def iet_insert_decls(iet, external):
"""
Transform the input IET inserting the necessary symbol declarations.
Declarations are placed as close as possible to the first symbol occurrence.
Parameters
----------
iet : Node
The input Iteration/Expression tree.
external : tuple, optional
The symbols defined in some outer Callable, which therefore must not
be re-defined.
"""
iet = as_tuple(iet)
# Classify and then schedule declarations to stack/heap
allocator = Allocator()
for k, v in MapSections().visit(iet).items():
if k.is_Expression:
if k.is_scalar_assign:
# On the stack
site = v if v else iet
allocator.push_scalar_on_stack(site[-1], k)
continue
objs = [k.write]
elif k.is_Call:
objs = k.arguments
for i in objs:
try:
if i.is_LocalObject:
# On the stack
site = v if v else iet
allocator.push_object_on_stack(site[-1], i)
elif i.is_Array:
if i in as_tuple(external):
# The Array is defined in some other IET
continue
elif i._mem_stack:
# On the stack
key = lambda i: not i.is_Parallel
site = filter_iterations(v, key=key) or iet
allocator.push_object_on_stack(site[-1], i)
else:
# On the heap
allocator.push_array_on_heap(i)
except AttributeError:
# E.g., a generic SymPy expression
pass
# Introduce declarations on the stack
mapper = dict(allocator.onstack)
iet = Transformer(mapper, nested=True).visit(iet)
# Introduce declarations on the heap (if any)
if allocator.onheap:
decls, allocs, frees = zip(*allocator.onheap)
iet = List(header=decls + allocs, body=iet, footer=frees)
return iet
def find_offloadable_trees(nodes):
"""
Return the trees within ``nodes`` that can be computed by YASK.
A tree is "offloadable to YASK" if it is embedded in a time stepping loop
*and* all of the grids accessed by the enclosed equations are homogeneous
(i.e., same dimensions and data type).
"""
offloadable = []
for tree in retrieve_iteration_tree(nodes):
parallel = filter_iterations(tree, lambda i: i.is_Parallel)
if not parallel:
# Cannot offload non-parallel loops
continue
if not (IsPerfectIteration().visit(tree)
and all(i.is_Expression for i in tree[-1].nodes)):
# Don't know how to offload this Iteration/Expression to YASK
continue
functions = flatten(i.functions for i in tree[-1].nodes)
keys = set((i.grid, i.dtype) for i in functions if i.is_TimeFunction)
if len(keys) == 0:
continue
elif len(keys) > 1:
exit("Cannot handle Operators w/ heterogeneous grids")
grid, dtype = keys.pop()
# Is this a "complete" tree iterating over the entire grid?
dims = [i.dim for i in tree]
if all(i in dims for i in grid.dimensions) and\
any(j in dims for j in [grid.time_dim, grid.stepping_dim]):
offloadable.append((tree, grid, dtype))
return offloadable
def find_offloadable_trees(nodes):
"""
Return the trees within ``nodes`` that can be computed by YASK.
A tree is "offloadable to YASK" if it is embedded in a time stepping loop
*and* all of the grids accessed by the enclosed equations are homogeneous
(i.e., same dimensions, shape, data type).
"""
offloadable = []
for tree in retrieve_iteration_tree(nodes):
parallel = filter_iterations(tree, lambda i: i.is_Parallel)
if not parallel:
# Cannot offload non-parallel loops
continue
if not (IsPerfectIteration().visit(tree)
and all(i.is_Expression for i in tree[-1].nodes)):
# Don't know how to offload this Iteration/Expression to YASK
continue
functions = flatten(i.functions for i in tree[-1].nodes)
keys = set((i.indices, i.shape, i.dtype) for i in functions
if i.is_TimeFunction)
if len(keys) == 0:
continue
elif len(keys) > 1:
exit("Cannot handle Operators w/ heterogeneous grids")
dimensions, shape, dtype = keys.pop()
if len(dimensions) == len(tree) and\
all(i.dim == j for i, j in zip(tree, dimensions)):
# Detected a "full" Iteration/Expression tree (over both
# time and space dimensions)
offloadable.append((tree, dimensions, shape, dtype))
return offloadable
def _ompize(self, nodes, state):
"""
Add OpenMP pragmas to the Iteration/Expression tree to emit parallel code
"""
# Group by outer loop so that we can embed within the same parallel region
was_tagged = False
groups = OrderedDict()
for tree in retrieve_iteration_tree(nodes):
# Determine the number of consecutive parallelizable Iterations
key = lambda i: i.is_Parallel and\
not (i.is_Elementizable or i.is_Vectorizable)
candidates = filter_iterations(tree, key=key, stop='asap')
if not candidates:
was_tagged = False
continue
# Consecutive tagged Iteration go in the same group
is_tagged = any(i.tag is not None for i in tree)
key = len(groups) - (is_tagged & was_tagged)
handle = groups.setdefault(key, OrderedDict())
handle[candidates[0]] = candidates
was_tagged = is_tagged
# Handle parallelizable loops
mapper = OrderedDict()
for group in groups.values():
private = []
for root, tree in group.items():
# Heuristic: if at least two parallel loops are available and the
# physical core count is greater than self.thresholds['collapse'],
# then omp-collapse the loops
nparallel = len(tree)
if psutil.cpu_count(logical=False) < self.thresholds['collapse'] or\
nparallel < 2:
parallel = omplang['for']
else:
parallel = omplang['collapse'](nparallel)
mapper[root] = root._rebuild(pragmas=root.pragmas +
(parallel, ))
# Track the thread-private and thread-shared variables
private.extend([
i for i in FindSymbols('symbolics').visit(root)
if i.is_Array and i._mem_stack
])
# Build the parallel region
private = sorted(set([i.name for i in private]))
private = ('private(%s)' % ','.join(private)) if private else ''
rebuilt = [v for k, v in mapper.items() if k in group]
par_region = Block(header=omplang['par-region'](private),
body=rebuilt)
for k, v in list(mapper.items()):
if isinstance(v, Iteration):
mapper[k] = None if v.is_Remainder else par_region
processed = Transformer(mapper).visit(nodes)
return processed, {}
def iet_insert_C_decls(iet, func_table):
"""
Given an Iteration/Expression tree ``iet``, build a new tree with the
necessary symbol declarations. Declarations are placed as close as
possible to the first symbol use.
:param iet: The input Iteration/Expression tree.
:param func_table: A mapper from callable names to :class:`Callable`s
called from within ``iet``.
"""
# Resolve function calls first
scopes = []
me = MapExpressions()
for k, v in me.visit(iet).items():
if k.is_Call:
func = func_table[k.name]
if func.local:
scopes.extend(me.visit(func.root, queue=list(v)).items())
else:
scopes.append((k, v))
# Determine all required declarations
allocator = Allocator()
mapper = OrderedDict()
for k, v in scopes:
if k.is_scalar:
# Inline declaration
mapper[k] = LocalExpression(**k.args)
elif k.write is None or k.write._mem_external:
# Nothing to do, e.g., variable passed as kernel argument
continue
elif k.write._mem_stack:
# On the stack
key = lambda i: not i.is_Parallel
site = filter_iterations(v, key=key, stop='asap') or [iet]
allocator.push_stack(site[-1], k.write)
else:
# On the heap, as a tensor that must be globally accessible
allocator.push_heap(k.write)
# Introduce declarations on the stack
for k, v in allocator.onstack:
mapper[k] = tuple(Element(i) for i in v)
iet = NestedTransformer(mapper).visit(iet)
for k, v in list(func_table.items()):
if v.local:
func_table[k] = MetaCall(
Transformer(mapper).visit(v.root), v.local)
# Introduce declarations on the heap (if any)
if allocator.onheap:
decls, allocs, frees = zip(*allocator.onheap)
iet = List(header=decls + allocs, body=iet, footer=frees)
return iet
def test_make_efuncs(self, exprs, nfuncs, ntimeiters, nests):
"""Test construction of ElementalFunctions."""
exprs = list(as_tuple(exprs))
grid = Grid(shape=(10, 10))
t = grid.stepping_dim # noqa
x, y = grid.dimensions # noqa
u = Function(name='u', grid=grid) # noqa
v = TimeFunction(name='v', grid=grid) # noqa
# List comprehension would need explicit locals/globals mappings to eval
for i, e in enumerate(list(exprs)):
exprs[i] = eval(e)
op = Operator(exprs)
# We create one ElementalFunction for each Iteration nest over space dimensions
efuncs = []
for n, tree in enumerate(retrieve_iteration_tree(op)):
root = filter_iterations(tree,
key=lambda i: i.dim.is_Space,
stop='asap')
efuncs.append(make_efunc('f%d' % n, root))
assert len(efuncs) == len(nfuncs) == len(ntimeiters) == len(nests)
for efunc, nf, nt, nest in zip(efuncs, nfuncs, ntimeiters, nests):
# Check the `efunc` parameters
assert all(i in efunc.parameters
for i in (x.symbolic_min, x.symbolic_max))
assert all(i in efunc.parameters
for i in (y.symbolic_min, y.symbolic_max))
functions = FindSymbols().visit(efunc)
assert len(functions) == nf
assert all(i in efunc.parameters for i in functions)
timeiters = [
i for i in FindSymbols('free-symbols').visit(efunc)
if i.is_Dimension and i.is_Time
]
assert len(timeiters) == nt
assert all(i in efunc.parameters for i in timeiters)
assert len(efunc.parameters) == 4 + len(functions) + len(timeiters)
# Check there's exactly one ArrayCast for each Function
assert len(FindNodes(ArrayCast).visit(efunc)) == nf
# Check the loop nest structure
trees = retrieve_iteration_tree(efunc)
assert len(trees) == 1
tree = trees[0]
assert all(i.dim.name == j for i, j in zip(tree, nest))
assert efunc.make_call()
def make_parallel(self, iet):
"""
Transform ``iet`` by decorating its parallel :class:`Iteration`s with
suitable ``#pragma omp ...`` for thread-level parallelism.
"""
# Group sequences of loops that should go within the same parallel region
was_tagged = False
groups = OrderedDict()
for tree in retrieve_iteration_tree(iet):
# Determine the number of consecutive parallelizable Iterations
candidates = filter_iterations(tree, key=self.key, stop='asap')
if not candidates:
was_tagged = False
continue
# Consecutive tagged Iteration go in the same group
is_tagged = any(i.tag is not None for i in tree)
key = len(groups) - (is_tagged & was_tagged)
handle = groups.setdefault(key, OrderedDict())
handle[candidates[0]] = candidates
was_tagged = is_tagged
mapper = OrderedDict()
for group in groups.values():
private = []
for root, candidates in group.items():
mapper.update(self._make_parallel_tree(root, candidates))
# Track the thread-private and thread-shared variables
private.extend([
i for i in FindSymbols('symbolics').visit(root)
if i.is_Array and i._mem_stack
])
# Build the parallel region
private = sorted(set([i.name for i in private]))
private = ('private(%s)' % ','.join(private)) if private else ''
rebuilt = [v for k, v in mapper.items() if k in group]
par_region = Block(header=self.lang['par-region'](private),
body=rebuilt)
for k, v in list(mapper.items()):
if isinstance(v, Iteration):
mapper[k] = None if v.is_Remainder else par_region
processed = Transformer(mapper).visit(iet)
# Hack/workaround to the fact that the OpenMP pragmas are not true
# IET nodes, so the `nthreads` variables won't be detected as a
# Callable parameter unless inserted in a mock Expression
if mapper:
nt = NThreads()
eq = LocalExpression(DummyEq(Symbol(name='nt', dtype=np.int32),
nt))
return List(body=[eq, processed]), {'input': [nt]}
else:
return List(body=processed), {}
def _insert_declarations(self, nodes):
"""Populate the Operator's body with the necessary variable declarations."""
# Resolve function calls first
scopes = []
me = MapExpressions()
for k, v in me.visit(nodes).items():
if k.is_Call:
func = self.func_table[k.name]
if func.local:
scopes.extend(me.visit(func.root, queue=list(v)).items())
else:
scopes.append((k, v))
# Determine all required declarations
allocator = Allocator()
mapper = OrderedDict()
for k, v in scopes:
if k.is_scalar:
# Inline declaration
mapper[k] = LocalExpression(**k.args)
elif k.write._mem_external:
# Nothing to do, variable passed as kernel argument
continue
elif k.write._mem_stack:
# On the stack, as established by the DLE
key = lambda i: not i.is_Parallel
site = filter_iterations(v, key=key, stop='asap') or [nodes]
allocator.push_stack(site[-1], k.write)
else:
# On the heap, as a tensor that must be globally accessible
allocator.push_heap(k.write)
# Introduce declarations on the stack
for k, v in allocator.onstack:
mapper[k] = tuple(Element(i) for i in v)
nodes = NestedTransformer(mapper).visit(nodes)
for k, v in list(self.func_table.items()):
if v.local:
self.func_table[k] = FunMeta(
Transformer(mapper).visit(v.root), v.local)
# Introduce declarations on the heap (if any)
if allocator.onheap:
decls, allocs, frees = zip(*allocator.onheap)
nodes = List(header=decls + allocs, body=nodes, footer=frees)
return nodes
def test_make_efuncs(self, exprs, nfuncs, ntimeiters, nests):
"""Test construction of ElementalFunctions."""
exprs = list(as_tuple(exprs))
grid = Grid(shape=(10, 10))
t = grid.stepping_dim # noqa
x, y = grid.dimensions # noqa
u = Function(name='u', grid=grid) # noqa
v = TimeFunction(name='v', grid=grid) # noqa
# List comprehension would need explicit locals/globals mappings to eval
for i, e in enumerate(list(exprs)):
exprs[i] = eval(e)
op = Operator(exprs)
# We create one ElementalFunction for each Iteration nest over space dimensions
efuncs = []
for n, tree in enumerate(retrieve_iteration_tree(op)):
root = filter_iterations(tree, key=lambda i: i.dim.is_Space)[0]
efuncs.append(make_efunc('f%d' % n, root))
assert len(efuncs) == len(nfuncs) == len(ntimeiters) == len(nests)
for efunc, nf, nt, nest in zip(efuncs, nfuncs, ntimeiters, nests):
# Check the `efunc` parameters
assert all(i in efunc.parameters for i in (x.symbolic_min, x.symbolic_max))
assert all(i in efunc.parameters for i in (y.symbolic_min, y.symbolic_max))
functions = FindSymbols().visit(efunc)
assert len(functions) == nf
assert all(i in efunc.parameters for i in functions)
timeiters = [i for i in FindSymbols('free-symbols').visit(efunc)
if isinstance(i, Dimension) and i.is_Time]
assert len(timeiters) == nt
assert all(i in efunc.parameters for i in timeiters)
assert len(efunc.parameters) == 4 + len(functions) + len(timeiters)
# Check the loop nest structure
trees = retrieve_iteration_tree(efunc)
assert len(trees) == 1
tree = trees[0]
assert all(i.dim.name == j for i, j in zip(tree, nest))
assert efunc.make_call()
def make_parallel(self, iet):
"""
Transform ``iet`` by decorating its parallel :class:`Iteration`s with
suitable ``#pragma omp ...`` triggering thread-level parallelism.
"""
# Group sequences of loops that should go within the same parallel region
was_tagged = False
groups = OrderedDict()
for tree in retrieve_iteration_tree(iet):
# Determine the number of consecutive parallelizable Iterations
candidates = filter_iterations(tree, key=self.key, stop='asap')
if not candidates:
was_tagged = False
continue
# Consecutive tagged Iteration go in the same group
is_tagged = any(i.tag is not None for i in tree)
key = len(groups) - (is_tagged & was_tagged)
handle = groups.setdefault(key, OrderedDict())
handle[candidates[0]] = candidates
was_tagged = is_tagged
mapper = OrderedDict()
for group in groups.values():
private = []
for root, candidates in group.items():
mapper.update(self._make_parallel_tree(root, candidates))
# Track the thread-private and thread-shared variables
private.extend([i for i in FindSymbols('symbolics').visit(root)
if i.is_Array and i._mem_stack])
# Build the parallel region
private = sorted(set([i.name for i in private]))
private = ('private(%s)' % ','.join(private)) if private else ''
rebuilt = [v for k, v in mapper.items() if k in group]
par_region = Block(header=self.lang['par-region'](private), body=rebuilt)
for k, v in list(mapper.items()):
if isinstance(v, Iteration):
mapper[k] = None if v.is_Remainder else par_region
return Transformer(mapper).visit(iet)
def _hoist_prodders(self, iet):
"""
Move Prodders within the outer levels of an Iteration tree.
"""
mapper = {}
for tree in retrieve_iteration_tree(iet):
for prodder in FindNodes(Prodder).visit(tree.root):
if prodder._periodic:
try:
key = lambda i: isinstance(i.dim, BlockDimension)
candidate = filter_iterations(tree, key)[-1]
except IndexError:
# Fallback: use the outermost Iteration
candidate = tree.root
mapper[candidate] = candidate._rebuild(nodes=((prodder._rebuild(),) +
candidate.nodes))
mapper[prodder] = None
iet = Transformer(mapper, nested=True).visit(iet)
return iet, {}
def _hoist_prodders(self, iet):
"""
Move Prodders within the outer levels of an Iteration tree.
"""
mapper = {}
for tree in retrieve_iteration_tree(iet):
for prodder in FindNodes(Prodder).visit(tree.root):
if prodder._periodic:
try:
key = lambda i: isinstance(i.dim, BlockDimension)
candidate = filter_iterations(tree, key)[-1]
except IndexError:
# Fallback: use the outermost Iteration
candidate = tree.root
mapper[candidate] = candidate._rebuild(
nodes=(candidate.nodes + (prodder._rebuild(), )))
mapper[prodder] = None
iet = Transformer(mapper, nested=True).visit(iet)
return iet, {}
def make_parallel(self, iet):
"""Transform ``iet`` by introducing shared-memory parallelism."""
mapper = OrderedDict()
for tree in retrieve_iteration_tree(iet):
# Get the first omp-parallelizable Iteration in `tree`
candidates = filter_iterations(tree, key=self.key, stop='asap')
if not candidates:
continue
root = candidates[0]
# Build the `omp-for` tree
partree = self._make_parallel_tree(root, candidates)
# Find out the thread-private and thread-shared variables
private = [
i for i in FindSymbols().visit(partree)
if i.is_Array and i._mem_stack
]
# Build the `omp-parallel` region
private = sorted(set([i.name for i in private]))
private = ('private(%s)' % ','.join(private)) if private else ''
partree = Block(header=self.lang['par-region'](self.nthreads.name,
private),
body=partree)
# Do not enter the parallel region if the step increment might be 0; this
# would raise a `Floating point exception (core dumped)` in some OpenMP
# implementation. Note that using an OpenMP `if` clause won't work
if isinstance(root.step, Symbol):
cond = Conditional(CondEq(root.step, 0),
Element(c.Statement('return')))
partree = List(body=[cond, partree])
mapper[root] = partree
iet = Transformer(mapper).visit(iet)
return iet, {'input': [self.nthreads] if mapper else []}
def __init__(self, expressions, **kwargs):
super(OperatorDebug, self).__init__(expressions, **kwargs)
self._includes.append('stdio.h')
# Minimize the trip count of the sequential loops
iterations = set(flatten(retrieve_iteration_tree(self.body)))
mapper = {
i: i._rebuild(limits=(max(i.offsets) + 2))
for i in iterations if i.is_Sequential
}
self.body = Transformer(mapper).visit(self.body)
# Mark entry/exit points of each non-sequential Iteration tree in the body
iterations = [
filter_iterations(i, lambda i: not i.is_Sequential, 'any')
for i in retrieve_iteration_tree(self.body)
]
iterations = [i[0] for i in iterations if i]
mapper = {
t: List(header=printmark('In nest %d' % i), body=t)
for i, t in enumerate(iterations)
}
self.body = Transformer(mapper).visit(self.body)
def iet_insert_C_decls(iet, func_table=None):
"""
Given an Iteration/Expression tree ``iet``, build a new tree with the
necessary symbol declarations. Declarations are placed as close as
possible to the first symbol use.
:param iet: The input Iteration/Expression tree.
:param func_table: (Optional) a mapper from callable names within ``iet``
to :class:`Callable`s.
"""
func_table = func_table or {}
allocator = Allocator()
mapper = OrderedDict()
# Detect all IET nodes accessing symbols that need to be declared
scopes = []
me = MapExpressions()
for k, v in me.visit(iet).items():
if k.is_Call:
func = func_table.get(k.name)
if func is not None and func.local:
scopes.extend(me.visit(func.root, queue=list(v)).items())
scopes.append((k, v))
# Classify, and then schedule declarations to stack/heap
for k, v in scopes:
if k.is_Expression:
if k.is_scalar:
# Inline declaration
mapper[k] = LocalExpression(**k.args)
continue
objs = [k.write]
elif k.is_Call:
objs = k.params
else:
raise NotImplementedError("Cannot schedule declarations for IET "
"node of type `%s`" % type(k))
for i in objs:
try:
if i.is_LocalObject:
# On the stack
site = v[-1] if v else iet
allocator.push_stack(site, i)
elif i.is_Array:
if i._mem_external:
# Nothing to do; e.g., a user-provided Function
continue
elif i._mem_stack:
# On the stack
key = lambda i: not i.is_Parallel
site = filter_iterations(v, key=key,
stop='asap') or [iet]
allocator.push_stack(site[-1], i)
else:
# On the heap, as a tensor that must be globally accessible
allocator.push_heap(i)
except AttributeError:
# E.g., a generic SymPy expression
pass
# Introduce declarations on the stack
for k, v in allocator.onstack:
mapper[k] = tuple(Element(i) for i in v)
iet = Transformer(mapper, nested=True).visit(iet)
for k, v in list(func_table.items()):
if v.local:
func_table[k] = MetaCall(
Transformer(mapper).visit(v.root), v.local)
# Introduce declarations on the heap (if any)
if allocator.onheap:
decls, allocs, frees = zip(*allocator.onheap)
iet = List(header=decls + allocs, body=iet, footer=frees)
return iet
def iet_insert_C_decls(iet, func_table=None):
"""
Given an Iteration/Expression tree ``iet``, build a new tree with the
necessary symbol declarations. Declarations are placed as close as
possible to the first symbol use.
:param iet: The input Iteration/Expression tree.
:param func_table: (Optional) a mapper from callable names within ``iet``
to :class:`Callable`s.
"""
func_table = func_table or {}
allocator = Allocator()
mapper = OrderedDict()
# First, schedule declarations for Expressions
scopes = []
me = MapExpressions()
for k, v in me.visit(iet).items():
if k.is_Call:
func = func_table.get(k.name)
if func is not None and func.local:
scopes.extend(me.visit(func.root, queue=list(v)).items())
else:
scopes.append((k, v))
for k, v in scopes:
if k.is_scalar:
# Inline declaration
mapper[k] = LocalExpression(**k.args)
elif k.write is None or k.write._mem_external:
# Nothing to do, e.g., variable passed as kernel argument
continue
elif k.write._mem_stack:
# On the stack
key = lambda i: not i.is_Parallel
site = filter_iterations(v, key=key, stop='asap') or [iet]
allocator.push_stack(site[-1], k.write)
else:
# On the heap, as a tensor that must be globally accessible
allocator.push_heap(k.write)
# Then, schedule declarations callables arguments passed by reference/pointer
# (as modified internally by the callable)
scopes = [(k, v) for k, v in me.visit(iet).items() if k.is_Call]
for k, v in scopes:
site = v[-1] if v else iet
for i in k.params:
try:
if i.is_LocalObject:
# On the stack
allocator.push_stack(site, i)
elif i.is_Array:
if i._mem_stack:
# On the stack
allocator.push_stack(site, i)
elif i._mem_heap:
# On the heap
allocator.push_heap(i)
except AttributeError:
# E.g., a generic SymPy expression
pass
# Introduce declarations on the stack
for k, v in allocator.onstack:
mapper[k] = tuple(Element(i) for i in v)
iet = NestedTransformer(mapper).visit(iet)
for k, v in list(func_table.items()):
if v.local:
func_table[k] = MetaCall(Transformer(mapper).visit(v.root), v.local)
# Introduce declarations on the heap (if any)
if allocator.onheap:
decls, allocs, frees = zip(*allocator.onheap)
iet = List(header=decls + allocs, body=iet, footer=frees)
return iet
def _loop_blocking(self, iet):
"""
Apply loop blocking to PARALLEL Iteration trees.
"""
blockinner = bool(self.params.get('blockinner'))
blockalways = bool(self.params.get('blockalways'))
# Make sure loop blocking will span as many Iterations as possible
iet = fold_blockable_tree(iet, blockinner)
mapper = {}
efuncs = []
block_dims = []
for tree in retrieve_iteration_tree(iet):
# Is the Iteration tree blockable ?
iterations = filter_iterations(tree, lambda i: i.is_Parallel)
if not blockinner:
iterations = iterations[:-1]
if len(iterations) <= 1:
continue
root = iterations[0]
if not (tree.root.is_Sequential or iet.is_Callable) and not blockalways:
# Heuristic: avoid polluting the generated code with blocked
# nests (thus increasing JIT compilation time and affecting
# readability) if the blockable tree isn't embedded in a
# sequential loop (e.g., a timestepping loop)
continue
# Apply loop blocking to `tree`
interb = []
intrab = []
for i in iterations:
d = BlockDimension(i.dim, name="%s%d_blk" % (i.dim.name, len(mapper)))
block_dims.append(d)
# Build Iteration over blocks
properties = (PARALLEL,) + ((AFFINE,) if i.is_Affine else ())
interb.append(Iteration([], d, d.symbolic_max, properties=properties))
# Build Iteration within a block
intrab.append(i._rebuild([], limits=(d, d+d.step-1, 1), offsets=(0, 0)))
# Construct the blocked tree
blocked = compose_nodes(interb + intrab + [iterations[-1].nodes])
blocked = unfold_blocked_tree(blocked)
# Promote to a separate Callable
dynamic_parameters = flatten((bi.dim, bi.dim.symbolic_size) for bi in interb)
efunc = make_efunc("bf%d" % len(mapper), blocked, dynamic_parameters)
efuncs.append(efunc)
# Compute the iteration ranges
ranges = []
for i, bi in zip(iterations, interb):
maxb = i.symbolic_max - (i.symbolic_size % bi.dim.step)
ranges.append(((i.symbolic_min, maxb, bi.dim.step),
(maxb + 1, i.symbolic_max, i.symbolic_max - maxb)))
# Build Calls to the `efunc`
body = []
for p in product(*ranges):
dynamic_args_mapper = {}
for bi, (m, M, b) in zip(interb, p):
dynamic_args_mapper[bi.dim] = (m, M)
dynamic_args_mapper[bi.dim.step] = (b,)
call = efunc.make_call(dynamic_args_mapper)
body.append(List(body=call))
mapper[root] = List(body=body)
iet = Transformer(mapper).visit(iet)
return iet, {'dimensions': block_dims, 'efuncs': efuncs,
'args': [i.step for i in block_dims]}
def make_blocking(self, iet):
"""
Apply loop blocking to PARALLEL Iteration trees.
"""
# Make sure loop blocking will span as many Iterations as possible
iet = fold_blockable_tree(iet, self.blockinner)
mapper = {}
efuncs = []
block_dims = []
for tree in retrieve_iteration_tree(iet):
# Is the Iteration tree blockable ?
iterations = filter_iterations(tree, lambda i: i.is_Parallel and i.is_Affine)
if not self.blockinner:
iterations = iterations[:-1]
if len(iterations) <= 1:
continue
root = iterations[0]
if not self.blockalways:
# Heuristically bypass loop blocking if we think `tree`
# won't be computationally expensive. This will help with code
# size/readbility, JIT time, and auto-tuning time
if not (tree.root.is_Sequential or iet.is_Callable):
# E.g., not inside a time-stepping Iteration
continue
if any(i.dim.is_Sub and i.dim.local for i in tree):
# At least an outer Iteration is over a local SubDimension,
# which suggests the computational cost of this Iteration
# nest will be negligible w.r.t. the "core" Iteration nest
# (making use of non-local (Sub)Dimensions only)
continue
if not IsPerfectIteration().visit(root):
# Don't know how to block non-perfect nests
continue
# Apply hierarchical loop blocking to `tree`
level_0 = [] # Outermost level of blocking
level_i = [[] for i in range(1, self.nlevels)] # Inner levels of blocking
intra = [] # Within the smallest block
for i in iterations:
template = "%s%d_blk%s" % (i.dim.name, self.nblocked, '%d')
properties = (PARALLEL,) + ((AFFINE,) if i.is_Affine else ())
# Build Iteration across `level_0` blocks
d = BlockDimension(i.dim, name=template % 0)
level_0.append(Iteration([], d, d.symbolic_max, properties=properties))
# Build Iteration across all `level_i` blocks, `i` in (1, self.nlevels]
for n, li in enumerate(level_i, 1):
di = BlockDimension(d, name=template % n)
li.append(Iteration([], di, limits=(d, d+d.step-1, di.step),
properties=properties))
d = di
# Build Iteration within the smallest block
intra.append(i._rebuild([], limits=(d, d+d.step-1, 1), offsets=(0, 0)))
level_i = flatten(level_i)
# Track all constructed BlockDimensions
block_dims.extend(i.dim for i in level_0 + level_i)
# Construct the blocked tree
blocked = compose_nodes(level_0 + level_i + intra + [iterations[-1].nodes])
blocked = unfold_blocked_tree(blocked)
# Promote to a separate Callable
dynamic_parameters = flatten((l0.dim, l0.step) for l0 in level_0)
dynamic_parameters.extend([li.step for li in level_i])
efunc = make_efunc("bf%d" % self.nblocked, blocked, dynamic_parameters)
efuncs.append(efunc)
# Compute the iteration ranges
ranges = []
for i, l0 in zip(iterations, level_0):
maxb = i.symbolic_max - (i.symbolic_size % l0.step)
ranges.append(((i.symbolic_min, maxb, l0.step),
(maxb + 1, i.symbolic_max, i.symbolic_max - maxb)))
# Build Calls to the `efunc`
body = []
for p in product(*ranges):
dynamic_args_mapper = {}
for l0, (m, M, b) in zip(level_0, p):
dynamic_args_mapper[l0.dim] = (m, M)
dynamic_args_mapper[l0.step] = (b,)
for li in level_i:
if li.dim.root is l0.dim.root:
value = li.step if b is l0.step else b
dynamic_args_mapper[li.step] = (value,)
call = efunc.make_call(dynamic_args_mapper)
body.append(List(body=call))
mapper[root] = List(body=body)
# Next blockable nest, use different (unique) variable/function names
self.nblocked += 1
iet = Transformer(mapper).visit(iet)
# Force-unfold if some folded Iterations haven't been blocked in the end
iet = unfold_blocked_tree(iet)
return iet, {'dimensions': block_dims,
'efuncs': efuncs,
'args': [i.step for i in block_dims]}
def _create_elemental_functions(self, nodes, state):
"""
Extract :class:`Iteration` sub-trees and move them into :class:`Callable`s.
Currently, only tagged, elementizable Iteration objects are targeted.
"""
noinline = self._compiler_decoration('noinline',
c.Comment('noinline?'))
functions = OrderedDict()
mapper = {}
for tree in retrieve_iteration_tree(nodes, mode='superset'):
# Search an elementizable sub-tree (if any)
tagged = filter_iterations(tree, lambda i: i.tag is not None,
'asap')
if not tagged:
continue
root = tagged[0]
if not root.is_Elementizable:
continue
target = tree[tree.index(root):]
# Elemental function arguments
args = [] # Found so far (scalars, tensors)
defined_args = {} # Map of argument values defined by loop bounds
# Build a new Iteration/Expression tree with free bounds
free = []
for i in target:
name, bounds = i.dim.name, i.bounds_symbolic
# Iteration bounds
start = Scalar(name='%s_start' % name, dtype=np.int32)
finish = Scalar(name='%s_finish' % name, dtype=np.int32)
defined_args[start.name] = bounds[0]
defined_args[finish.name] = bounds[1]
# Iteration unbounded indices
ufunc = [
Scalar(name='%s_ub%d' % (name, j), dtype=np.int32)
for j in range(len(i.uindices))
]
defined_args.update(
{uf.name: j.start
for uf, j in zip(ufunc, i.uindices)})
limits = [
Scalar(name=start.name, dtype=np.int32),
Scalar(name=finish.name, dtype=np.int32), 1
]
uindices = [
UnboundedIndex(j.index, i.dim + as_symbol(k))
for j, k in zip(i.uindices, ufunc)
]
free.append(
i._rebuild(limits=limits, offsets=None, uindices=uindices))
# Construct elemental function body, and inspect it
free = NestedTransformer(dict((zip(target, free)))).visit(root)
# Insert array casts for all non-defined
f_symbols = FindSymbols('symbolics').visit(free)
defines = [s.name for s in FindSymbols('defines').visit(free)]
casts = [
ArrayCast(f) for f in f_symbols
if f.is_Tensor and f.name not in defines
]
free = (List(body=casts), free)
for i in derive_parameters(free):
if i.name in defined_args:
args.append((defined_args[i.name], i))
elif i.is_Dimension:
d = Scalar(name=i.name, dtype=i.dtype)
args.append((d, d))
else:
args.append((i, i))
call, params = zip(*args)
name = "f_%d" % root.tag
# Produce the new Call
mapper[root] = List(header=noinline, body=Call(name, call))
# Produce the new Callable
functions.setdefault(
name,
Callable(name, free, 'void', flatten(params), ('static', )))
# Transform the main tree
processed = Transformer(mapper).visit(nodes)
return processed, {'elemental_functions': functions.values()}
def _create_elemental_functions(self, nodes, state):
"""
Extract :class:`Iteration` sub-trees and move them into :class:`Callable`s.
Currently, only tagged, elementizable Iteration objects are targeted.
"""
noinline = self._compiler_decoration('noinline',
c.Comment('noinline?'))
functions = OrderedDict()
mapper = {}
for tree in retrieve_iteration_tree(nodes, mode='superset'):
# Search an elementizable sub-tree (if any)
tagged = filter_iterations(tree, lambda i: i.tag is not None,
'asap')
if not tagged:
continue
root = tagged[0]
if not root.is_Elementizable:
continue
target = tree[tree.index(root):]
# Elemental function arguments
args = [] # Found so far (scalars, tensors)
maybe_required = set() # Scalars that *may* have to be passed in
not_required = set() # Elemental function locally declared scalars
# Build a new Iteration/Expression tree with free bounds
free = []
for i in target:
name, bounds = i.dim.name, i.bounds_symbolic
# Iteration bounds
start = Scalar(name='%s_start' % name, dtype=np.int32)
finish = Scalar(name='%s_finish' % name, dtype=np.int32)
args.extend(zip([ccode(j) for j in bounds], (start, finish)))
# Iteration unbounded indices
ufunc = [
Scalar(name='%s_ub%d' % (name, j), dtype=np.int32)
for j in range(len(i.uindices))
]
args.extend(zip([ccode(j.start) for j in i.uindices], ufunc))
limits = [Symbol(start.name), Symbol(finish.name), 1]
uindices = [
UnboundedIndex(j.index, i.dim + as_symbol(k))
for j, k in zip(i.uindices, ufunc)
]
free.append(
i._rebuild(limits=limits, offsets=None, uindices=uindices))
not_required.update({i.dim}, set(j.index for j in i.uindices))
# Construct elemental function body, and inspect it
free = NestedTransformer(dict((zip(target, free)))).visit(root)
expressions = FindNodes(Expression).visit(free)
fsymbols = FindSymbols('symbolics').visit(free)
# Add all definitely-required arguments
not_required.update({i.output for i in expressions if i.is_scalar})
for i in fsymbols:
if i in not_required:
continue
elif i.is_Array:
args.append(
("(%s*)%s" % (c.dtype_to_ctype(i.dtype), i.name), i))
elif i.is_TensorFunction:
args.append(("%s_vec" % i.name, i))
elif i.is_Scalar:
args.append((i.name, i))
# Add all maybe-required arguments that turn out to be required
maybe_required.update(
set(FindSymbols(mode='free-symbols').visit(free)))
for i in fsymbols:
not_required.update({as_symbol(i), i.indexify()})
for j in i.symbolic_shape:
maybe_required.update(j.free_symbols)
required = filter_sorted(maybe_required - not_required,
key=attrgetter('name'))
args.extend([(i.name, Scalar(name=i.name, dtype=i.dtype))
for i in required])
call, params = zip(*args)
handle = flatten([p.rtargs for p in params])
name = "f_%d" % root.tag
# Produce the new Call
mapper[root] = List(header=noinline, body=Call(name, call))
# Produce the new Callable
functions.setdefault(
name, Callable(name, free, 'void', handle, ('static', )))
# Transform the main tree
processed = Transformer(mapper).visit(nodes)
return processed, {'elemental_functions': functions.values()}
def iet_insert_C_decls(iet, external=None):
"""
Given an IET, build a new tree with the necessary symbol declarations.
Declarations are placed as close as possible to the first symbol occurrence.
Parameters
----------
iet : Node
The input Iteration/Expression tree.
external : tuple, optional
The symbols defined in some outer Callable, which therefore must not
be re-defined.
"""
external = external or []
# Classify and then schedule declarations to stack/heap
allocator = Allocator()
mapper = OrderedDict()
for k, v in MapExpressions().visit(iet).items():
if k.is_Expression:
if k.is_scalar_assign:
# Inline declaration
mapper[k] = LocalExpression(**k.args)
continue
objs = [k.write]
elif k.is_Call:
objs = k.params
for i in objs:
try:
if i.is_LocalObject:
# On the stack
site = v[-1] if v else iet
allocator.push_stack(site, i)
elif i.is_Array:
if i in external:
# The Array is to be defined in some foreign IET
continue
elif i._mem_stack:
# On the stack
key = lambda i: not i.is_Parallel
site = filter_iterations(v, key=key,
stop='asap') or [iet]
allocator.push_stack(site[-1], i)
else:
# On the heap, as a tensor that must be globally accessible
allocator.push_heap(i)
except AttributeError:
# E.g., a generic SymPy expression
pass
# Introduce declarations on the stack
for k, v in allocator.onstack:
mapper[k] = tuple(Element(i) for i in v)
iet = Transformer(mapper, nested=True).visit(iet)
# Introduce declarations on the heap (if any)
if allocator.onheap:
decls, allocs, frees = zip(*allocator.onheap)
iet = List(header=decls + allocs, body=iet, footer=frees)
return iet
def iet_insert_decls(iet, external):
"""
Transform the input IET inserting the necessary symbol declarations.
Declarations are placed as close as possible to the first symbol occurrence.
Parameters
----------
iet : Node
The input Iteration/Expression tree.
external : tuple, optional
The symbols defined in some outer Callable, which therefore must not
be re-defined.
"""
iet = as_tuple(iet)
# Classify and then schedule declarations to stack/heap
allocator = Allocator()
mapper = OrderedDict()
for k, v in MapSections().visit(iet).items():
if k.is_Expression:
if k.is_scalar_assign:
# Inline declaration
mapper[k] = LocalExpression(**k.args)
continue
objs = [k.write]
elif k.is_Call:
objs = k.arguments
for i in objs:
try:
if i.is_LocalObject:
# On the stack
site = v if v else iet
allocator.push_stack(site[-1], i)
elif i.is_Array:
if i in as_tuple(external):
# The Array is defined in some other IET
continue
elif i._mem_stack:
# On the stack
key = lambda i: not i.is_Parallel
site = filter_iterations(v, key=key) or iet
allocator.push_stack(site[-1], i)
else:
# On the heap, as a tensor that must be globally accessible
allocator.push_heap(i)
except AttributeError:
# E.g., a generic SymPy expression
pass
# Introduce declarations on the stack
for k, v in allocator.onstack:
mapper[k] = tuple(Element(i) for i in v)
iet = Transformer(mapper, nested=True).visit(iet)
# Introduce declarations on the heap (if any)
if allocator.onheap:
decls, allocs, frees = zip(*allocator.onheap)
iet = List(header=decls + allocs, body=iet, footer=frees)
return iet
def _loop_blocking(self, iet):
"""
Apply loop blocking to PARALLEL Iteration trees.
"""
blockinner = bool(self.params.get('blockinner'))
blockalways = bool(self.params.get('blockalways'))
# Make sure loop blocking will span as many Iterations as possible
iet = fold_blockable_tree(iet, blockinner)
mapper = {}
efuncs = []
block_dims = []
for tree in retrieve_iteration_tree(iet):
# Is the Iteration tree blockable ?
iterations = filter_iterations(tree, lambda i: i.is_Parallel)
if not blockinner:
iterations = iterations[:-1]
if len(iterations) <= 1:
continue
root = iterations[0]
if not blockalways:
# Heuristically bypass loop blocking if we think `tree`
# won't be computationally expensive. This will help with code
# size/redability, JIT time, and auto-tuning time
if not (tree.root.is_Sequential or iet.is_Callable):
# E.g., not inside a time-stepping Iteration
continue
if any(i.dim.is_Sub and i.dim.local for i in tree):
# At least an outer Iteration is over a local SubDimension,
# which suggests the computational cost of this Iteration
# nest will be negligible w.r.t. the "core" Iteration nest
# (making use of non-local (Sub)Dimensions only)
continue
if not IsPerfectIteration().visit(root):
# Don't know how to block non-perfect nests
continue
# Apply loop blocking to `tree`
interb = []
intrab = []
for i in iterations:
d = BlockDimension(i.dim, name="%s%d_blk" % (i.dim.name, len(mapper)))
block_dims.append(d)
# Build Iteration over blocks
properties = (PARALLEL,) + ((AFFINE,) if i.is_Affine else ())
interb.append(Iteration([], d, d.symbolic_max, properties=properties))
# Build Iteration within a block
intrab.append(i._rebuild([], limits=(d, d+d.step-1, 1), offsets=(0, 0)))
# Construct the blocked tree
blocked = compose_nodes(interb + intrab + [iterations[-1].nodes])
blocked = unfold_blocked_tree(blocked)
# Promote to a separate Callable
dynamic_parameters = flatten((bi.dim, bi.dim.symbolic_size) for bi in interb)
efunc = make_efunc("bf%d" % len(mapper), blocked, dynamic_parameters)
efuncs.append(efunc)
# Compute the iteration ranges
ranges = []
for i, bi in zip(iterations, interb):
maxb = i.symbolic_max - (i.symbolic_size % bi.dim.step)
ranges.append(((i.symbolic_min, maxb, bi.dim.step),
(maxb + 1, i.symbolic_max, i.symbolic_max - maxb)))
# Build Calls to the `efunc`
body = []
for p in product(*ranges):
dynamic_args_mapper = {}
for bi, (m, M, b) in zip(interb, p):
dynamic_args_mapper[bi.dim] = (m, M)
dynamic_args_mapper[bi.dim.step] = (b,)
call = efunc.make_call(dynamic_args_mapper)
body.append(List(body=call))
mapper[root] = List(body=body)
iet = Transformer(mapper).visit(iet)
return iet, {'dimensions': block_dims, 'efuncs': efuncs,
'args': [i.step for i in block_dims]}
def _loop_blocking(self, iet):
"""
Apply loop blocking to PARALLEL Iteration trees.
"""
blockinner = bool(self.params.get('blockinner'))
blockalways = bool(self.params.get('blockalways'))
# Make sure loop blocking will span as many Iterations as possible
iet = fold_blockable_tree(iet, blockinner)
mapper = {}
efuncs = []
block_dims = []
for tree in retrieve_iteration_tree(iet):
# Is the Iteration tree blockable ?
iterations = filter_iterations(tree, lambda i: i.is_Parallel)
if not blockinner:
iterations = iterations[:-1]
if len(iterations) <= 1:
continue
root = iterations[0]
if not (tree.root.is_Sequential
or iet.is_Callable) and not blockalways:
# Heuristic: avoid polluting the generated code with blocked
# nests (thus increasing JIT compilation time and affecting
# readability) if the blockable tree isn't embedded in a
# sequential loop (e.g., a timestepping loop)
continue
# Apply loop blocking to `tree`
interb = []
intrab = []
for i in iterations:
d = BlockDimension(i.dim,
name="%s%d_blk" % (i.dim.name, len(mapper)))
block_dims.append(d)
# Build Iteration over blocks
interb.append(
Iteration([], d, d.symbolic_max, properties=PARALLEL))
# Build Iteration within a block
intrab.append(
i._rebuild([],
limits=(d, d + d.step - 1, 1),
offsets=(0, 0)))
# Construct the blocked tree
blocked = compose_nodes(interb + intrab + [iterations[-1].nodes])
blocked = unfold_blocked_tree(blocked)
# Promote to a separate Callable
dynamic_parameters = flatten(
(bi.dim, bi.dim.symbolic_size) for bi in interb)
efunc = make_efunc("bf%d" % len(mapper), blocked,
dynamic_parameters)
efuncs.append(efunc)
# Compute the iteration ranges
ranges = []
for i, bi in zip(iterations, interb):
maxb = i.symbolic_max - (i.symbolic_size % bi.dim.step)
ranges.append(
((i.symbolic_min, maxb, bi.dim.step),
(maxb + 1, i.symbolic_max, i.symbolic_max - maxb)))
# Build Calls to the `efunc`
body = []
for p in product(*ranges):
dynamic_args_mapper = {}
for bi, (m, M, b) in zip(interb, p):
dynamic_args_mapper[bi.dim] = (m, M)
dynamic_args_mapper[bi.dim.step] = (b, )
call = efunc.make_call(dynamic_args_mapper)
body.append(List(body=call))
mapper[root] = List(body=body)
iet = Transformer(mapper).visit(iet)
return iet, {
'dimensions': block_dims,
'efuncs': efuncs,
'args': [i.step for i in block_dims]
}
def _create_efuncs(self, nodes, state):
"""
Extract Iteration sub-trees and turn them into Calls+Callables.
Currently, only tagged, elementizable Iteration objects are targeted.
"""
noinline = self._compiler_decoration('noinline',
c.Comment('noinline?'))
efuncs = OrderedDict()
mapper = {}
for tree in retrieve_iteration_tree(nodes, mode='superset'):
# Search an elementizable sub-tree (if any)
tagged = filter_iterations(tree, lambda i: i.tag is not None,
'asap')
if not tagged:
continue
root = tagged[0]
if not root.is_Elementizable:
continue
target = tree[tree.index(root):]
# Build a new Iteration/Expression tree with free bounds
free = []
defined_args = {} # Map of argument values defined by loop bounds
for i in target:
name, bounds = i.dim.name, i.symbolic_bounds
# Iteration bounds
_min = Scalar(name='%sf_m' % name,
dtype=np.int32,
is_const=True)
_max = Scalar(name='%sf_M' % name,
dtype=np.int32,
is_const=True)
defined_args[_min.name] = bounds[0]
defined_args[_max.name] = bounds[1]
# Iteration unbounded indices
ufunc = [
Scalar(name='%s_ub%d' % (name, j), dtype=np.int32)
for j in range(len(i.uindices))
]
defined_args.update({
uf.name: j.symbolic_min
for uf, j in zip(ufunc, i.uindices)
})
uindices = [
IncrDimension(j.parent, i.dim + as_symbol(k), 1, j.name)
for j, k in zip(i.uindices, ufunc)
]
free.append(
i._rebuild(limits=(_min, _max, 1),
offsets=None,
uindices=uindices))
# Construct elemental function body
free = Transformer(dict((zip(target, free))),
nested=True).visit(root)
items = FindSymbols().visit(free)
# Insert array casts
casts = [ArrayCast(i) for i in items if i.is_Tensor]
free = List(body=casts + [free])
# Insert declarations
external = [i for i in items if i.is_Array]
free = iet_insert_C_decls(free, external)
# Create the Callable
name = "f_%d" % root.tag
params = derive_parameters(free)
efuncs.setdefault(name,
Callable(name, free, 'void', params, 'static'))
# Create the Call
args = [defined_args.get(i.name, i) for i in params]
mapper[root] = List(header=noinline, body=Call(name, args))
# Transform the main tree
processed = Transformer(mapper).visit(nodes)
return processed, {'efuncs': efuncs.values()}
