TypeError: ufunc 'add' did not contain a loop

Question

I use Anaconda and gdsCAD and get an error when all packages are installed correctly. Like explained here: http://pythonhosted.org/gdsCAD/

TypeError: ufunc 'add' did not contain a loop with signature matching types dtype('S32') dtype('S32') dtype('S32')

My imports look like this (In the end I imported everything):

import numpy as np
from gdsCAD import *
import matplotlib.pyplot as plt

My example code looks like this:

something = core.Elements()
box=shapes.Box( (5,5),(1,5),0.5)
core.default_layer = 1
core.default_colors = 2
something.add(box)
something.show()

My error message looks like this:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-5-2f90b960c1c1> in <module>()
 31 puffer_wafer = shapes.Circle((0.,0.), puffer_wafer_radius, puffer_line_thickness)
 32 bp.add(puffer_wafer)
---> 33 bp.show()
 34 wafer = shapes.Circle((0.,0.), wafer_radius, wafer_line_thickness)
 35 bp.add(wafer)

C:\Users\rpilz\AppData\Local\Continuum\Anaconda2\lib\site-packages\gdscad-0.4.5-py2.7.egg\gdsCAD\core.pyc in _show(self)
 80     ax.margins(0.1)
 81 
---> 82     artists=self.artist()
 83     for a in artists:
 84         a.set_transform(a.get_transform() + ax.transData)

C:\Users\rpilz\AppData\Local\Continuum\Anaconda2\lib\site-packages\gdscad-0.4.5-py2.7.egg\gdsCAD\core.pyc in artist(self, color)
952         art=[]
953         for p in self:
--> 954             art+=p.artist()
955         return art
956 

C:\Users\rpilz\AppData\Local\Continuum\Anaconda2\lib\site-packages\gdscad-0.4.5-py2.7.egg\gdsCAD\core.pyc in artist(self, color)
475         poly = lines.buffer(self.width/2.)
476 
--> 477         return [descartes.PolygonPatch(poly, lw=0, **self._layer_properties(self.layer))]
478 
479 

C:\Users\rpilz\AppData\Local\Continuum\Anaconda2\lib\site-packages\gdscad-0.4.5-py2.7.egg\gdsCAD\core.pyc in _layer_properties(layer)
103         # Default colors from previous versions
104         colors = ['k', 'r', 'g', 'b', 'c', 'm', 'y']
--> 105         colors += matplotlib.cm.gist_ncar(np.linspace(0.98, 0, 15))
106         color = colors[layer % len(colors)]
107         return {'color': color}

TypeError: ufunc 'add' did not contain a loop with signature matching types dtype('S32') dtype('S32') dtype('S32')    

Answer 1

The gdsCAD has been a pain from shapely install to this plotting issue.
This issue is because of wrong datatype being passed to colors function. It can be solved by editing the following line in core.py

colors += matplotlib.cm.gist_ncar(np.linspace(0.98, 0, 15))

to

colors += list(matplotlib.cm.gist_ncar(np.linspace(0.98, 0, 15)))

If you dont know where the core.py is located. Just type in:

from gdsCAD import *
core

This will give you the path of core.py file. Good luck !