problem with Python 3.6 + PyX

[stalker5]

Hello everybody !

I'm have a problem with this little program

#---début---
from pyx import *

g = graph.graphxy(width=8, x=graph.axis.linear(min=-15, max=15))
g.plot(graph.data.function("y(x)=sin(x)/x"))
g.writeEPSfile("function")
g.writePDFfile("function")
g.writeSVGfile("function")
#--- fin---

Python protest :

--begin error message

Running script: "/Users/draper/Documents/2016-2017/PYTHON/pyx test.py"
Traceback (most recent call last):
   File "/Users/draper/Documents/2016-2017/PYTHON/pyx test.py", line 5, 
in <module>
     g.writeEPSfile("function")
   File "/usr/local/lib/python3.6/site-packages/pyx/canvas.py", line 50, 
in wrappedindocument
     return method(d, file, **write_kwargs)
   File "/usr/local/lib/python3.6/site-packages/pyx/document.py", line 
185, in writeEPSfile
     pswriter.EPSwriter(self, f, **kwargs)
   File "/usr/local/lib/python3.6/site-packages/pyx/pswriter.py", line 
142, in __init__
     page.processPS(pagefile, self, acontext, registry, pagebbox)
   File "/usr/local/lib/python3.6/site-packages/pyx/document.py", line 
132, in processPS
     self._process("processPS", *args)
   File "/usr/local/lib/python3.6/site-packages/pyx/document.py", line 
78, in _process
     bbox.set(self.canvas.bbox()) # this bbox is not accurate
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/graph.py", 
line 181, in bbox
     self.finish()
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/graph.py", 
line 303, in finish
     self.doaxes()
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/graph.py", 
line 580, in doaxes
     self.dolayout()
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/graph.py", 
line 564, in dolayout
     self.doaxiscreate(axisname)
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/graph.py", 
line 240, in doaxiscreate
     self.axes[axisname].create()
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/axis/axis.py", 
line 591, in create
     self.canvas = self.axis.create(self.data, self.positioner, 
self.graphtexrunner, self.errorname)
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/axis/axis.py", 
line 250, in create
     return _regularaxis._create(self, data, positioner, graphtexrunner, 
self.parter, self.rater, errorname)
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/axis/axis.py", 
line 220, in _create
     variants[0].storedcanvas = layout(variants[0])
   File "/usr/local/lib/python3.6/site-packages/pyx/graph/axis/axis.py", 
line 141, in layout
     self.painter.paint(canvas, data, self, positioner)
   File 
"/usr/local/lib/python3.6/site-packages/pyx/graph/axis/painter.py", line 
192, in paint
     t.temp_labelbox = canvas.texrunner.text_pt(t.temp_x_pt, 
t.temp_y_pt, t.label, labelattrs)
   File "/usr/local/lib/python3.6/site-packages/pyx/text.py", line 1428, 
in wrapped
     return f(self, *args, **kwargs)
   File "/usr/local/lib/python3.6/site-packages/pyx/text.py", line 1459, 
in text_pt
     return self.instance.text_pt(*args, **kwargs)
   File "/usr/local/lib/python3.6/site-packages/pyx/text.py", line 1278, 
in text_pt
     left_pt, right_pt, height_pt, depth_pt = self.do_typeset(expr, 
self.texmessages_run_default + self.texmessages_run + texmessages)
   File "/usr/local/lib/python3.6/site-packages/pyx/text.py", line 1201, 
in do_typeset
     self.do_start()
   File "/usr/local/lib/python3.6/site-packages/pyx/text.py", line 1344, 
in do_start
     super().do_start()
   File "/usr/local/lib/python3.6/site-packages/pyx/text.py", line 1156, 
in do_start
     self.popen = config.Popen(cmd, stdin=config.PIPE, 
stdout=config.PIPE, stderr=config.STDOUT, bufsize=0)
   File "/usr/local/lib/python3.6/site-packages/pyx/config.py", line 
190, in Popen
     return subprocess.Popen(cmd, *args, **kwargs)
   File 
"/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", 
line 707, in __init__
     restore_signals, start_new_session)
   File 
"/usr/local/Cellar/python3/3.6.0/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", 
line 1326, in _execute_child
     raise child_exception_type(errno_num, err_msg)
FileNotFoundError: [Errno 2] No such file or directory: 'tex'

-- end eroor message --

I search some solution, but without success.
Anybody have a idea ??

Thx a lot. Have a nice day.

--
Olivier