Additional tests for packinfo generation & fast approximation for div and sqrt

pystencils_walberla_tests/test_packinfo_generation.py

+import pystencils as ps
+from pystencils_walberla import generate_pack_info_for_field, generate_pack_info_from_kernel
+from pystencils_walberla.cmake_integration import ManualCodeGenerationContext
+
+def test_packinfo_walberla_gen():
+    for openmp in (False, True):
+            for da in (False, True):
+                with ManualCodeGenerationContext(openmp=openmp, double_accuracy=da) as ctx:
+                    dtype = "float64" if ctx.double_accuracy else "float32"
+                    f, g = ps.fields("f, g(4): {}[3D]".format(dtype))
+                    generate_pack_info_for_field(ctx, 'PI1', f)
+
+                    src, dst = ps.fields("src, src_tmp: {}[2D]".format(dtype))
+                    stencil = [[0, -1, 0],
+                               [-1, 4, -1],
+                               [0, -1, 0]]
+                    assignments = [ps.assignment_from_stencil(stencil, src, dst, normalization_factor=4)]
+                    generate_pack_info_from_kernel(ctx, 'PI2', assignments)
+
+                    expected_files = ('PI1.cpp', 'PI1.h', 'PI2.cpp', 'PI2.h')
+                    assert all(e in ctx.files for e in expected_files)
+
+                    for file_name_to_test in ('PI1.cpp', 'PI2.cpp'):
+                        file_to_test = ctx.files[file_name_to_test]
+                        if openmp:
+                            assert '#pragma omp parallel' in file_to_test
+
+                        if da:
+                            assert 'float ' not in file_to_test
+                        else:
+                            assert 'double ' not in file_to_test
+