Structuring arguments in gen_candidates_torch (#3019)

Summary:

Structuring the optimizer and stopping_criterion arguments in gen_candidates_torch.

Fixes #2994.

Differential Revision: D82839737

Author: Carl Hvarfner

botorch/generation/gen.py

@@ -532,7 +532,9 @@ def gen_candidates_torch(
         optimizer (Optimizer): The pytorch optimizer to use to perform
             candidate search.
         options: Options used to control the optimization. Includes
-            maxiter: Maximum number of iterations
+            optimizer_options: Dict of additional options to pass to the optimizer
+                (e.g. lr, weight_decay)
+            stopping_criterion_options: Dict of options for the stopping criterion.
         callback: A callback function accepting the current iteration, loss,
             and gradients as arguments. This function is executed after computing
             the loss and gradients, but before calling the optimizer.
@@ -580,11 +582,17 @@ def gen_candidates_torch(
             [i for i in range(clamped_candidates.shape[-1]) if i not in fixed_features],
         ]
     clamped_candidates = clamped_candidates.requires_grad_(True)
-    _optimizer = optimizer(params=[clamped_candidates], lr=options.get("lr", 0.025))
+
+    # Extract optimizer-specific options from the options dict
+    optimizer_options = options.pop("optimizer_options", {})
+    stopping_criterion_options = options.pop("stopping_criterion_options", {})
+
+    optimizer_options["lr"] = optimizer_options.get("lr", 0.025)
+    _optimizer = optimizer(params=[clamped_candidates], **optimizer_options)
 
     i = 0
     stop = False
-    stopping_criterion = ExpMAStoppingCriterion(**options)
+    stopping_criterion = ExpMAStoppingCriterion(**stopping_criterion_options)
     while not stop:
         i += 1
         with torch.no_grad():

test/generation/test_gen.py

@@ -324,6 +324,37 @@ def test_gen_candidates_torch_timeout_behavior(self):
         self.assertFalse(any(issubclass(w.category, OptimizationWarning) for w in ws))
         self.assertTrue("Optimization timed out" in logs.output[-1])
 
+    def test_gen_candidates_torch_optimizer_with_optimizer_args(self):
+        """Test that Adam optimizer is created with the correct learning rate."""
+        self._setUp(double=False)
+        qEI = qExpectedImprovement(self.model, best_f=self.f_best)
+
+        # Create a mock optimizer class
+        mock_optimizer_class = mock.MagicMock()
+        mock_optimizer_instance = mock.MagicMock()
+        mock_optimizer_class.return_value = mock_optimizer_instance
+
+        gen_candidates_torch(
+            initial_conditions=self.initial_conditions,
+            acquisition_function=qEI,
+            lower_bounds=0,
+            upper_bounds=1,
+            optimizer=mock_optimizer_class,  # Pass the mock optimizer directly
+            options={
+                "optimizer_options": {"lr": 0.02, "weight_decay": 1e-5},
+                "stopping_criterion_options": {"maxiter": 1},
+            },
+        )
+
+        # Verify that the optimizer was called with the correct arguments
+        mock_optimizer_class.assert_called_once()
+        call_args = mock_optimizer_class.call_args
+        # Check that params argument is present
+        self.assertIn("params", call_args.kwargs)
+        # Check optimizer options
+        self.assertEqual(call_args.kwargs["lr"], 0.02)
+        self.assertEqual(call_args.kwargs["weight_decay"], 1e-5)
+
     def test_gen_candidates_scipy_warns_opt_no_res(self):
         ckwargs = {"dtype": torch.float, "device": self.device}