Add pt.analysis.get_num_call_sites

pytato/analysis/__init__.py

@@ -31,9 +31,11 @@ from pytato.array import (Array, IndexLambda, Stack, Concatenate, Einsum,
                           DictOfNamedArrays, NamedArray,
                           IndexBase, IndexRemappingBase, InputArgumentBase,
                           ShapeType)
+from pytato.function import FunctionDefinition, Call
 from pytato.transform import Mapper, ArrayOrNames, CachedWalkMapper
 from pytato.loopy import LoopyCall
 from pymbolic.mapper.optimize import optimize_mapper
+from pytools import memoize_method
 
 if TYPE_CHECKING:
     from pytato.distributed.nodes import DistributedRecv, DistributedSendRefHolder
@@ -47,6 +49,8 @@ __doc__ = """
 
 .. autofunction:: get_num_nodes
 
+.. autofunction:: get_num_call_sites
+
 .. autoclass:: DirectPredecessorsGetter
 """
 
@@ -388,3 +392,57 @@ def get_num_nodes(outputs: Union[Array, DictOfNamedArrays]) -> int:
     return ncm.count
 
 # }}}
+
+
+# {{{ CallSiteCountMapper
+
+@optimize_mapper(drop_args=True, drop_kwargs=True, inline_get_cache_key=True)
+class CallSiteCountMapper(CachedWalkMapper):
+    """
+    Counts the number of :class:`~pytato.Call` nodes in a DAG.
+
+    .. attribute:: count
+
+       The number of nodes.
+    """
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.count = 0
+
+    # type-ignore-reason: dropped the extra `*args, **kwargs`.
+    def get_cache_key(self, expr: ArrayOrNames) -> int:  # type: ignore[override]
+        return id(expr)
+
+    @memoize_method
+    def map_function_definition(self, /, expr: FunctionDefinition,
+                                *args: Any, **kwargs: Any) -> None:
+        if not self.visit(expr):
+            return
+
+        new_mapper = self.clone_for_callee()
+        for subexpr in expr.returns.values():
+            new_mapper(subexpr, *args, **kwargs)
+
+        self.count += new_mapper.count
+
+        self.post_visit(expr, *args, **kwargs)
+
+    # type-ignore-reason: dropped the extra `*args, **kwargs`.
+    def post_visit(self, expr: Any) -> None:  # type: ignore[override]
+        if isinstance(expr, Call):
+            self.count += 1
+
+
+def get_num_call_sites(outputs: Union[Array, DictOfNamedArrays]) -> int:
+    """Returns the number of nodes in DAG *outputs*."""
+
+    from pytato.codegen import normalize_outputs
+    outputs = normalize_outputs(outputs)
+
+    cscm = CallSiteCountMapper()
+    cscm(outputs)
+
+    return cscm.count
+
+# }}}