Notebook

In [1]:

from pystencils.session import *

Test field equality behaviour¶

Fields create with same parameters are equal

In [2]:

f1 = ps.Field.create_generic('f', spatial_dimensions=2, index_dimensions=0)
f2 = ps.Field.create_generic('f', spatial_dimensions=2, index_dimensions=0)

assert f1 == f2

In [3]:

print("Field ids equal in accesses: ", id(f1.center._field) == id(f2.center._field))
print("Field accesses equal: ", f1.center == f2.center)

Field ids equal in accesses:  True
Field accesses equal:  True

In [4]:

f1 = ps.Field.create_generic('f', spatial_dimensions=1, index_dimensions=0)
f2 = ps.Field.create_generic('f', spatial_dimensions=2, index_dimensions=0)
assert f1 != f2

In [5]:

f1 = ps.Field.create_generic('f', spatial_dimensions=1, index_dimensions=0)
f2 = ps.Field.create_generic('f', spatial_dimensions=1, index_dimensions=0, dtype=np.float32)
assert f1 != f2

Properties of fields:

field_type: enum distinguishing normal from index or buffer fields
_dtype: data type of field elements
_layout: tuple indicating the memory linearization order
shape: size of field for each dimension
strides: number of elements to jump over to increase coordinate of this dimension by one
latex_name: optional display name when field is printed as latex

Equality compare of fields:

field has __eq__ and __hash__ overridden
all parameter but latex_name are considered for equality

Test field access equality behaviour¶

In [6]:

f1 = ps.Field.create_generic('f', spatial_dimensions=1, index_dimensions=0)
f2 = ps.Field.create_generic('f', spatial_dimensions=1, index_dimensions=0)
assert f1.center == f2.center

In [7]:

f1 = ps.Field.create_generic('f', spatial_dimensions=1, index_dimensions=0)
f2 = ps.Field.create_generic('f', spatial_dimensions=1, index_dimensions=0, dtype=np.float32)
assert f1.center != f2.center

In [8]:

def print_field_accesses_debug(expr):
    from pystencils import Field
    fas = list(expr.atoms(Field.Access))
    fields = list({e.field for e in fas})
    print("Field Accesses:")
    for fa in fas:
        print(f"   - {fa}, hash {hash(fa)}, offsets {fa._offsets}, index {fa._index}, {fa._hashable_content()}")
    print("")
    for i in range(len(fas)):
        for j in range(len(fas)):
            if not i < j: 
                continue
            print( f"   -> {i},{j}  {fas[i]} == {fas[j]}: {fas[i] == {fas[j]}}")
    
    print("Fields")
    for f in fields:
        print(f"  - {f}, {id(f)}, shape {f.shape}, strides {f.strides}, {f._dtype}, {f.field_type}, layout {f.layout}")
    print("")
    for i in range(len(fields)):
        for j in range(len(fields)):
            if not i < j: 
                continue
            print(f"  - {fields[i]} == {fields[j]}: {fields[i] == fields[j]}, ids equal {id(fields[i])==id(fields[j])}, hash equal {hash(fields[i])==hash(fields[j])}")

In [9]:

print_field_accesses_debug(f1.center * f2.center)

Field Accesses:
   - f[0], hash -8859424145258271267, offsets (0,), index (), ((('f_C', ('commutative', True), ('complex', True), ('extended_real', True), ('finite', True), ('hermitian', True), ('imaginary', False), ('infinite', False), ('real', True)), 2305067722319023373), ((0,), (_size_f_0,), (_stride_f_0,), <FieldType.GENERIC: 0>, 'f', None, double), 0)
   - f[0], hash -6454673863007224785, offsets (0,), index (), ((('f_C', ('commutative', True), ('complex', True), ('extended_real', True), ('finite', True), ('hermitian', True), ('imaginary', False), ('infinite', False), ('real', True)), 4093629613697528859), ((0,), (_size_f_0,), (_stride_f_0,), <FieldType.GENERIC: 0>, 'f', None, float), 0)

   -> 0,1  f[0] == f[0]: False
Fields
  - f, 4881406800, shape (_size_f_0,), strides (_stride_f_0,), double, FieldType.GENERIC, layout (0,)
  - f, 4881445024, shape (_size_f_0,), strides (_stride_f_0,), float, FieldType.GENERIC, layout (0,)

  - f == f: False, ids equal False, hash equal False