Implemented Logarithm

pystencils/kernel_contrains_check.py

@@ -10,10 +10,11 @@ from pystencils.field import Field
 from pystencils.node_collection import NodeCollection
 from pystencils.transformations import NestedScopes
 
-
+# TODO use this in Constraint Checker
 accepted_functions = [
     sp.Pow,
     sp.sqrt,
+    sp.log,
     # TODO trigonometric functions (and whatever tests will fail)
 ]
 

pystencils/typing/leaf_typing.py

@@ -212,7 +212,7 @@ class TypeAdder:
                     new_args.append(a)
             return expr.func(*new_args) if new_args else expr, collated_type
         elif isinstance(expr, (sp.Pow, sp.exp, InverseTrigonometricFunction, TrigonometricFunction,
-                               HyperbolicFunction)):
+                               HyperbolicFunction, sp.log)):
             args_types = [self.figure_out_type(arg) for arg in expr.args]
             collated_type = collate_types([t for _, t in args_types])
             new_args = [a if t.dtype_eq(collated_type) else CastFunc(a, collated_type) for a, t in args_types]

pystencils_tests/test_logarithm.py

+import pytest
+import numpy as np
+import sympy as sp
+
+import pystencils as ps
+
+
+@pytest.mark.parametrize('dtype', ["float64", "float32"])
+def test_log(dtype):
+    a = sp.Symbol("a")
+    x = ps.fields(f'x: {dtype}[1d]')
+
+    assignments = ps.AssignmentCollection({x.center(): sp.log(a)})
+
+    ast = ps.create_kernel(assignments)
+    code = ps.get_code_str(ast)
+    kernel = ast.compile()
+
+    # ps.show_code(ast)
+
+    if dtype == "float64":
+        assert "float" not in code
+
+    array = np.zeros((10,), dtype=dtype)
+    kernel(x=array, a=100)
+    assert np.allclose(array, 4.60517019)