correlated_field.py: Raise errors for users

Instead of validating the input via `assert`s in user-accessible
functions, raise appropriate errors.

nifty6/library/correlated_fields.py

@@ -51,8 +51,11 @@ def _lognormal_moments(mean, sig, N=0):
         mean, sig = np.asfarray(mean), np.asfarray(sig)
     else:
         mean, sig = (_reshaper(param, N) for param in (mean, sig))
-    assert np.all(mean > 0)
-    assert np.all(sig > 0)
+    if not np.all(mean > 0):
+        raise ValueError(f"mean must be greater 0; got {mean!r}")
+    if not np.all(sig > 0):
+        raise ValueError(f"sig must be greater 0; got {sig!r}")
+
     logsig = np.sqrt(np.log((sig/mean)**2 + 1))
     logmean = np.log(mean) - logsig**2/2
     return logmean, logsig
@@ -334,7 +337,8 @@ class _Amplitude(Operator):
 
 class CorrelatedFieldMaker:
     def __init__(self, amplitude_offset, prefix, total_N):
-        assert isinstance(amplitude_offset, Operator)
+        if not isinstance(amplitude_offset, Operator):
+            raise TypeError("amplitude_offset needs to be an operator")
         self._a = []
         self._position_spaces = []
 
@@ -348,8 +352,8 @@ class CorrelatedFieldMaker:
              dofdex=None):
         if dofdex is None:
             dofdex = np.full(total_N, 0)
-        else:
-            assert len(dofdex) == total_N
+        elif len(dofdex) != total_N:
+            raise ValueError("length of dofdex needs to match total_N")
         N = max(dofdex) + 1 if total_N > 0 else 0
         zm = _LognormalMomentMatching(offset_amplitude_mean,
                                       offset_amplitude_stddev,
@@ -381,8 +385,8 @@ class CorrelatedFieldMaker:
 
         if dofdex is None:
             dofdex = np.full(self._total_N, 0)
-        else:
-            assert len(dofdex) == self._total_N
+        elif len(dofdex) != self._total_N:
+            raise ValueError("length of dofdex needs to match total_N")
 
         if self._total_N > 0:
             space = 1
@@ -501,7 +505,9 @@ class CorrelatedFieldMaker:
 
     def moment_slice_to_average(self, fluctuations_slice_mean, nsamples=1000):
         fluctuations_slice_mean = float(fluctuations_slice_mean)
-        assert fluctuations_slice_mean > 0
+        if not fluctuations_slice_mean > 0:
+            msg = "fluctuations_slice_mean must be greater zero; got {!r}"
+            raise ValueError(msg.format(fluctuations_slice_mean))
         from ..sugar import from_random
         scm = 1.
         for a in self._a:
@@ -547,7 +553,8 @@ class CorrelatedFieldMaker:
         """Returns operator which acts on prior or posterior samples"""
         if len(self._a) == 0:
             raise NotImplementedError
-        assert space < len(self._a)
+        if space >= len(self._a):
+            raise ValueError(f"invalid space specified; got {space!r}")
         if len(self._a) == 1:
             return self.average_fluctuation(0)
         q = 1.
@@ -563,7 +570,8 @@ class CorrelatedFieldMaker:
         """Returns operator which acts on prior or posterior samples"""
         if len(self._a) == 0:
             raise NotImplementedError
-        assert space < len(self._a)
+        if space >= len(self._a):
+            raise ValueError(f"invalid space specified; got {space!r}")
         if len(self._a) == 1:
             return self._a[0].fluctuation_amplitude
         return self._a[space].fluctuation_amplitude
@@ -584,7 +592,8 @@ class CorrelatedFieldMaker:
         """Computes slice fluctuations from collection of field (defined in signal
         space) realizations."""
         ldom = len(samples[0].domain)
-        assert space < ldom
+        if space >= ldom:
+            raise ValueError(f"invalid space specified; got {space!r}")
         if ldom == 1:
             return _total_fluctuation_realized(samples)
         res1, res2 = 0., 0.
@@ -601,7 +610,8 @@ class CorrelatedFieldMaker:
         """Computes average fluctuations from collection of field (defined in signal
         space) realizations."""
         ldom = len(samples[0].domain)
-        assert space < ldom
+        if space >= ldom:
+            raise ValueError(f"invalid space specified; got {space!r}")
         if ldom == 1:
             return _total_fluctuation_realized(samples)
         spaces = ()