This patch doesn't treat dummies well, but I guess that can be fixed
later:
In [6]: a_d = Symbol('a',dummy=True)
In [7]: a = Symbol('alpha',dummy=True)
In [8]: f = 2*a*a_d*x
In [9]: f
Out[9]: 2*x*a*alpha
In [10]: f(a=2)
Out[10]: 2*x*a*alpha
In [11]: f(a_d=2)
Out[11]: 2*x*a*alpha
In [12]: f(alpha=2)
Out[12]: 2*x*a*alpha
In [13]: a = Symbol('alpha')
In [14]: f = 2*a*a_d*x
In [15]: f(alpha=2)
Out[15]: 4*x*a
In [16]: f(a=2)
Out[16]: 2*alpha*x*a
On Nov 19, 10:42 pm, Lance Larsen <[EMAIL PROTECTED]> wrote:
> For what it is worth, I fixed the errors in the last patch submitted.
> Looks like a previous patch has already been applied in main
> repository though. I used a different method to export this patch. I
> used the command 'hg qdiff' to get the diff info and stole the patch
> header from my previously submitted patch. Don't know if this causes
> problems. 'hg email' was complaining about my parent repository setup
> and I didn't have time to debug this so I tried a workaround.
>
> -Lance
>
> # HG changeset patch
> # User "Lance Larsen <[EMAIL PROTECTED]>"
> # Date 1226946818 25200
> # Node ID 5699c540c62b31ddf3c96e07fae6fe64cf10eb1e
> # Parent d1019a5c66d12d524fe64359c1bd8054cab0cfa9
> Substitution syntax extension - implements f.subs(x=1,y=2) and
> shorthand syntax f(x=1,y=2).
>
> diff -r dab6435e04fd sympy/core/basic.py
> --- a/sympy/core/basic.py Thu Nov 06 23:12:01 2008 +0100
> +++ b/sympy/core/basic.py Wed Nov 19 14:33:25 2008 -0700
> @@ -899,26 +899,43 @@
> """
> return self
>
> - def subs(self, *args):
> + def subs(self, *args, **kwargs):
> """
> Substitutes an expression.
>
> Calls either _subs_old_new, _subs_dict or _subs_list
> depending
> - if you give it two arguments (old, new), a dictionary or a
> list.
> + if you give it two arguments (old, new), a dictionary, a list
> or
> + pass in named parameters. When named parameters are passed
> in,
> + these are converted to a dictionary and _subs_dict is called.
>
> Examples:
>
> >>> from sympy import *
> >>> x,y = symbols('xy')
> - >>> (1+x*y).subs(x, pi)
> - 1 + pi*y
> + >>> (1+x*y).subs(x=pi, y=2)
> + 1 + 2*pi
> >>> (1+x*y).subs({x:pi, y:2})
> 1 + 2*pi
> >>> (1+x*y).subs([(x,pi), (y,2)])
> 1 + 2*pi
> + >>> (1+x*y).subs(x, pi)
> + 1 + pi*y
> +
> + Subs can be called implicitly as well as shown in the
> following
> + examples:
> +
> + >>> f = 1+x*y
> + >>> f(x=pi, y=2)
> + 1 + 2*pi
> + >>> f({x:pi, y:2})
> + 1 + 2*pi
> + >>> f([(x,pi), (y,2)])
> + 1 + 2*pi
> + >>> f(x, pi)
> + 1 + pi*y
>
> """
> - if len(args) == 1:
> + if len(args) == 1 and len(kwargs) == 0:
> sequence = args[0]
> if isinstance(sequence, dict):
> return self._subs_dict(sequence)
> @@ -926,9 +943,11 @@
> return self._subs_list(sequence)
> else:
> raise TypeError("Not an iterable container")
> - elif len(args) == 2:
> + elif len(args) == 2 and len(kwargs) == 0:
> old, new = args
> return self._subs_old_new(old, new)
> + elif len(args) == 0 and len(kwargs) > 0:
> + return self._subs_dict(kwargs)
> else:
Why do we use Exception instead of ValueError or TypeError?
> raise Exception("subs accept either 1 or 2 arguments")
>
> @@ -1935,9 +1954,25 @@
> from sympy.integrals import integrate
> return integrate(self, *args, **kwargs)
>
> - #XXX fix the removeme
> - def __call__(self, *args, **removeme):
> - return Function(self[0])(*args)
> + def __call__(self, *args, **kwargs):
> + """Alias for calling the subs function. Substitution using
> two parameters
> + (i.e. f(x,3)) and list of pairs (f([(x,3),(y,2)])) is not
> supported
> + because the notation may be confusing to sympy users.
> +
> + Examples:
> +
> + >>> from sympy import *
> + >>> x,y = symbols('xy')
> + >>> f = 1+x*y
> + >>> f(x=pi,y=2)
> + 1 + 2*pi
> + >>> f({x:pi, y:2})
> + 1 + 2*pi
> + """
> + if len(args) > 1 or (len(args) == 1 and isinstance(args[0],
> (list, tuple))):
> + sequence = args[0]
> + raise Exception("Unsupported syntax. Pass a dictionary or
> name=value pairs.")
> + return self.subs(*args, **kwargs)
>
> def __float__(self):
> result = self.evalf()
> diff -r dab6435e04fd sympy/core/tests/test_subs.py
> --- a/sympy/core/tests/test_subs.py Thu Nov 06 23:12:01 2008 +0100
> +++ b/sympy/core/tests/test_subs.py Wed Nov 19 14:33:25 2008 -0700
> @@ -169,3 +169,14 @@
> assert (f(x,y)).subs(f,sin) == f(x,y)
> assert (sin(x)+atan2(x,y)).subs([[atan2,f],[sin,g]]) == f(x,y) + g
> (x)
> assert (g(f(x+y, x))).subs([[f, l], [g, exp]]) == exp(x + sin(x +
> y))
> +
> +def test_subs_call_syntax():
> + a, b, x, y, p, q = map(Symbol, "abxypq")
> + f = 2*a*x+3*b*y
> + assert f.subs(x=1, y=2) == 2*a + 6*b
> +
> +def test_implicit_subs_call_syntax():
> + a, b, x, y, p, q = map(Symbol, 'abxypq')
> + f = 2*a*x + 3*b*y
> + assert f(x=1, y=2) == 2*a + 6*b
> + assert f({a*x:p,b*y:q}) == 2*p + 3*q
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