Add external nested SDFG capabilities

dace/sdfg/nodes.py

@@ -545,6 +545,8 @@ class NestedSDFG(CodeNode):
 
     # NOTE: We cannot use SDFG as the type because of an import loop
     sdfg = SDFGReferenceProperty(desc="The SDFG", allow_none=True)
+    ext_sdfg_path = Property(dtype=str, default=None, allow_none=True,
+                             desc='Path to a file containing the SDFG for this nested SDFG')
     schedule = EnumProperty(dtype=dtypes.ScheduleType,
                             desc="SDFG schedule",
                             allow_none=True,
@@ -569,22 +571,30 @@ class NestedSDFG(CodeNode):
 
     def __init__(self,
                  label,
-                 sdfg,
+                 sdfg: Optional['dace.SDFG'],
                  inputs: Set[str],
                  outputs: Set[str],
                  symbol_mapping: Dict[str, Any] = None,
                  schedule=dtypes.ScheduleType.Default,
                  location=None,
-                 debuginfo=None):
-        from dace.sdfg import SDFG
+                 debuginfo=None,
+                 path: Optional[str] = None):
         super(NestedSDFG, self).__init__(label, location, inputs, outputs)
 
         # Properties
-        self.sdfg: SDFG = sdfg
+        self.sdfg: 'dace.SDFG' = sdfg
+        self.ext_sdfg_path = path
         self.symbol_mapping = symbol_mapping or {}
         self.schedule = schedule
         self.debuginfo = debuginfo
 
+    def load_external(self, context: Optional['dace.SDFGState']) -> None:
+        if self.sdfg is None and self.ext_sdfg_path is not None:
+            self.sdfg = dace.SDFG.from_file(self.ext_sdfg_path)
+            self.sdfg.parent_nsdfg_node = self
+            self.sdfg.parent = context
+            self.sdfg.parent_sdfg = context.sdfg if context else None
+
     def __deepcopy__(self, memo):
         cls = self.__class__
         result = cls.__new__(cls)
@@ -607,14 +617,14 @@ def from_json(json_obj, context=None):
 
         dace.serialize.set_properties_from_json(ret, json_obj, context)
 
-        if context and 'sdfg_state' in context:
-            ret.sdfg.parent = context['sdfg_state']
-        if context and 'sdfg' in context:
-            ret.sdfg.parent_sdfg = context['sdfg']
-
-        ret.sdfg.parent_nsdfg_node = ret
+        if ret.sdfg is not None:
+            if context and 'sdfg_state' in context:
+                ret.sdfg.parent = context['sdfg_state']
+            if context and 'sdfg' in context:
+                ret.sdfg.parent_sdfg = context['sdfg']
+            ret.sdfg.parent_nsdfg_node = ret
 
-        ret.sdfg.update_cfg_list([])
+            ret.sdfg.update_cfg_list([])
 
         return ret
 
@@ -664,28 +674,29 @@ def validate(self, sdfg, state, references: Optional[Set[int]] = None, **context
         for out_conn in self.out_connectors:
             if not dtypes.validate_name(out_conn):
                 raise NameError('Invalid output connector "%s"' % out_conn)
-        if self.sdfg.parent_nsdfg_node is not self:
-            raise ValueError('Parent nested SDFG node not properly set')
-        if self.sdfg.parent is not state:
-            raise ValueError('Parent state not properly set for nested SDFG node')
-        if self.sdfg.parent_sdfg is not sdfg:
-            raise ValueError('Parent SDFG not properly set for nested SDFG node')
-
-        connectors = self.in_connectors.keys() | self.out_connectors.keys()
-        for conn in connectors:
-            if conn in self.sdfg.symbols:
-                raise ValueError(
-                    f'Connector "{conn}" was given, but it refers to a symbol, which is not allowed. '
-                    'To pass symbols use "symbol_mapping".')
-            if conn not in self.sdfg.arrays:
-                raise NameError(
-                    f'Connector "{conn}" was given but is not a registered data descriptor in the nested SDFG. '
-                    'Example: parameter passed to a function without a matching array within it.')
-        for dname, desc in self.sdfg.arrays.items():
-            if not desc.transient and dname not in connectors:
-                raise NameError('Data descriptor "%s" not found in nested SDFG connectors' % dname)
-            if dname in connectors and desc.transient:
-                raise NameError('"%s" is a connector but its corresponding array is transient' % dname)
+        if self.sdfg:
+            if self.sdfg.parent_nsdfg_node is not self:
+                raise ValueError('Parent nested SDFG node not properly set')
+            if self.sdfg.parent is not state:
+                raise ValueError('Parent state not properly set for nested SDFG node')
+            if self.sdfg.parent_sdfg is not sdfg:
+                raise ValueError('Parent SDFG not properly set for nested SDFG node')
+
+            connectors = self.in_connectors.keys() | self.out_connectors.keys()
+            for conn in connectors:
+                if conn in self.sdfg.symbols:
+                    raise ValueError(
+                        f'Connector "{conn}" was given, but it refers to a symbol, which is not allowed. '
+                        'To pass symbols use "symbol_mapping".')
+                if conn not in self.sdfg.arrays:
+                    raise NameError(
+                        f'Connector "{conn}" was given but is not a registered data descriptor in the nested SDFG. '
+                        'Example: parameter passed to a function without a matching array within it.')
+            for dname, desc in self.sdfg.arrays.items():
+                if not desc.transient and dname not in connectors:
+                    raise NameError('Data descriptor "%s" not found in nested SDFG connectors' % dname)
+                if dname in connectors and desc.transient:
+                    raise NameError('"%s" is a connector but its corresponding array is transient' % dname)
 
         # Validate inout connectors
         from dace.sdfg import utils  # Avoids circular import
@@ -706,17 +717,18 @@ def validate(self, sdfg, state, references: Optional[Set[int]] = None, **context
                                  f"output ({outputs}) arrays")
 
         # Validate undefined symbols
-        symbols = set(k for k in self.sdfg.free_symbols if k not in connectors)
-        missing_symbols = [s for s in symbols if s not in self.symbol_mapping]
-        if missing_symbols:
-            raise ValueError('Missing symbols on nested SDFG: %s' % (missing_symbols))
-        extra_symbols = self.symbol_mapping.keys() - symbols
-        if len(extra_symbols) > 0:
-            # TODO: Elevate to an error?
-            warnings.warn(f"{self.label} maps to unused symbol(s): {extra_symbols}")
-
-        # Recursively validate nested SDFG
-        self.sdfg.validate(references, **context)
+        if self.sdfg:
+            symbols = set(k for k in self.sdfg.free_symbols if k not in connectors)
+            missing_symbols = [s for s in symbols if s not in self.symbol_mapping]
+            if missing_symbols:
+                raise ValueError('Missing symbols on nested SDFG: %s' % (missing_symbols))
+            extra_symbols = self.symbol_mapping.keys() - symbols
+            if len(extra_symbols) > 0:
+                # TODO: Elevate to an error?
+                warnings.warn(f"{self.label} maps to unused symbol(s): {extra_symbols}")
+
+            # Recursively validate nested SDFG
+            self.sdfg.validate(references, **context)
 
 
 # ------------------------------------------------------------------------------

dace/sdfg/sdfg.py

@@ -2341,6 +2341,10 @@ def compile(self, output_file=None, validate=True,
             # if the codegen modifies the SDFG (thereby changing its hash)
             sdfg.build_folder = build_folder
 
+            # Ensure external nested SDFGs are loaded.
+            for _ in sdfg.all_sdfgs_recursive(load_ext=True):
+                pass
+
             # Rename SDFG to avoid runtime issues with clashing names
             index = 0
             while sdfg.is_loaded():

dace/sdfg/state.py

@@ -350,7 +350,7 @@ def edges(self) -> List[MultiConnectorEdge[mm.Memlet]]:
     def all_nodes_recursive(self, predicate = None) -> Iterator[Tuple[NodeT, GraphT]]:
         for node in self.nodes():
             yield node, self
-            if isinstance(node, nd.NestedSDFG):
+            if isinstance(node, nd.NestedSDFG) and node.sdfg:
                 if predicate is None or predicate(node, self):
                     yield from node.sdfg.all_nodes_recursive(predicate)
 
@@ -1380,7 +1380,7 @@ def add_node(self, node):
         if not isinstance(node, nd.Node):
             raise TypeError("Expected Node, got " + type(node).__name__ + " (" + str(node) + ")")
         # Correct nested SDFG's parent attributes
-        if isinstance(node, nd.NestedSDFG):
+        if isinstance(node, nd.NestedSDFG) and node.sdfg is not None:
             node.sdfg.parent = self
             node.sdfg.parent_sdfg = self.sdfg
             node.sdfg.parent_nsdfg_node = node
@@ -1667,7 +1667,7 @@ def add_tasklet(
 
     def add_nested_sdfg(
         self,
-        sdfg: 'SDFG',
+        sdfg: Optional['SDFG'],
         parent,
         inputs: Union[Set[str], Dict[str, dtypes.typeclass]],
         outputs: Union[Set[str], Dict[str, dtypes.typeclass]],
@@ -1676,16 +1676,21 @@ def add_nested_sdfg(
         schedule=dtypes.ScheduleType.Default,
         location=None,
         debuginfo=None,
+        external_path: Optional[str] = None,
     ):
         """ Adds a nested SDFG to the SDFG state. """
         if name is None:
             name = sdfg.label
         debuginfo = _getdebuginfo(debuginfo or self._default_lineinfo)
 
-        sdfg.parent = self
-        sdfg.parent_sdfg = self.sdfg
+        if sdfg is None and external_path is None:
+            raise ValueError('Neither an SDFG nor an external SDFG path has been provided')
+
+        if sdfg is not None:
+            sdfg.parent = self
+            sdfg.parent_sdfg = self.sdfg
 
-        sdfg.update_cfg_list([])
+            sdfg.update_cfg_list([])
 
         # Make dictionary of autodetect connector types from set
         if isinstance(inputs, (set, collections.abc.KeysView)):
@@ -1702,35 +1707,37 @@ def add_nested_sdfg(
             schedule=schedule,
             location=location,
             debuginfo=debuginfo,
+            path=external_path,
         )
         self.add_node(s)
 
-        sdfg.parent_nsdfg_node = s
-
-        # Add "default" undefined symbols if None are given
-        symbols = sdfg.free_symbols
-        if symbol_mapping is None:
-            symbol_mapping = {s: s for s in symbols}
-            s.symbol_mapping = symbol_mapping
-
-        # Validate missing symbols
-        missing_symbols = [s for s in symbols if s not in symbol_mapping]
-        if missing_symbols and parent:
-            # If symbols are missing, try to get them from the parent SDFG
-            parent_mapping = {s: s for s in missing_symbols if s in parent.symbols}
-            symbol_mapping.update(parent_mapping)
-            s.symbol_mapping = symbol_mapping
-            missing_symbols = [s for s in symbols if s not in symbol_mapping]
-        if missing_symbols:
-            raise ValueError('Missing symbols on nested SDFG "%s": %s' % (name, missing_symbols))
+        if sdfg is not None:
+            sdfg.parent_nsdfg_node = s
 
-        # Add new global symbols to nested SDFG
-        from dace.codegen.tools.type_inference import infer_expr_type
-        for sym, symval in s.symbol_mapping.items():
-            if sym not in sdfg.symbols:
-                # TODO: Think of a better way to avoid calling
-                # symbols_defined_at in this moment
-                sdfg.add_symbol(sym, infer_expr_type(symval, self.sdfg.symbols) or dtypes.typeclass(int))
+            # Add "default" undefined symbols if None are given
+            symbols = sdfg.free_symbols
+            if symbol_mapping is None:
+                symbol_mapping = {s: s for s in symbols}
+                s.symbol_mapping = symbol_mapping
+
+            # Validate missing symbols
+            missing_symbols = [s for s in symbols if s not in symbol_mapping]
+            if missing_symbols and parent:
+                # If symbols are missing, try to get them from the parent SDFG
+                parent_mapping = {s: s for s in missing_symbols if s in parent.symbols}
+                symbol_mapping.update(parent_mapping)
+                s.symbol_mapping = symbol_mapping
+                missing_symbols = [s for s in symbols if s not in symbol_mapping]
+            if missing_symbols:
+                raise ValueError('Missing symbols on nested SDFG "%s": %s' % (name, missing_symbols))
+
+            # Add new global symbols to nested SDFG
+            from dace.codegen.tools.type_inference import infer_expr_type
+            for sym, symval in s.symbol_mapping.items():
+                if sym not in sdfg.symbols:
+                    # TODO: Think of a better way to avoid calling
+                    # symbols_defined_at in this moment
+                    sdfg.add_symbol(sym, infer_expr_type(symval, self.sdfg.symbols) or dtypes.typeclass(int))
 
         return s
 
@@ -2818,23 +2825,27 @@ def add_state_after(self,
     ###################################################################
     # Traversal methods
 
-    def all_control_flow_regions(self, recursive=False) -> Iterator['ControlFlowRegion']:
+    def all_control_flow_regions(self, recursive=False, load_ext=False) -> Iterator['ControlFlowRegion']:
         """ Iterate over this and all nested control flow regions. """
         yield self
         for block in self.nodes():
             if isinstance(block, SDFGState) and recursive:
                 for node in block.nodes():
                     if isinstance(node, nd.NestedSDFG):
-                        yield from node.sdfg.all_control_flow_regions(recursive=recursive)
+                        if node.sdfg:
+                            yield from node.sdfg.all_control_flow_regions(recursive=recursive, load_ext=load_ext)
+                        elif load_ext:
+                            node.load_external(block)
+                            yield from node.sdfg.all_control_flow_regions(recursive=recursive, load_ext=load_ext)
             elif isinstance(block, ControlFlowRegion):
-                yield from block.all_control_flow_regions(recursive=recursive)
+                yield from block.all_control_flow_regions(recursive=recursive, load_ext=load_ext)
             elif isinstance(block, ConditionalBlock):
                 for _, branch in block.branches:
-                    yield from branch.all_control_flow_regions(recursive=recursive)
+                    yield from branch.all_control_flow_regions(recursive=recursive, load_ext=load_ext)
 
-    def all_sdfgs_recursive(self) -> Iterator['SDFG']:
+    def all_sdfgs_recursive(self, load_ext=False) -> Iterator['SDFG']:
         """ Iterate over this and all nested SDFGs. """
-        for cfg in self.all_control_flow_regions(recursive=True):
+        for cfg in self.all_control_flow_regions(recursive=True, load_ext=load_ext):
             if isinstance(cfg, dace.SDFG):
                 yield cfg
 

dace/transformation/passes/fusion_inline.py

@@ -106,7 +106,7 @@ def modifies(self) -> ppl.Modifies:
     def apply_pass(self, sdfg: SDFG, _: Dict[str, Any]) -> Optional[int]:
         modified = 0
         for node, state in sdfg.all_nodes_recursive():
-            if not isinstance(node, nodes.NestedSDFG):
+            if not isinstance(node, nodes.NestedSDFG) or node.sdfg is None:
                 continue
             was_modified = False
             if node.sdfg.parent_nsdfg_node is not node:

tests/nested_sdfg_test.py

@@ -1,4 +1,6 @@
-# Copyright 2019-2021 ETH Zurich and the DaCe authors. All rights reserved.
+# Copyright 2019-2024 ETH Zurich and the DaCe authors. All rights reserved.
+import os
+import tempfile
 import numpy as np
 
 import dace as dp
@@ -54,5 +56,58 @@ def do():
     assert diff <= 1e-5
 
 
+def test_external_nsdfg():
+    N = dp.symbol('N')
+
+    @dp.program
+    def sdfg_internal(input: dp.float32, output: dp.float32[1]):
+        @dp.tasklet
+        def init():
+            out >> output
+            out = input
+
+        for k in range(4):
+
+            @dp.tasklet
+            def do():
+                oin << output
+                out >> output
+                out = oin * input
+
+
+    # Construct SDFG
+    mysdfg = SDFG('outer_sdfg')
+    state = mysdfg.add_state()
+    A = state.add_array('A', [N, N], dp.float32)
+    B = state.add_array('B', [N, N], dp.float32)
+
+    map_entry, map_exit = state.add_map('elements', [('i', '0:N'), ('j', '0:N')])
+    internal = sdfg_internal.to_sdfg()
+    fd, filename = tempfile.mkstemp(suffix='.sdfg')
+    internal.save(filename)
+    nsdfg = state.add_nested_sdfg(None, mysdfg, {'input'}, {'output'}, name='sdfg_internal', external_path=filename)
+
+    # Add edges
+    state.add_memlet_path(A, map_entry, nsdfg, dst_conn='input', memlet=Memlet.simple(A, 'i,j'))
+    state.add_memlet_path(nsdfg, map_exit, B, src_conn='output', memlet=Memlet.simple(B, 'i,j'))
+
+
+    N = 64
+
+    input = dp.ndarray([N, N], dp.float32)
+    output = dp.ndarray([N, N], dp.float32)
+    input[:] = np.random.rand(N, N).astype(dp.float32.type)
+    output[:] = dp.float32(0)
+
+    mysdfg(A=input, B=output, N=N)
+
+    diff = np.linalg.norm(output - np.power(input, 5)) / (N * N)
+    print("Difference:", diff)
+    assert diff <= 1e-5
+
+    os.close(fd)
+
+
 if __name__ == "__main__":
     test()
+    test_external_nsdfg()