Plotting a Piecewise function fails. I've pasted the markdown from my
ipython notebook:
```python
from sympy import *
init_session()
```
IPython console for SymPy 1.0 (Python 3.6.0-64-bit) (ground types:
python)
These commands were executed:
>>> from __future__ import division
>>> from sympy import *
>>> x, y, z, t = symbols('x y z t')
>>> k, m, n = symbols('k m n', integer=True)
>>> f, g, h = symbols('f g h', cls=Function)
>>> init_printing()
Documentation can be found at http://docs.sympy.org/1.0/
```python
f = Piecewise((0,x<0), (1,x<1), (0,True))
print(f.subs(x,-0.5), f.subs(x,0.5), f.subs(x,1.5))
plot(f,(x,-1,2))
```
0 1 0
---------------------------------------------------------------------------
TypeError Traceback (most recent call
last)
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/experimental_lambdify.py
in __call__(self, args)
193 #The result can be sympy.Float. Hence wrap it with
complex type.
--> 194 result = complex(self.lambda_func(args))
195 if abs(result.imag) > 1e-7 * abs(result):
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/experimental_lambdify.py
in __call__(self, *args, **kwargs)
310 def __call__(self, *args, **kwargs):
--> 311 return self.lambda_func(*args, **kwargs)
312
<string> in <lambda>(x0)
TypeError: '<' not supported between instances of 'complex' and 'int'
During handling of the above exception, another exception occurred:
TypeError Traceback (most recent call
last)
<ipython-input-2-447f720245d0> in <module>()
1 f = Piecewise((0,x<0), (1,x<1), (0,True))
2 print(f.subs(x,-0.5), f.subs(x,0.5), f.subs(x,1.5))
----> 3 plot(f,(x,-1,2))
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/plot.py
in plot(*args, **kwargs)
1282 plots = Plot(*series, **kwargs)
1283 if show:
-> 1284 plots.show()
1285 return plots
1286
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/plot.py
in show(self)
183 self._backend.close()
184 self._backend = self.backend(self)
--> 185 self._backend.show()
186
187 def save(self, path):
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/plot.py
in show(self)
1016
1017 def show(self):
-> 1018 self.process_series()
1019 #TODO after fixing
https://github.com/ipython/ipython/issues/1255
1020 # you can uncomment the next line and remove the
pyplot.show() call
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/plot.py
in process_series(self)
895 # Create the collections
896 if s.is_2Dline:
--> 897 collection =
self.LineCollection(s.get_segments())
898 self.ax.add_collection(collection)
899 elif s.is_contour:
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/plot.py
in get_segments(self)
501 list_segments.append([p, q])
502
--> 503 f_start = f(self.start)
504 f_end = f(self.end)
505 sample([self.start, f_start], [self.end, f_end], 0)
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/experimental_lambdify.py
in __call__(self, args)
227
use_evalf=True,
228
complex_wrap_evalf=True)
--> 229 result = self.lambda_func(args)
230 warnings.warn('The evaluation of the expression
is'
231 ' problematic. We are trying a failback
method'
/Users/boncelet/anaconda/lib/python3.6/site-packages/sympy/plotting/experimental_lambdify.py
in __call__(self, *args, **kwargs)
309
310 def __call__(self, *args, **kwargs):
--> 311 return self.lambda_func(*args, **kwargs)
312
313
<string> in <lambda>(x0)
TypeError: '<' not supported between instances of 'complex' and 'int'
```python
```
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