# Coercion problem while defining piecewise function

In a nutshell: I begin by defining the following function:

```
def g(x):
return math.exp(-1/(1 - x^2))
```

which poses no problem. Then, I try to use this function g to define a new function, as follows:

```
f = Piecewise([ [(-.5,.5), 0.44399*g(x)] ])
```

which returns the following error:

```
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
/Applications/sage/<ipython console> in <module>()
/Applications/sage/<ipython console> in g(x)
/Applications/sage/local/lib/python2.6/site-packages/sage/rings/fraction_field_element.so in sage.rings.fraction_field_element.FractionFieldElement.__float__ (sage/rings/fraction_field_element.c:8540)()
/Applications/sage/local/lib/python2.6/site-packages/sage/rings/polynomial/polynomial_element.so in sage.rings.polynomial.polynomial_element.Polynomial.__float__ (sage/rings/polynomial/polynomial_element.c:8243)()
TypeError: cannot coerce nonconstant polynomial to float
-----------
```

I am not sure of what is going wrong here. Any ideas/solutions would be deeply appreciated.

-jl