Fix: type of sqrt(int) was int not floating point type

pystencils/data_types.py

@@ -548,7 +548,13 @@ def get_type_of_expression(expr,
         if vec_args:
             result = VectorType(result, width=vec_args[0].width)
         return result
-    elif isinstance(expr, (sp.Pow, sp.Sum, sp.Product)):
+    elif isinstance(expr, sp.Pow):
+        base_type = get_type(expr.args[0])
+        if expr.exp.is_integer:
+            return base_type
+        else:
+            return collate_types([create_type(default_float_type), base_type])
+    elif isinstance(expr, (sp.Sum, sp.Product)):
         return get_type(expr.args[0])
     elif isinstance(expr, sp.Expr):
         expr: sp.Expr

pystencils_tests/test_types.py

 import sympy as sp
-
+import numpy as np
+import pystencils as ps
 from pystencils import data_types
-from pystencils.data_types import *
-from pystencils.kernelparameters import FieldShapeSymbol
+from pystencils.data_types import TypedSymbol, get_type_of_expression, VectorType, collate_types, create_type
 
 
 def test_parsing():
@@ -25,7 +25,6 @@ def test_collation():
 
 
 def test_dtype_of_constants():
-
     # Some come constants are neither of type Integer,Float,Rational and don't have args
     # >>> isinstance(pi, Integer)
     # False
@@ -39,13 +38,25 @@ def test_dtype_of_constants():
 
 
 def test_assumptions():
-
-    x = pystencils.fields('x:  float32[3d]')
+    x = ps.fields('x:  float32[3d]')
 
     assert x.shape[0].is_nonnegative
     assert (2 * x.shape[0]).is_nonnegative
     assert (2 * x.shape[0]).is_integer
-    assert(TypedSymbol('a', create_type('uint64'))).is_nonnegative
+    assert (TypedSymbol('a', create_type('uint64'))).is_nonnegative
     assert (TypedSymbol('a', create_type('uint64'))).is_positive is None
     assert (TypedSymbol('a', create_type('uint64')) + 1).is_positive
     assert (x.shape[0] + 1).is_real
+
+
+def test_sqrt_of_integer():
+    """Regression test for bug where sqrt(3) was classified as integer"""
+    f = ps.fields("f: [1D]")
+    tmp = sp.symbols("tmp")
+
+    assignments = [ps.Assignment(tmp, sp.sqrt(3)),
+                   ps.Assignment(f[0], tmp)]
+    arr = np.array([1], dtype=np.float64)
+    kernel = ps.create_kernel(assignments).compile()
+    kernel(f=arr)
+    assert 1.7 < arr[0] < 1.8