Improve simple correlated field interface

demos/getting_started_3.py

@@ -60,24 +60,19 @@ def main():
 
     args = {
         'offset_mean': 0,
-        'offset_std_mean': 1e-3,
-        'offset_std_std': 1e-6,
+        'offset_std': (1e-3, 1e-6),
 
         # Amplitude of field fluctuations
-        'fluctuations_mean':   2.0,  # 1.0
-        'fluctuations_stddev': 1.0,  # 1e-2
+        'fluctuations': (2., 1.), # 1.0, 1e-2
 
         # Exponent of power law power spectrum component
-        'loglogavgslope_mean': -2.0,  # -3.0
-        'loglogavgslope_stddev': 0.5,  # 0.5
+        'loglogavgslope': (-2., 0.5),  # -3.0, 0.5
 
         # Amplitude of integrated Wiener process power spectrum component
-        'flexibility_mean':   2.5,  # 1.0
-        'flexibility_stddev': 1.0,  # 0.5
+        'flexibility': (2.5, 1.),  # 1.0, 0.5
 
         # How ragged the integrated Wiener process component is
-        'asperity_mean':   0.5,  # 0.1
-        'asperity_stddev': 0.5  # 0.5
+        'asperity': (0.5, 0.5)  # 0.1, 0.5
     }
 
     correlated_field = ift.SimpleCorrelatedField(position_space, **args)

src/library/correlated_fields_simple.py

@@ -40,26 +40,27 @@ class SimpleCorrelatedField(Operator):
     spectrum, i.e. only one call of
     :func:`~nifty7.library.correlated_fields.CorrelatedFieldMaker.add_fluctuations`.
     """
-    def __init__(self, target, offset_mean, offset_std_mean, offset_std_std,
-                 fluctuations_mean, fluctuations_stddev, flexibility_mean,
-                 flexibility_stddev, asperity_mean, asperity_stddev,
-                 loglogavgslope_mean, loglogavgslope_stddev, prefix='',
+    def __init__(self, target, offset_mean, offset_std, fluctuations,
+                 flexibility, asperity, loglogavgslope, prefix='',
                  harmonic_partner=None):
         if harmonic_partner is None:
             harmonic_partner = target.get_default_codomain()
         else:
             target.check_codomain(harmonic_partner)
             harmonic_partner.check_codomain(target)
-        fluct = LognormalTransform(fluctuations_mean, fluctuations_stddev,
-                                   prefix + 'fluctuations', 0)
-        flex = LognormalTransform(flexibility_mean, flexibility_stddev,
-                                  prefix + 'flexibility', 0)
-        asp = LognormalTransform(asperity_mean, asperity_stddev,
-                                 prefix + 'asperity', 0)
-        avgsl = NormalTransform(loglogavgslope_mean, loglogavgslope_stddev,
-                                prefix + 'loglogavgslope', 0)
-        zm = LognormalTransform(offset_std_mean, offset_std_std,
-                                prefix + 'zeromode', 0)
+        for kk in [offset_std, fluctuations, loglogavgslope]:
+            if len(kk) != 2:
+                raise TypeError
+        for kk in [flexibility, asperity]:
+            if kk is None or len(kk) != 2:
+                raise TypeError
+        if flexibility is None and asperity is not None:
+            raise ValueError
+        fluct = LognormalTransform(*fluctuations, prefix + 'fluctuations', 0)
+        flex = LognormalTransform(*flexibility, prefix + 'flexibility', 0)
+        asp = LognormalTransform(*asperity, prefix + 'asperity', 0)
+        avgsl = NormalTransform(*loglogavgslope, prefix + 'loglogavgslope', 0)
+        zm = LognormalTransform(*offset_std, prefix + 'zeromode', 0)
 
         pspace = PowerSpace(harmonic_partner)
         twolog = _TwoLogIntegrations(pspace)

test/test_operators/test_correlated_fields.py

@@ -139,20 +139,15 @@ def test_complicated_vs_simple(seed, domain):
         loglogavgslope_stddev = _posrand()
         prefix = 'foobar'
         hspace = domain.get_default_codomain()
-        scf = ift.SimpleCorrelatedField(domain,
-                                        offset_mean,
-                                        offset_std_mean,
-                                        offset_std_std,
-                                        fluctuations_mean,
-                                        fluctuations_stddev,
-                                        flexibility_mean,
-                                        flexibility_stddev,
-                                        asperity_mean,
-                                        asperity_stddev,
-                                        loglogavgslope_mean,
-                                        loglogavgslope_stddev,
-                                        prefix=prefix,
-                                        harmonic_partner=hspace)
+        scf = ift.SimpleCorrelatedField(
+            domain,
+            offset_mean, (offset_std_mean, offset_std_std),
+            (fluctuations_mean, fluctuations_stddev),
+            (flexibility_mean, flexibility_stddev),
+            (asperity_mean, asperity_stddev),
+            (loglogavgslope_mean, loglogavgslope_stddev),
+            prefix=prefix,
+            harmonic_partner=hspace)
         cfm = ift.CorrelatedFieldMaker.make(offset_mean, offset_std_mean,
                                             offset_std_std, prefix)
         cfm.add_fluctuations(domain,