If you replace name and _name with 0 in your expression and subtract
the result from the initial expression, that will give you the ones
that *do* have name and _name. Then, if you have an Add
(have_name.is_Add) you could count the terms (len(have_name.args)) and
expand the result after replacing _
It sounds ok to me, but try to prioritize your work, in case you don't get
to one because the other is harder than you thought.
Aaron Meurer
On Mar 14, 2013, at 9:58 PM, Manoj Kumar
wrote:
I'd just like to clarify if my post was a bit ambiguous. I would like to
implement both of these in a sing
Thanks for your comments!
@Aaron, I dont see how what you say would work.
@smichr, instead of using Not(x) to represent the complement, i make a new
symbol _x, which does not raise NotImplemented exceptions when calling
expand().
I have an implementation running, the function ignores the coeff
For multiargument functions (including Pow), you could replace the
arguments that depend on x with x and those that don't with a (if there are
more than one of the first type you might use f(x) instead of x). For
example, if you have x**2, use the rule derived from x**a. For x**x, use
f(x)**g(x).
Thank you very much. You have been most helpful.
I wish you a nice weekend.
Kind regards
Patrice
Le vendredi 15 mars 2013 09:42:34 UTC+1, Patrice Haldemann a écrit :
> I recently started to learn Python and I have stumbled over an issue since
> quite a few days.
> How to evaluate a fun
That would be a good idea. Looking at the code, everything has an
_eval_derivative method which should work. My only concern is that, for
instance, in Pow it combines the power, chain, and exponential rules into
one expression.
In any case, most of the code I added was related to printing and
form
> I don't know if it's idiomatic, but one suggestion is to derive the
> derivative rules automatically from diff. At the very least use a fallback
> so it works for functions you don't have rules for.
>
I agree that it'd be unfortunate to rewrite all of the differentiation
logic. Maybe there is a
> If this an "idiomatic" use of strategies then I'll convert the rest of
the code.
There is no idiomatic or agreed upon use of strategies. They're new,
experimental, and used almost exclusively by me.
The only good idea I can push with confidence is that you should strive to
separate your functi
I don't know if it's idiomatic, but one suggestion is to derive the
derivative rules automatically from diff. At the very least use a fallback
so it works for functions you don't have rules for.
Aaron Meurer
On Mar 15, 2013, at 10:42 AM, David Li wrote:
Okay, so I'd just like to make sure I'm u
Maybe use collect() with x and _x and then replace any instance of a
multiple of x + _x with 1.
Aaron Meurer
On Mar 15, 2013, at 7:46 AM, Roderick de Nijs wrote:
Hi, smichr
Unfortunately not, a constraint I have is that if x and _x appear in other
places that do not simplify out, I would like
The first argument to evalf tells it how many decimal places to evaluate
to. You want subs, either the method or the argument to evalf.
Aaron Meurer
On Mar 15, 2013, at 4:17 AM, Patrice Haldemann
wrote:
I recently started to learn Python and I have stumbled over an issue since
quite a few days.
Okay, so I'd just like to make sure I'm using strategies/rules correctly. I
have the gist of the derivative implementation at
https://gist.github.com/lidavidm/5171100.
- The rules convert the function to be differentiated into a namedtuple
corresponding to the derivative rule to be applie
@mrocklin, I wonder if any of the unify tools -- maybe one to "collect
identities" -- might be used for this.
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How are you representing the Not variables? Within a Not? Because you
could find out who is Not-ed and then replace a given Not with a
(1-not_var) and only keep the replacement if it caused terms to
disappear.
>>> eq
a*b*c*x + a*b*c*Not(x) + a*y
>>> eq.atoms(Not)
set([Not(x)])
>>> _.pop().args[0]
Hi, smichr
Unfortunately not, a constraint I have is that if x and _x appear in other
places that do not simplify out, I would like to keep those parts with
their original literals.
El viernes, 15 de marzo de 2013 14:16:05 UTC+1, smichr escribió:
>
> On Fri, Mar 15, 2013 at 6:37 PM, Roderick
This is certainly an important project, however it is also rather
difficult. Moreover, there was some tangential work on sparse matrices
(and maybe symbolic matrix expressions) that must somehow be combined
in a coherent module.
Most importantly, there is some work done on that by Mateusz Paprocki
On Fri, Mar 15, 2013 at 6:37 PM, Roderick de Nijs wrote:
> I have boolean variables that can be negated or not, so _x=1-x, in a
> sum-of-monomials type of expression. Of course, the regular and negated
> literals are treated as different symbols in sympy.
>
> I would like to do the simplificatio
I have boolean variables that can be negated or not, so _x=1-x, in a
sum-of-monomials type of expression. Of course, the regular and negated
literals are treated as different symbols in sympy.
I would like to do the simplification:
a*b*c*x + a*b*c*_x + other terms = a*b*c
a*b*c*x - a*b*c*_x
Hi,
My name is Saurabh Jha. I am a third year student at an Indian
University. My major is Computer Science and Engineering. I am
interested in Google Summer of Code 2013 and more specifically want to
work on matrix module of sympy. I saw the ideas list and found two
points concerned with rewriti
Oops, I see I got the decimal point wrong, but you get the idea. Also
note that if you use floats you will get a Float (SymPy's version of
the float) automatically, but if you use integers or Rationals, you
will not:
>>> h.subs(x, 2)
cos(2)
>>> _.n()
-0.416146836547142
>>> h.subs(x, S(1)/2)
cos(1/
On Fri, Mar 15, 2013 at 2:27 PM, Patrice Haldemann
wrote:
> I recently started to learn Python and I have stumbled over an issue since
> quite a few days.
> How to evaluate a function at let say x=2.
>
> example
> h=diff(sin(x))
> print(h(2.))
> =cos(x)
The subs method will substitute one or mor
I recently started to learn Python and I have stumbled over an issue since
quite a few days.
How to evaluate a function at let say x=2.
example
h=diff(sin(x))
print(h(2.))
=cos(x)
or
print (N(h(x),2.)
=cos(x)
or
print (h(x).evalf(2.))
=cos (x)
but never the value of cos(2.)
Coul
I won't be available till Tuesday (19th March); going on a field trip. In
the meanwhile, please keep posting ideas/suggestions/problems if any.
Thanks.
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