Merge pull request #310 from GeoStat-Framework/update_uniform_trans

Update uniform trans

src/gstools/transform/array.py

@@ -215,9 +215,9 @@ def array_to_lognormal(field):
     return np.exp(field)
 
 
-def array_to_uniform(field, mean=None, var=None):
+def array_to_uniform(field, mean=None, var=None, low=0.0, high=1.0):
     """
-    Transform normal distribution to uniform distribution on [0, 1].
+    Transform normal distribution to uniform distribution on [low, high].
 
     Parameters
     ----------
@@ -230,6 +230,12 @@ def array_to_uniform(field, mean=None, var=None):
         Variance of the given field.
         If None is given, the variance will be calculated.
         Default: :any:`None`
+    low : :class:`float`, optional
+        Lower bound for the uniform distribution.
+        Default: 0.0
+    high : :class:`float`, optional
+        Upper bound for the uniform distribution.
+        Default: 1.0
 
     Returns
     -------
@@ -239,7 +245,9 @@ def array_to_uniform(field, mean=None, var=None):
     field = np.asarray(field)
     mean = np.mean(field) if mean is None else float(mean)
     var = np.var(field) if var is None else float(var)
-    return 0.5 * (1 + erf((field - mean) / np.sqrt(2 * var)))
+    return (
+        0.5 * (1 + erf((field - mean) / np.sqrt(2 * var))) * (high - low) + low
+    )
 
 
 def array_to_arcsin(field, mean=None, var=None, a=None, b=None):

src/gstools/transform/field.py

@@ -548,6 +548,8 @@ def normal_to_lognormal(
 
 def normal_to_uniform(
     fld,
+    low=0.0,
+    high=1.0,
     field="field",
     store=True,
     process=False,
@@ -562,14 +564,31 @@ def normal_to_uniform(
     ----------
     fld : :any:`Field`
         Field class containing a generated field.
+    low : :class:`float`, optional
+        Lower bound for the uniform distribution.
+        Default: 0.0
+    high : :class:`float`, optional
+        Upper bound for the uniform distribution.
+        Default: 1.0
+    field : :class:`str`, optional
+        Name of field to be transformed. The default is "field".
+    store : :class:`str` or :class:`bool`, optional
+        Whether to store field inplace (True/False) or under a given name.
+        The default is True.
+    process : :class:`bool`, optional
+        Whether to process in/out fields with trend, normalizer and mean
+        of given Field instance. The default is False.
     keep_mean : :class:`bool`, optional
         Whether to keep the mean of the field if process=True.
         The default is True.
     """
     if not process:
         _check_for_default_normal(fld)
     kw = dict(
-        mean=0.0 if process and not keep_mean else fld.mean, var=fld.model.sill
+        mean=0.0 if process and not keep_mean else fld.mean,
+        var=fld.model.sill,
+        low=low,
+        high=high,
     )
     return apply_function(
         fld=fld,