Add customizable number of points in simple runner. (#484)

Co-authored-by: wkrokosz <w.krasnicki@cent.uw.edu.pl>
Co-authored-by: Bas Nijholt <bas@nijho.lt>

Author: 3 people

adaptive/learner/learner2D.py

@@ -817,7 +817,7 @@ def remove_unfinished(self) -> None:
             if p not in self.data:
                 self._stack[p] = np.inf
 
-    def plot(self, n=None, tri_alpha=0):
+    def plot(self, n=None, tri_alpha=0.0):
         r"""Plot the Learner2D's current state.
 
         This plot function interpolates the data on a regular grid.

adaptive/runner.py

@@ -911,11 +911,12 @@ def simple(
     npoints_goal: int | None = None,
     end_time_goal: datetime | None = None,
     duration_goal: timedelta | int | float | None = None,
+    points_per_ask: int = 1,
 ):
     """Run the learner until the goal is reached.
 
-    Requests a single point from the learner, evaluates
-    the function to be learned, and adds the point to the
+    Requests points from the learner, evaluates
+    the function to be learned, and adds the points to the
     learner, until the goal is reached, blocking the current
     thread.
 
@@ -946,6 +947,9 @@ def simple(
         calculation. Stop when the current time is larger or equal than
         ``start_time + duration_goal``. ``duration_goal`` can be a number
         indicating the number of seconds.
+    points_per_ask : int, optional
+        The number of points to ask for between every interpolation rerun. Defaults
+        to 1, which can introduce significant overhead on long runs.
     """
     goal = _goal(
         learner,
@@ -958,7 +962,7 @@ def simple(
     )
     assert goal is not None
     while not goal(learner):
-        xs, _ = learner.ask(1)
+        xs, _ = learner.ask(points_per_ask)
         for x in xs:
             y = learner.function(x)
             learner.tell(x, y)

adaptive/tests/test_runner.py

@@ -201,3 +201,65 @@ def test_auto_goal():
     simple(learner, auto_goal(duration=1e-2, learner=learner))
     t_end = time.time()
     assert t_end - t_start >= 1e-2
+
+
+def test_simple_points_per_ask():
+    """Test that the simple runner respects the points_per_ask parameter (PR #484)."""
+
+    def f(x):
+        return x**2
+
+    # Test with 1D learner asking for multiple points at once
+    learner1 = Learner1D(f, (-1, 1))
+    simple(learner1, npoints_goal=20, points_per_ask=5)
+    assert learner1.npoints >= 20
+
+    # Test with 2D learner
+    def f2d(xy):
+        x, y = xy
+        return x**2 + y**2
+
+    learner2 = Learner2D(f2d, ((-1, 1), (-1, 1)))
+    simple(learner2, npoints_goal=32, points_per_ask=8)
+    assert learner2.npoints >= 32
+
+    # Test that default behavior (points_per_ask=1) is preserved
+    learner3 = Learner1D(f, (-1, 1))
+    simple(learner3, npoints_goal=15)
+    assert learner3.npoints >= 15
+
+    # Test performance improvement: more points per ask = fewer ask calls
+    ask_count = 0
+    original_ask = Learner1D.ask
+
+    def counting_ask(self, n, tell_pending=True):
+        nonlocal ask_count
+        ask_count += 1
+        return original_ask(self, n, tell_pending)
+
+    # Monkey patch to count ask calls
+    Learner1D.ask = counting_ask
+
+    try:
+        # Test with points_per_ask=1 (default)
+        learner4 = Learner1D(f, (-1, 1))
+        ask_count = 0
+        simple(learner4, npoints_goal=10, points_per_ask=1)
+        ask_count_single = ask_count
+
+        # Test with points_per_ask=5
+        learner5 = Learner1D(f, (-1, 1))
+        ask_count = 0
+        simple(learner5, npoints_goal=10, points_per_ask=5)
+        ask_count_batch = ask_count
+
+        # When asking for 5 points at a time, we should have fewer ask calls
+        assert ask_count_batch < ask_count_single
+
+        # Both learners should have reached their goal
+        assert learner4.npoints >= 10
+        assert learner5.npoints >= 10
+
+    finally:
+        # Restore original method
+        Learner1D.ask = original_ask