def test_symbol_renaming():
"""When two loops have assignments to the same symbol with different rhs and both
are pulled before the loops, one of them has to be renamed
"""
f, g = ps.fields("f, g : double[2D]")
a, b, c = [TypedSymbol(n, np.float64) for n in ('a', 'b', 'c')]
loop1 = LoopOverCoordinate(
Block(
[SympyAssignment(c, a + b),
SympyAssignment(g[0, 0], f[0, 0] + c)]), 0, 0, 10)
loop2 = LoopOverCoordinate(
Block([
SympyAssignment(c, a**2 + b**2),
SympyAssignment(g[0, 0], f[0, 0] + c)
]), 0, 0, 10)
block = Block([loop1, loop2])
move_constants_before_loop(block)
loops = block.atoms(LoopOverCoordinate)
assert len(loops) == 2
for loop in loops:
assert len(loop.body.args) == 1
assert len(loop.parent.args) == 4 # 2 loops + 2 subexpressions
assert loop.parent.args[0].lhs.name != loop.parent.args[1].lhs.name
def add(condition, dimensions, as_else_block=False):
nonlocal last_conditional
if staggered_field.index_dimensions == 1:
assignments = [
Assignment(staggered_field(d), expressions[d])
for d in dimensions
]
a_coll = AssignmentCollection(assignments, list(subexpressions))
a_coll = a_coll.new_filtered(
[staggered_field(d) for d in dimensions])
elif staggered_field.index_dimensions == 2:
assert staggered_field.has_fixed_index_shape
assignments = [
Assignment(staggered_field(d, i), expr) for d in dimensions
for i, expr in enumerate(expressions[d])
]
a_coll = AssignmentCollection(assignments, list(subexpressions))
a_coll = a_coll.new_filtered([
staggered_field(d, i)
for i in range(staggered_field.index_shape[1])
for d in dimensions
])
sp_assignments = [
SympyAssignment(a.lhs, a.rhs) for a in a_coll.all_assignments
]
if as_else_block and last_conditional:
new_cond = Conditional(condition, Block(sp_assignments))
last_conditional.false_block = Block([new_cond])
last_conditional = new_cond
else:
last_conditional = Conditional(condition, Block(sp_assignments))
final_assignments.append(last_conditional)
def test_jacobi_variable_field_size():
size = (3, 3, 3)
f = Field.create_generic("f", 3)
d = Field.create_generic("d", 3)
jacobi = SympyAssignment(
d[0, 0, 0], (f[1, 0, 0] + f[-1, 0, 0] + f[0, 1, 0] + f[0, -1, 0]) / 4)
body = Block([jacobi])
loop_node, gl_info = make_loop_over_domain(body)
ast_node = KernelFunction(loop_node,
'cpu',
'c',
make_python_function,
ghost_layers=gl_info)
resolve_field_accesses(ast_node)
move_constants_before_loop(ast_node)
src_field_c = np.random.rand(*size)
src_field_py = np.copy(src_field_c)
dst_field_c = np.zeros(size)
dst_field_py = np.zeros(size)
for x in range(1, size[0] - 1):
for y in range(1, size[1] - 1):
for z in range(1, size[2] - 1):
dst_field_py[x, y, z] = 0.25 * (
src_field_py[x - 1, y, z] + src_field_py[x + 1, y, z] +
src_field_py[x, y - 1, z] + src_field_py[x, y + 1, z])
kernel = ast_node.compile()
kernel(f=src_field_c, d=dst_field_c)
error = np.sum(np.abs(dst_field_py - dst_field_c))
np.testing.assert_allclose(error, 0.0, atol=1e-13)
def get_coordinate_symbol_assignment(name):
for ind_f in index_fields:
assert isinstance(ind_f.dtype, StructType), "Index fields have to have a struct data type"
data_type = ind_f.dtype
if data_type.has_element(name):
rhs = ind_f[0](name)
lhs = TypedSymbol(name, np.int64)
return SympyAssignment(lhs, rhs)
raise ValueError(f"Index {name} not found in any of the passed index fields")
def get_coordinate_symbol_assignment(name):
for idx_field in index_fields:
assert isinstance(
idx_field.dtype,
StructType), "Index fields have to have a struct data type"
data_type = idx_field.dtype
if data_type.has_element(name):
rhs = idx_field[0](name)
lhs = TypedSymbol(name,
BasicType(data_type.get_element_type(name)))
return SympyAssignment(lhs, rhs)
raise ValueError(
"Index %s not found in any of the passed index fields" % (name, ))
def test_staggered_iteration_manual():
dim = 2
f_arr = np.arange(5**dim).reshape([5] * dim)
s_arr = np.ones([5] * dim + [dim]) * 1234
s_arr_ref = s_arr.copy()
f = Field.create_from_numpy_array('f', f_arr)
s = Field.create_from_numpy_array('s', s_arr, index_dimensions=1)
eqs = []
counters = [
LoopOverCoordinate.get_loop_counter_symbol(i) for i in range(dim)
]
conditions = [counters[i] < f.shape[i] - 1 for i in range(dim)]
for d in range(dim):
eq = SympyAssignment(
s(d),
sum(f[o] for o in offsets_in_plane(d, 0, dim)) -
sum(f[o] for o in offsets_in_plane(d, -1, dim)))
cond = sp.And(*[conditions[i] for i in range(dim) if d != i])
eqs.append(Conditional(cond, eq))
kernel_ast = create_kernel(eqs, ghost_layers=[(1, 0), (1, 0), (1, 0)])
func = make_python_function(kernel_ast)
func(f=f_arr, s=s_arr_ref)
inner_loop = [
n for n in kernel_ast.atoms(ast.LoopOverCoordinate)
if n.is_innermost_loop
][0]
cut_loop(inner_loop, [4])
outer_loop = [
n for n in kernel_ast.atoms(ast.LoopOverCoordinate)
if n.is_outermost_loop
][0]
cut_loop(outer_loop, [4])
simplify_conditionals(kernel_ast.body, loop_counter_simplification=True)
cleanup_blocks(kernel_ast.body)
move_constants_before_loop(kernel_ast.body)
cleanup_blocks(kernel_ast.body)
assert not kernel_ast.atoms(
Conditional), "Loop cutting optimization did not work"
func_optimized = make_python_function(kernel_ast)
func_optimized(f=f_arr, s=s_arr)
np.testing.assert_almost_equal(s_arr_ref, s_arr)
def test_staggered_iteration():
dim = 2
f_arr = np.arange(5**dim).reshape([5] * dim).astype(np.float64)
s_arr = np.ones([5] * dim + [dim]) * 1234
s_arr_ref = s_arr.copy()
fields_fixed = (Field.create_from_numpy_array('f', f_arr),
Field.create_from_numpy_array('s',
s_arr,
index_dimensions=1))
fields_var = (Field.create_generic('f', 2),
Field.create_generic('s', 2, index_dimensions=1))
for f, s in [fields_var, fields_fixed]:
# --- Manual
eqs = []
counters = [
LoopOverCoordinate.get_loop_counter_symbol(i) for i in range(dim)
]
conditions = [counters[i] < f.shape[i] - 1 for i in range(dim)]
for d in range(dim):
eq = SympyAssignment(
s(d),
sum(f[o] for o in offsets_in_plane(d, 0, dim)) -
sum(f[o] for o in offsets_in_plane(d, -1, dim)))
cond = sp.And(*[conditions[i] for i in range(dim) if d != i])
eqs.append(Conditional(cond, eq))
func = create_kernel(eqs, ghost_layers=[(1, 0), (1, 0),
(1, 0)]).compile()
# --- Built-in optimized
expressions = []
for d in range(dim):
expressions.append(
sum(f[o] for o in offsets_in_plane(d, 0, dim)) -
sum(f[o] for o in offsets_in_plane(d, -1, dim)))
func_optimized = create_staggered_kernel(s, expressions).compile()
assert not func_optimized.ast.atoms(
Conditional), "Loop cutting optimization did not work"
func(f=f_arr, s=s_arr_ref)
func_optimized(f=f_arr, s=s_arr)
np.testing.assert_almost_equal(s_arr_ref, s_arr)
def boundary_conditional(boundary,
direction,
streaming_pattern,
prev_timestep,
lb_method,
output_field,
cse=False):
stencil = lb_method.stencil
dir_indices = direction_indices_in_direction(direction, stencil)
indexing = BetweenTimestepsIndexing(output_field, lb_method.stencil,
prev_timestep, streaming_pattern)
f_out, f_in = indexing.proxy_fields
inv_dir = indexing.inverse_dir_symbol
assignments = []
for direction_idx in dir_indices:
rule = boundary(f_out,
f_in,
direction_idx,
inv_dir,
lb_method,
index_field=None)
# rhs: replace f_out by post collision symbols.
rhs_substitutions = {
f_out(i): sym
for i, sym in enumerate(lb_method.post_collision_pdf_symbols)
}
rule = AssignmentCollection(
[rule]).new_with_substitutions(rhs_substitutions)
rule = indexing.substitute_proxies(rule)
ac = rule.new_without_subexpressions()
assignments += ac.main_assignments
border_cond = border_conditions(direction, output_field, ghost_layers=1)
if cse:
assignments = sympy_cse_on_assignment_list(assignments)
assignments = [SympyAssignment(a.lhs, a.rhs) for a in assignments]
return Conditional(border_cond, Block(assignments))
def equations_to_code(equations,
variable_prefix="lm.",
variables_without_prefix=[],
dtype="double"):
if isinstance(equations, AssignmentCollection):
equations = equations.all_assignments
variables_without_prefix = list(variables_without_prefix)
c_backend = CBackend()
result = []
left_hand_side_names = [e.lhs.name for e in equations]
for eq in equations:
assignment = SympyAssignment(
type_expr(eq.lhs, dtype=dtype),
type_expr(field_and_symbol_substitute(
eq.rhs, variable_prefix,
variables_without_prefix + left_hand_side_names),
dtype=dtype))
result.append(c_backend(assignment))
return "\n".join(result)
def test_jacobi_fixed_field_size():
size = (30, 20)
src_field_c = np.random.rand(*size)
src_field_py = np.copy(src_field_c)
dst_field_c = np.zeros(size)
dst_field_py = np.zeros(size)
f = Field.create_from_numpy_array("f", src_field_c)
d = Field.create_from_numpy_array("d", dst_field_c)
jacobi = SympyAssignment(d[0, 0],
(f[1, 0] + f[-1, 0] + f[0, 1] + f[0, -1]) / 4)
body = Block([jacobi])
loop_node, gl_info = make_loop_over_domain(body)
ast_node = KernelFunction(loop_node,
'cpu',
'c',
make_python_function,
ghost_layers=gl_info)
resolve_field_accesses(ast_node)
move_constants_before_loop(ast_node)
for x in range(1, size[0] - 1):
for y in range(1, size[1] - 1):
dst_field_py[
x,
y] = 0.25 * (src_field_py[x - 1, y] + src_field_py[x + 1, y] +
src_field_py[x, y - 1] + src_field_py[x, y + 1])
kernel = ast_node.compile()
kernel(f=src_field_c, d=dst_field_c)
error = np.sum(np.abs(dst_field_py - dst_field_c))
np.testing.assert_allclose(error, 0.0, atol=1e-13)
code_display = show_code(ast_node)
assert 'for' in str(code_display)
assert 'for' in code_display._repr_html_()
def test_sympy_assignment(default_assignment_simplifications):
assignment = SympyAssignment(dst[0, 0](0),
sp.log(x + 3) / sp.log(2) + sp.log(x**2 + 1))
config = ps.CreateKernelConfig(
default_assignment_simplifications=default_assignment_simplifications)
ast = ps.create_kernel([assignment], config=config)
code = ps.get_code_str(ast)
if default_assignment_simplifications:
assert 'log1p' in code
# constant term is directly evaluated
assert 'log2' not in code
else:
# no optimisations will be applied so the optimised version of log will not be in the code
assert 'log1p' not in code
assert 'log2' not in code
assignment.replace(assignment.lhs, dst[0, 0](1))
assignment.replace(assignment.rhs, sp.log(2))
assert assignment.lhs == dst[0, 0](1)
assert assignment.rhs == sp.log(2)
def create_staggered_kernel(assignments,
target: Target = Target.CPU,
gpu_exclusive_conditions=False,
**kwargs):
"""Kernel that updates a staggered field.
.. image:: /img/staggered_grid.svg
For a staggered field, the first index coordinate defines the location of the staggered value.
Further index coordinates can be used to store vectors/tensors at each point.
Args:
assignments: a sequence of assignments or an AssignmentCollection.
Assignments to staggered field are processed specially, while subexpressions and assignments to
regular fields are passed through to `create_kernel`. Multiple different staggered fields can be
used, but they all need to use the same stencil (i.e. the same number of staggered points) and
shape.
target: 'CPU' or 'GPU'
gpu_exclusive_conditions: disable the use of multiple conditionals inside the loop. The outer layers are then
handled in an else branch.
kwargs: passed directly to create_kernel, iteration_slice and ghost_layers parameters are not allowed
Returns:
AST, see `create_kernel`
"""
if 'ghost_layers' in kwargs:
assert kwargs['ghost_layers'] is None
del kwargs['ghost_layers']
if 'iteration_slice' in kwargs:
assert kwargs['iteration_slice'] is None
del kwargs['iteration_slice']
if 'omp_single_loop' in kwargs:
assert kwargs['omp_single_loop'] is False
del kwargs['omp_single_loop']
if isinstance(assignments, AssignmentCollection):
subexpressions = assignments.subexpressions + [
a for a in assignments.main_assignments
if not hasattr(a, 'lhs') or type(a.lhs) is not Field.Access
or not FieldType.is_staggered(a.lhs.field)
]
assignments = [
a for a in assignments.main_assignments
if hasattr(a, 'lhs') and type(a.lhs) is Field.Access
and FieldType.is_staggered(a.lhs.field)
]
else:
subexpressions = [
a for a in assignments
if not hasattr(a, 'lhs') or type(a.lhs) is not Field.Access
or not FieldType.is_staggered(a.lhs.field)
]
assignments = [
a for a in assignments
if hasattr(a, 'lhs') and type(a.lhs) is Field.Access
and FieldType.is_staggered(a.lhs.field)
]
if len(set([tuple(a.lhs.field.staggered_stencil)
for a in assignments])) != 1:
raise ValueError(
"All assignments need to be made to staggered fields with the same stencil"
)
if len(set([a.lhs.field.shape for a in assignments])) != 1:
raise ValueError(
"All assignments need to be made to staggered fields with the same shape"
)
staggered_field = assignments[0].lhs.field
stencil = staggered_field.staggered_stencil
dim = staggered_field.spatial_dimensions
shape = staggered_field.shape
counters = [
LoopOverCoordinate.get_loop_counter_symbol(i) for i in range(dim)
]
final_assignments = []
# find out whether any of the ghost layers is not needed
common_exclusions = set(["E", "W", "N", "S", "T", "B"][:2 * dim])
for direction in stencil:
exclusions = set(["E", "W", "N", "S", "T", "B"][:2 * dim])
for elementary_direction in direction:
exclusions.remove(inverse_direction_string(elementary_direction))
common_exclusions.intersection_update(exclusions)
ghost_layers = [[0, 0] for d in range(dim)]
for direction in common_exclusions:
direction = direction_string_to_offset(direction)
for d, s in enumerate(direction):
if s == 1:
ghost_layers[d][1] = 1
elif s == -1:
ghost_layers[d][0] = 1
def condition(direction):
"""exclude those staggered points that correspond to fluxes between ghost cells"""
exclusions = set(["E", "W", "N", "S", "T", "B"][:2 * dim])
for elementary_direction in direction:
exclusions.remove(inverse_direction_string(elementary_direction))
conditions = []
for e in exclusions:
if e in common_exclusions:
continue
offset = direction_string_to_offset(e)
for i, o in enumerate(offset):
if o == 1:
conditions.append(counters[i] < shape[i] - 1)
elif o == -1:
conditions.append(counters[i] > 0)
return sp.And(*conditions)
if gpu_exclusive_conditions:
outer_assignment = None
conditions = {direction: condition(direction) for direction in stencil}
for num_conditions in range(len(stencil)):
for combination in itertools.combinations(conditions.values(),
num_conditions):
for assignment in assignments:
direction = stencil[assignment.lhs.index[0]]
if conditions[direction] in combination:
assignment = SympyAssignment(assignment.lhs,
assignment.rhs)
outer_assignment = Conditional(sp.And(*combination),
Block([assignment]),
outer_assignment)
inner_assignment = []
for assignment in assignments:
inner_assignment.append(
SympyAssignment(assignment.lhs, assignment.rhs))
last_conditional = Conditional(
sp.And(*[condition(d) for d in stencil]), Block(inner_assignment),
outer_assignment)
final_assignments = [s for s in subexpressions if not hasattr(s, 'lhs')] + \
[SympyAssignment(s.lhs, s.rhs) for s in subexpressions if hasattr(s, 'lhs')] + \
[last_conditional]
if target == Target.CPU:
from pystencils.cpu import create_kernel as create_kernel_cpu
ast = create_kernel_cpu(final_assignments,
ghost_layers=ghost_layers,
omp_single_loop=False,
**kwargs)
else:
ast = create_kernel(final_assignments,
ghost_layers=ghost_layers,
target=target,
**kwargs)
return ast
for assignment in assignments:
direction = stencil[assignment.lhs.index[0]]
sp_assignments = [s for s in subexpressions if not hasattr(s, 'lhs')] + \
[SympyAssignment(s.lhs, s.rhs) for s in subexpressions if hasattr(s, 'lhs')] + \
[SympyAssignment(assignment.lhs, assignment.rhs)]
last_conditional = Conditional(condition(direction),
Block(sp_assignments))
final_assignments.append(last_conditional)
remove_start_conditional = any([gl[0] == 0 for gl in ghost_layers])
prepend_optimizations = [
lambda ast: remove_conditionals_in_staggered_kernel(
ast, remove_start_conditional), move_constants_before_loop
]
if 'cpu_prepend_optimizations' in kwargs:
prepend_optimizations += kwargs['cpu_prepend_optimizations']
del kwargs['cpu_prepend_optimizations']
ast = create_kernel(final_assignments,
ghost_layers=ghost_layers,
target=target,
omp_single_loop=False,
cpu_prepend_optimizations=prepend_optimizations,
**kwargs)
return ast
def create_cuda_kernel(assignments,
function_name="kernel",
type_info=None,
indexing_creator=BlockIndexing,
iteration_slice=None,
ghost_layers=None,
skip_independence_check=False):
assert assignments, "Assignments must not be empty!"
fields_read, fields_written, assignments = add_types(assignments, type_info, not skip_independence_check)
all_fields = fields_read.union(fields_written)
read_only_fields = set([f.name for f in fields_read - fields_written])
buffers = set([f for f in all_fields if FieldType.is_buffer(f) or FieldType.is_custom(f)])
fields_without_buffers = all_fields - buffers
field_accesses = set()
num_buffer_accesses = 0
for eq in assignments:
field_accesses.update(eq.atoms(Field.Access))
field_accesses = {e for e in field_accesses if not e.is_absolute_access}
num_buffer_accesses += sum(1 for access in eq.atoms(Field.Access) if FieldType.is_buffer(access.field))
common_shape = get_common_shape(fields_without_buffers)
if iteration_slice is None:
# determine iteration slice from ghost layers
if ghost_layers is None:
# determine required number of ghost layers from field access
required_ghost_layers = max([fa.required_ghost_layers for fa in field_accesses])
ghost_layers = [(required_ghost_layers, required_ghost_layers)] * len(common_shape)
iteration_slice = []
if isinstance(ghost_layers, int):
for i in range(len(common_shape)):
iteration_slice.append(slice(ghost_layers, -ghost_layers if ghost_layers > 0 else None))
ghost_layers = [(ghost_layers, ghost_layers)] * len(common_shape)
else:
for i in range(len(common_shape)):
iteration_slice.append(slice(ghost_layers[i][0],
-ghost_layers[i][1] if ghost_layers[i][1] > 0 else None))
indexing = indexing_creator(field=list(fields_without_buffers)[0], iteration_slice=iteration_slice)
coord_mapping = indexing.coordinates
cell_idx_assignments = [SympyAssignment(LoopOverCoordinate.get_loop_counter_symbol(i), value)
for i, value in enumerate(coord_mapping)]
cell_idx_symbols = [LoopOverCoordinate.get_loop_counter_symbol(i) for i, _ in enumerate(coord_mapping)]
assignments = cell_idx_assignments + assignments
block = Block(assignments)
block = indexing.guard(block, common_shape)
unify_shape_symbols(block, common_shape=common_shape, fields=fields_without_buffers)
ast = KernelFunction(block,
Target.GPU,
Backend.CUDA,
make_python_function,
ghost_layers,
function_name,
assignments=assignments)
ast.global_variables.update(indexing.index_variables)
base_pointer_spec = [['spatialInner0']]
base_pointer_info = {f.name: parse_base_pointer_info(base_pointer_spec, [2, 1, 0],
f.spatial_dimensions, f.index_dimensions)
for f in all_fields}
coord_mapping = {f.name: cell_idx_symbols for f in all_fields}
loop_strides = list(fields_without_buffers)[0].shape
if any(FieldType.is_buffer(f) for f in all_fields):
resolve_buffer_accesses(ast, get_base_buffer_index(ast, indexing.coordinates, loop_strides), read_only_fields)
resolve_field_accesses(ast, read_only_fields, field_to_base_pointer_info=base_pointer_info,
field_to_fixed_coordinates=coord_mapping)
# add the function which determines #blocks and #threads as additional member to KernelFunction node
# this is used by the jit
# If loop counter symbols have been explicitly used in the update equations (e.g. for built in periodicity),
# they are defined here
undefined_loop_counters = {LoopOverCoordinate.is_loop_counter_symbol(s): s for s in ast.body.undefined_symbols
if LoopOverCoordinate.is_loop_counter_symbol(s) is not None}
for i, loop_counter in undefined_loop_counters.items():
ast.body.insert_front(SympyAssignment(loop_counter, indexing.coordinates[i]))
ast.indexing = indexing
return ast