Defining arbitrary functions

[benjamin]

Hi there!

I am trying to create list of N arbitrary functions of the next form :

x is list of symbols [x_1,x_2,.....,x_M]

f is list of functions [f_1,f_2,.....,f_N]

and every function f_i is a multivariable function of all symbols (x_1,x_2,.....x_M)

NOTE: i just wrote arbitrary M and N but in my calculations they are specified integers.

[benjamin]

This is example

from sympy import Symbol,Function

x1=Symbol ('x1')
x2=Symbol ('x2')
x3=Symbol ('x3')

f1=Function ('f1')
f2=Function ('f2')
f3=Function ('f3')

X=[]
X.append(x1)
X.append(x2)
X.append(x3)

F=[]
F.append(f1(x1,x2,x3))
F.append(f2(x1,x2,x3))
F.append(f3(x1,x2,x3))

is there any smarter way to do it?
thank you

[Jason Moore]

You could use list comprehensions and argument expansion (*):

x = symbols('x1, x2, x3')

functions = [Function(name) for name in ['f1', 'f2', 'f3]]

F = [f(*x) for f in functions]

Jason
moorepants.info
+01 530-601-9791

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[Aaron Meurer]

Also take a look at the numbered_symbols function.

[benjamin]

Thank you guys a lot.

Is there something like numbered_Functions function?

[Christophe Bal]

Hello,

following the advice of Aaron, here is a more generic way to do that.

=== CODE ===

from sympy import *

variables = [

    x for x, _ in zip(

        numbered_symbols(prefix = 'x', start = 1), 

        range(1,4)

    )

]

functions = [

    f for f, _ in zip(

        numbered_symbols(prefix = 'f', cls = Function, start = 1), 

        range(1,4)

    )

]

F = [f(*variables) for f in functions]

2013/12/24 benjamin <benjami...@gmail.com>

Thank you guys a lot.

Is there something like numbered_Functions function?

--

[Aaron Meurer]

Just set the cls parameter in numbered_symbols to Function.

Aaron Meurer

On Tue, Dec 24, 2013 at 1:56 AM, benjamin <benjami...@gmail.com> wrote:
> Thank you guys a lot.
>
> Is there something like numbered_Functions function?
>

[Benjamin Mesić]

Exactly what i was looking for, thank you all.

Benjamin

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