted, because I was going to
> guess that you wanted to evaluate the derivative at x = 3:
>
>
> py> ftext.evalf(subs={x:3})
> -0.0600000000000000
>
>
>
> --
> Steven
... However, the sympy way seems to be about 70 times slower than using the derivative calculated 'by hand' (try the example below).
Can it be done in a more efficient way?
Poul Riis
from sympy import *
from time import *
x=Symbol('x')
ftext=diff(sin(x),x)
def fmsympy(t):
return ftext.evalf(subs={x:t})
def fm(t):
return cos(t)
nloop=10000
tstart=time()
# nloop evaluations with sympy
for i in range(0,nloop):
a=fmsympy(1)
dt1=time()-tstart
# nloop evaluations without sympy
tstart=time()
for i in range(0,nloop):
a=fm(1)
dt2=time()-tstart
print(nloop,' evaluations with sympy : dt1 =',dt1)
print(nloop,' evaluations without sympy: dt2 =',dt2)
Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
sympy Poul Riis <priisdk@gmail.com> - 2016-03-30 04:17 -0700
Re: sympy Ben Finney <ben+python@benfinney.id.au> - 2016-03-30 22:29 +1100
Re: sympy Ned Batchelder <ned@nedbatchelder.com> - 2016-03-30 04:39 -0700
Re: sympy Steven D'Aprano <steve@pearwood.info> - 2016-03-30 23:56 +1100
Re: sympy Poul Riis <priisdk@gmail.com> - 2016-03-30 08:23 -0700
Re: sympy Robert Kern <robert.kern@gmail.com> - 2016-03-30 16:29 +0100
Re: sympy Steven D'Aprano <steve@pearwood.info> - 2016-03-31 02:59 +1100
Re: sympy Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-03-31 17:49 +1300
Re: sympy Poul Riis <priisdk@gmail.com> - 2016-03-30 23:51 -0700
Re: sympy Poul Riis <priisdk@gmail.com> - 2016-03-31 03:57 -0700
Re: sympy Peter Otten <__peter__@web.de> - 2016-03-31 16:55 +0200
Re: sympy Chris Angelico <rosuav@gmail.com> - 2016-04-01 04:05 +1100
Re: sympy Peter Otten <__peter__@web.de> - 2016-03-31 19:51 +0200
Re: sympy Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2016-03-31 19:59 +0100
Re: sympy Poul Riis <priisdk@gmail.com> - 2016-03-31 14:33 -0700
Re: sympy Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2016-03-31 23:26 +0100
csiph-web