Treat scaling correctly

src/library/special_distributions.py

@@ -23,6 +23,7 @@ from .. import random
 from ..domain_tuple import DomainTuple
 from ..domains.unstructured_domain import UnstructuredDomain
 from ..field import Field
+from ..operators.adder import Adder
 from ..operators.operator import Operator
 from ..sugar import makeOp
 
@@ -133,9 +134,8 @@ def LogInverseGammaOperator(domain, alpha, q, delta=1e-2):
     """
     op = _InterpolationOperator(domain, lambda x: np.log(invgamma.ppf(norm._cdf(x), float(alpha))),
                                 -8.2, 8.2, delta)
-    if np.isscalar(q):
-        return op.scale(q)
-    return makeOp(q) @ op
+    q = np.log(q) if np.isscalar(q) else q.log()
+    return Adder(q, domain=op.target) @ op
 
 
 class UniformOperator(Operator):