Add error for NaN encoders

nengo · Oct 30, 2019 · bb8010a · bb8010a
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diff --git a/CHANGES.rst b/CHANGES.rst
@@ -29,6 +29,8 @@ Release history
   (`#226 <https://github.com/nengo/nengo-loihi/pull/226>`__)
 - Connections now support ``Sparse`` transforms.
   (`#240 <https://github.com/nengo/nengo-loihi/pull/240>`__)
+- A more informative error message is raised if any encoders contain NaNs.
+  (`#251 <https://github.com/nengo/nengo-loihi/pull/251>`__)
 
 **Changed**
 

diff --git a/nengo_loihi/builder/ensemble.py b/nengo_loihi/builder/ensemble.py
@@ -83,6 +83,13 @@ def build_ensemble(model, ens):
     if ens.normalize_encoders:
         encoders /= npext.norm(encoders, axis=1, keepdims=True)
 
+    if np.any(np.isnan(encoders)):
+        raise BuildError(
+            "NaNs detected in %r encoders. This usually means that you had zero-length "
+            "encoders that were normalized, resulting in NaNs. Ensure all encoders "
+            "have non-zero length, or set `normalize_encoders=False`." % ens
+        )
+
     # Build the neurons
     gain, bias, max_rates, intercepts = get_gain_bias(ens, rng, model.intercept_limit)