Add debug mode to Numba linker

pytensor/link/numba/dispatch/basic.py

@@ -448,16 +448,46 @@
     return opfromgraph
 
 
+def numba_funcify_debug(op, node, **kwargs):
+    numba_fun = numba_funcify(op, node=node, **kwargs)
+
+    if node is None:
+        return numba_fun
+
+    args = ", ".join([f"i{i}" for i in range(len(node.inputs))])
+    str_op = str(op)
+
+    f_source = dedent(
+        f"""
+        def foo({args}):
+            print("\\nOp: ", "{str_op}")
+            print("    inputs: ", {args})
+            outs = numba_fun({args})
+            print("    outputs: ", outs)
+            return outs
+        """
+    )
+
+    f = compile_function_src(
+        f_source,
+        "foo",
+        {**globals(), **{"numba_fun": numba_fun}},
+    )
+
+    return numba_njit(f)
+
+
 @numba_funcify.register(FunctionGraph)
 def numba_funcify_FunctionGraph(
     fgraph,
     node=None,
     fgraph_name="numba_funcified_fgraph",
+    op_conversion_fn=numba_funcify,
     **kwargs,
 ):
     return fgraph_to_python(
         fgraph,
-        numba_funcify,
+        op_conversion_fn=op_conversion_fn,
         type_conversion_fn=numba_typify,
         fgraph_name=fgraph_name,
         **kwargs,

pytensor/link/numba/linker.py

@@ -4,9 +4,17 @@
 class NumbaLinker(JITLinker):
     """A `Linker` that JIT-compiles NumPy-based operations using Numba."""
 
+    def __init__(self, *args, debug: bool = False, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.debug = debug
+
     def fgraph_convert(self, fgraph, **kwargs):
         from pytensor.link.numba.dispatch import numba_funcify
 
+        if self.debug:
+            from pytensor.link.numba.dispatch.basic import numba_funcify_debug
+
+            kwargs.setdefault("op_conversion_fn", numba_funcify_debug)
         return numba_funcify(fgraph, **kwargs)
 
     def jit_compile(self, fn):

tests/link/numba/test_linker.py

@@ -0,0 +1,33 @@
+from textwrap import dedent
+
+import pytest
+
+from pytensor import function
+from pytensor.compile.mode import Mode
+from pytensor.link.numba import NumbaLinker
+from pytensor.tensor import vector
+
+
+pytest.importorskip("numba")
+
+
+def test_debug_mode(capsys):
+    x = vector("x")
+    y = (x + 1).sum()
+
+    debug_mode = Mode(linker=NumbaLinker(debug=True))
+    fn = function([x], y, mode=debug_mode)
+
+    assert fn([0, 1]) == 3.0
+    captured = capsys.readouterr()
+    assert captured.out == dedent(
+        """
+        Op:  Add
+            inputs:  [1.] [0. 1.]
+            outputs:  [1. 2.]
+
+        Op:  Sum{axes=None}
+            inputs:  [1. 2.]
+            outputs:  3.0
+        """
+    )