Validation errors

I noticed that there isn’t a single call of .validate() anywhere in the discretize package or testing suite. Perhaps this was overlooked?

I figured this out because I was adding validation checks for MR #114 and I can’t validate any meshes without the following difficult to trace back error (on the master branch):

import discretize
tens = discretize.TensorMesh([16, 16])
tens.validate()

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-2-fc8c65b21a77> in <module>()
      1 import discretize
      2 tens = discretize.TensorMesh([16, 16])
----> 3 tens.validate()

/Users/bane/anaconda3/envs/disc/lib/python2.7/site-packages/properties/base/base.pyc in validate(self)
    409                 )
    410             elif self._non_validation_error:
--> 411                 raise self._non_validation_error                               #pylint: disable=raising-bad-type
    412             return True
    413         finally:

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

[prisae]

I think it is a backwards compatibility issue, as at some point you could do this comparison, but they changed it at some point, if I remember right.

I haven’t looked into it in detail, and @rowanc1 or @lheagy are probably better suited to answer that. But at least as a short fix you can probably simply change line 55 from

if change['previous'] != properties.undefined:

to

if np.any(change['previous'] != properties.undefined):

See this dummy example:

In [1]: a = np.arange(10)                                                       

In [2]: b = 4                                                                   

In [3]: if a == b: 
   ...:     print('yes')                                                        
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-4-450e19031455> in <module>
----> 1 if a == b:
      2     print('yes')

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

In [4]: if np.any(a == b): 
   ...:     print('yes')                                                        
yes

[banesullivan]

Here’s another one with the TreeMesh (after fixing line 55 in Base.py as mentioned above)

import discretize
from discretize import utils

tree = discretize.TreeMesh([16, 16])

def refine(cell):
    if np.sqrt(((np.r_[cell.center]-0.5)**2).sum()) < 0.4:
        return 4
    return 3

tree.refine(refine)

tree.validate()

With the following traceback:

---------------------------------------------------------------------------
ValidationError                           Traceback (most recent call last)
<ipython-input-3-4403a86a60ca> in <module>()
     27 
     28 # plt.show()
---> 29 tree.validate()

~/anaconda3/envs/ogv/lib/python3.6/site-packages/properties/base/base.py in validate(self)
    406                 raise utils.ValidationError(
    407                     message='\n- '.join(msgs),
--> 408                     _error_tuples=self._validation_error_tuples,
    409                 )
    410             elif self._non_validation_error:

ValidationError: Validation failed:
- The 'x0' property of a TreeMesh instance is required and has not been set.