Dynamically allocate contact and efc_ arrays on a new memory arena.

- Add private function `mj_arenaAlloc`. This is used internally to allocate memory from the arena.

- Add private function `mj_nefc` to count constraints. This function returns a tight upper bound on `d->nefc`. The number of counted constraints can be slightly bigger than exact `d->nefc` in the case of constraints with empty Jacobian, as when placing a frictional tendon between two world sites.

- Add new `memory` attribute to the `size` XML element for specification of arena memory size. This attribute is mutually exclusive with `nstack` and `njmax` specifications, which are now deprecated (but left around for the time being for legacy compatibility).

- Move `d->stack` to the end of the new arena space. The stack now grows in reverse from the end.

PiperOrigin-RevId: 479341539
Change-Id: I27f67d524607db71e24f714dc96b221c0448795e

Author: saran-t

dm_control/composer/initializers/prop_initializer_test.py

@@ -20,10 +20,8 @@
 from dm_control import composer
 from dm_control import mjcf
 from dm_control.composer.initializers import prop_initializer
-from dm_control.composer.variation import deterministic
 from dm_control.composer.variation import distributions
 from dm_control.entities import props
-from dm_control.rl import control
 import numpy as np
 
 
@@ -158,62 +156,6 @@ def test_ignore_contacts_with_entities(self):
                        ignore_contacts_with_entities=None)
     self.assertNoContactsInvolvingEntities(physics, spheres)
 
-  def test_exception_if_contact_buffer_always_full(self):
-    max_attempts_per_prop = 2
-    radius = 0.1
-    num_spheres = 5
-    physics, spheres = _make_spheres(num_spheres=num_spheres,
-                                     radius=radius, nconmax=1)
-
-    candidate_positions = np.multiply.outer(
-        np.arange(num_spheres * max_attempts_per_prop), [radius * 2.01, 0, 0])
-
-    # If we only place the first sphere then the others will all be overlapping
-    # at the origin, so we get an error due to filling the contact buffer.
-    prop_placer_failure = prop_initializer.PropPlacer(
-        props=[spheres[0]],
-        position=deterministic.Sequence(candidate_positions),
-        ignore_collisions=False,
-        max_attempts_per_prop=max_attempts_per_prop)
-    with self.assertRaises(control.PhysicsError):
-      prop_placer_failure(physics, random_state=np.random.RandomState(0))
-
-    physics, spheres = _make_spheres(num_spheres=num_spheres,
-                                     radius=radius, nconmax=1)
-
-    # If we place all of the spheres then we can find a configuration where they
-    # are non-colliding, so the contact buffer is not full when the initializer
-    # returns.
-    prop_placer = prop_initializer.PropPlacer(
-        props=spheres,
-        position=deterministic.Sequence(candidate_positions),
-        ignore_collisions=False,
-        max_attempts_per_prop=max_attempts_per_prop)
-    prop_placer(physics, random_state=np.random.RandomState(0))
-
-  def test_no_exception_if_contact_buffer_transiently_full(self):
-    max_attempts_per_prop = 2
-    radius = 0.1
-    num_spheres = 3
-    physics, spheres = _make_spheres(num_spheres=num_spheres,
-                                     radius=radius, nconmax=1)
-    fixed_positions = [[-radius * 1.01, 0., 0],
-                       [radius * 1.01, 0., 0.]]
-    for sphere, position in zip(spheres[:2], fixed_positions):
-      sphere.set_pose(physics, position=position)
-
-    candidate_positions = [
-        [0., 0., 0.],  # Collides with both fixed spheres.
-        [5 * radius, 0., 0.]]  # Does not collide with either sphere.
-
-    # The first candidate position transiently fills the contact buffer.
-    prop_placer = prop_initializer.PropPlacer(
-        props=spheres[2:],
-        position=deterministic.Sequence(candidate_positions),
-        ignore_collisions=False,
-        max_attempts_per_prop=max_attempts_per_prop)
-    prop_placer(physics, random_state=np.random.RandomState(0))
-
   @parameterized.parameters([False, True])
   def test_settle_physics(self, settle_physics):
     radius = 0.1

dm_control/locomotion/soccer/task.py

@@ -45,7 +45,7 @@ def __init__(
       observables=None,
       disable_walker_contacts=False,
       nconmax_per_player=200,
-      njmax_per_player=200,
+      njmax_per_player=400,
       control_timestep=0.025,
       tracking_cameras=(),
   ):
@@ -229,7 +229,7 @@ def __init__(self,
                observables=None,
                disable_walker_contacts=False,
                nconmax_per_player=200,
-               njmax_per_player=200,
+               njmax_per_player=400,
                control_timestep=0.025,
                tracking_cameras=()):
     """See base class."""

dm_control/mujoco/wrapper/core_test.py

@@ -24,7 +24,6 @@
 from dm_control import _render
 from dm_control.mujoco.testing import assets
 from dm_control.mujoco.wrapper import core
-import mock
 import mujoco
 import numpy as np
 
@@ -92,11 +91,7 @@ def testLoadXML(self):
     # simulation step.
     model = core.MjModel.from_xml_string(xml_with_warning)
     data = core.MjData(model)
-    with mock.patch.object(core, "logging") as mock_logging:
-      mujoco.mj_step(model.ptr, data.ptr)
-    mock_logging.warning.assert_called_once_with(
-        "Pre-allocated constraint buffer is full. Increase njmax above 2. "
-        "Time = 0.0000.")
+    mujoco.mj_step(model.ptr, data.ptr)
 
   def testLoadXMLWithAssetsFromString(self):
     core.MjModel.from_xml_string(MODEL_WITH_ASSETS, assets=ASSETS)