Comment #13 on issue 1336 by smi...@gmail.com: Arbitrary constant type
http://code.google.com/p/sympy/issues/detail?id=1336
I don't have a special combining symbol but I have a 'model' function that
absorbs all constants except for a specified 'x'. Using it on the examples
of the OP shows that they are all the same:
for ei in e:
... print together(ei), model(together(ei),x)
...
2*x/(c1 + x**2) 2*x/(C0 + x**2)
2*x/(2*c1 + x**2) 2*x/(C0 + x**2)
2*x/(2*c1 + x**2) 2*x/(C0 + x**2)
Here are the docstring examples:
>>> from sympy import model, exp
>>> from sympy.abc import x, y, z
>>> model(y + 3, x)
C0
>>> model(y + 3, x, 'k')
k0
>>> model(x + 3, x)
x + 3
>>> model(x + 3, x, numbers=True)
C0 + x
>>> model(-x + 3, x, numbers=True)
C0 - x
>>> model(x + 3*y, x)
C0 + x
>>> model(x + 3*y, x, 'x')
x + x0
>>> model(exp(x + 3), x)
exp(x + 3)
>>> model(y*exp(x + 3), x)
C0*exp(x)
>>> model(3*exp(y + x), x)
C0*exp(x)
That last examples involving a power in a Mul are going to be the tricky
ones since the __mul__ or __rmul__ routine would have be receiving the
exp() term as one of the args in order to determine that a combined
constant can be created. That being the case, I don't think an Absorber
would be able to do such combinations except in a flatten routine.
see simplify.py in smichr branch csimp; see also the test suite which
covers all lines of the routine.
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