Files
Mujoco_WASM/mjx/mujoco/mjx/_src/support_test.py
T
Baruch Tabanpour 6cfea71985 Allow for different MJX backend implementations.
PiperOrigin-RevId: 755935704
Change-Id: Ic135cd00137c2857c73c683ed9fdc5ac4418715d
2025-05-07 11:28:39 -07:00

748 lines
24 KiB
Python

# Copyright 2023 DeepMind Technologies Limited
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Tests for support."""
from absl.testing import absltest
from absl.testing import parameterized
import jax
from jax import numpy as jp
import mujoco
from mujoco import mjx
from mujoco.mjx._src import support
from mujoco.mjx._src import test_util
import numpy as np
class SupportTest(parameterized.TestCase):
def test_mul_m(self):
m = test_util.load_test_file('pendula.xml')
# first test sparse
m.opt.jacobian = mujoco.mjtJacobian.mjJAC_SPARSE
d = mujoco.MjData(m)
# give the system a little kick to ensure we have non-identity rotations
d.qvel = np.random.random(m.nv)
mujoco.mj_step(m, d, 10) # let dynamics get state significantly non-zero
mujoco.mj_forward(m, d)
mx = mjx.put_model(m)
dx = mjx.put_data(m, d)
vec = np.random.random(m.nv)
mjx_vec = jax.jit(mjx.mul_m)(mx, dx, jp.array(vec))
mj_vec = np.zeros(m.nv)
mujoco.mj_mulM(m, d, mj_vec, vec)
np.testing.assert_allclose(mjx_vec, mj_vec, atol=5e-5, rtol=5e-5)
# also check dense
m.opt.jacobian = mujoco.mjtJacobian.mjJAC_DENSE
mujoco.mj_forward(m, d)
mx = mjx.put_model(m)
dx = mjx.put_data(m, d)
mjx_vec = jax.jit(mjx.mul_m)(mx, dx, jp.array(vec))
np.testing.assert_allclose(mjx_vec, mj_vec, atol=5e-5, rtol=5e-5)
def test_full_m(self):
m = test_util.load_test_file('pendula.xml')
# for the model to be sparse to exercise MJX full_M
m.opt.jacobian = mujoco.mjtJacobian.mjJAC_SPARSE
d = mujoco.MjData(m)
# give the system a little kick to ensure we have non-identity rotations
d.qvel = np.random.random(m.nv)
mujoco.mj_step(m, d, 10) # let dynamics get state significantly non-zero
mx = mjx.put_model(m)
dx = mjx.put_data(m, d)
mjx_full_m = jax.jit(support.full_m)(mx, dx)
mj_full_m = np.zeros((m.nv, m.nv), dtype=np.float64)
mujoco.mj_fullM(m, mj_full_m, d.qM)
np.testing.assert_allclose(mjx_full_m, mj_full_m, atol=5e-5, rtol=5e-5)
@parameterized.parameters('constraints.xml', 'pendula.xml')
def test_jac(self, fname):
np.random.seed(0)
m = test_util.load_test_file(fname)
d = mujoco.MjData(m)
mujoco.mj_step(m, d)
mx = mjx.put_model(m)
dx = mjx.put_data(m, d)
point = np.random.randn(3)
body = np.random.choice(m.nbody)
jacp, jacr = jax.jit(support.jac)(mx, dx, point, body)
jacp_expected, jacr_expected = np.zeros((3, m.nv)), np.zeros((3, m.nv))
mujoco.mj_jac(m, d, jacp_expected, jacr_expected, point, body)
np.testing.assert_almost_equal(jacp, jacp_expected.T, 6)
np.testing.assert_almost_equal(jacr, jacr_expected.T, 6)
def test_xfrc_accumulate(self):
"""Tests that xfrc_accumulate ouput matches mj_xfrcAccumulate."""
np.random.seed(0)
m = test_util.load_test_file('pendula.xml')
d = mujoco.MjData(m)
mujoco.mj_step(m, d)
mx = mjx.put_model(m)
dx = mjx.put_data(m, d)
self.assertFalse((dx.xipos == 0.0).all())
xfrc = np.random.rand(*dx.xfrc_applied.shape)
d.xfrc_applied[:] = xfrc
dx = dx.replace(xfrc_applied=jp.array(xfrc))
qfrc = jax.jit(support.xfrc_accumulate)(mx, dx)
qfrc_expected = np.zeros(m.nv)
for i in range(1, m.nbody):
mujoco.mj_applyFT(
m,
d,
d.xfrc_applied[i, :3],
d.xfrc_applied[i, 3:],
d.xipos[i],
i,
qfrc_expected,
)
np.testing.assert_almost_equal(qfrc, qfrc_expected, 6)
def test_custom(self):
xml = """
<mujoco model="right_shadow_hand">
<custom>
<numeric data="15" name="max_contact_points"/>
<numeric data="42" name="max_geom_pairs"/>
</custom>
</mujoco>
"""
m = mujoco.MjModel.from_xml_string(xml)
def _get_numeric(m, name):
id_ = support.name2id(m, mujoco.mjtObj.mjOBJ_NUMERIC, name)
return int(m.numeric_data[id_]) if id_ >= 0 else -1
self.assertEqual(_get_numeric(m, 'something'), -1)
self.assertEqual(_get_numeric(m, 'max_contact_points'), 15)
self.assertEqual(_get_numeric(m, 'max_geom_pairs'), 42)
mx = mjx.put_model(m)
self.assertEqual(_get_numeric(mx, 'something'), -1)
self.assertEqual(_get_numeric(mx, 'max_contact_points'), 15)
self.assertEqual(_get_numeric(mx, 'max_geom_pairs'), 42)
def test_names_and_ids(self):
m = test_util.load_test_file('pendula.xml')
mx = mjx.put_model(m)
nums = {
mujoco.mjtObj.mjOBJ_JOINT: m.njnt,
mujoco.mjtObj.mjOBJ_GEOM: m.ngeom,
mujoco.mjtObj.mjOBJ_BODY: m.nbody,
}
for obj in nums:
names = [mujoco.mj_id2name(m, obj.value, i) for i in range(nums[obj])]
for i, n in enumerate(names):
self.assertEqual(support.id2name(mx, obj, i), n)
i = i if n is not None else -1
self.assertEqual(support.name2id(mx, obj, n), i)
def test_bind(self):
xml = """
<mujoco model="test_bind_model">
<worldbody>
<body pos="10 20 30" name="body1">
<joint axis="1 0 0" type="ball" name="joint1"/>
<geom size="1 2 3" type="box" name="geom1" pos="0 1 0"/>
</body>
<body pos="40 50 60" name="body2">
<joint axis="0 1 0" type="slide" name="joint2"/>
<geom size="4 5 6" type="box" name="geom2"/>
</body>
<body pos="70 80 90" name="body3">
<joint axis="0 0 1" type="slide" name="joint3"/>
<geom size="7 8 9" type="box" name="geom3"/>
</body>
</worldbody>
<actuator>
<motor joint="joint1"/>
<motor joint="joint2"/>
<motor joint="joint3"/>
</actuator>
<sensor>
<framepos objtype="body" objname="body1"/>
<framepos objtype="body" objname="body2"/>
<framepos objtype="body" objname="body3"/>
</sensor>
</mujoco>
"""
s = mujoco.MjSpec.from_string(xml)
m = s.compile()
d = mujoco.MjData(m)
mx = mjx.put_model(m)
dx = mjx.put_data(m, d)
mujoco.mj_step(m, d)
dx = mjx.step(mx, dx)
# test getting
np.testing.assert_array_equal(mx.bind(s.bodies).pos, m.body_pos)
np.testing.assert_array_equal(dx.bind(mx, s.bodies).xpos, d.xpos)
np.testing.assert_array_equal(m.bind(s.bodies[0]).mass, m.body_mass[0])
np.testing.assert_array_equal(m.bind(s.bodies[0:1]).mass, [m.body_mass[0]])
np.testing.assert_array_equal(mx.bind(s.bodies[0]).mass, m.body_mass[0])
np.testing.assert_array_equal(mx.bind(s.bodies[0:1]).mass, [m.body_mass[0]])
for i in range(m.nbody):
np.testing.assert_array_equal(m.bind(s.bodies[i]).pos, m.body_pos[i, :])
np.testing.assert_array_equal(mx.bind(s.bodies[i]).pos, m.body_pos[i, :])
np.testing.assert_array_equal(d.bind(s.bodies[i]).xpos, d.xpos[i, :])
np.testing.assert_array_equal(
dx.bind(mx, s.bodies[i]).xpos, d.xpos[i, :]
)
np.testing.assert_array_equal(
dx.bind(mx, s.bodies[i]).xfrc_applied, d.xfrc_applied[i, :]
)
np.testing.assert_array_equal(mx.bind(s.geoms).size, m.geom_size)
np.testing.assert_array_equal(dx.bind(mx, s.geoms).xpos, d.geom_xpos)
for i in range(m.ngeom):
np.testing.assert_array_equal(m.bind(s.geoms[i]).size, m.geom_size[i, :])
np.testing.assert_array_equal(mx.bind(s.geoms[i]).size, m.geom_size[i, :])
np.testing.assert_array_equal(d.bind(s.geoms[i]).xpos, d.geom_xpos[i, :])
np.testing.assert_array_equal(
dx.bind(mx, s.geoms[i]).xpos, d.geom_xpos[i, :]
)
np.testing.assert_array_equal(mx.bind(s.joints).axis, m.jnt_axis)
np.testing.assert_array_equal(mx.bind(s.joints).qposadr, m.jnt_qposadr)
np.testing.assert_array_equal(mx.bind(s.joints).dofadr, m.jnt_dofadr)
np.testing.assert_array_equal(dx.bind(mx, s.joints[1]).id, 1)
np.testing.assert_array_equal(dx.bind(mx, s.joints[1:2]).id, [1])
qposnum = [4, 1, 1] # one ball joint (4) and two slide joints (1)
dofnum = [3, 1, 1] # one ball joint (3) and two slide joints (1)
for i in range(m.njnt):
np.testing.assert_array_equal(m.bind(s.joints[i]).axis, m.jnt_axis[i, :])
np.testing.assert_array_equal(mx.bind(s.joints[i]).axis, m.jnt_axis[i, :])
np.testing.assert_array_almost_equal(
dx.bind(mx, s.joints[i]).qpos,
d.qpos[m.jnt_qposadr[i]:m.jnt_qposadr[i] + qposnum[i]], decimal=6
)
np.testing.assert_array_almost_equal(
dx.bind(mx, s.joints[i]).qvel,
d.qvel[m.jnt_dofadr[i]:m.jnt_dofadr[i] + dofnum[i]], decimal=6
)
np.testing.assert_array_almost_equal(
dx.bind(mx, s.joints[i]).qacc,
d.qacc[m.jnt_dofadr[i]:m.jnt_dofadr[i] + dofnum[i]], decimal=6
)
np.testing.assert_array_equal(dx.bind(mx, s.actuators).ctrl, d.ctrl)
for i in range(m.nu):
np.testing.assert_array_equal(d.bind(s.actuators[i]).ctrl, d.ctrl[i])
np.testing.assert_array_equal(
dx.bind(mx, s.actuators[i]).ctrl, d.ctrl[i]
)
np.testing.assert_array_equal(
dx.bind(mx, s.sensors).sensordata, d.sensordata
)
for i in range(m.nsensor):
np.testing.assert_array_equal(
dx.bind(mx, s.sensors[i]).sensordata,
d.sensordata[m.sensor_adr[i] : m.sensor_adr[i] + m.sensor_dim[i]],
)
# test setting
np.testing.assert_array_equal(d.ctrl, [0, 0, 0])
np.testing.assert_array_equal(dx.bind(mx, s.actuators).ctrl, d.ctrl)
dx2 = dx.bind(mx, s.actuators).set('ctrl', [1, 2, 3])
np.testing.assert_array_equal(dx2.bind(mx, s.actuators).ctrl, [1, 2, 3])
np.testing.assert_array_equal(dx.bind(mx, s.actuators).ctrl, [0, 0, 0])
dx3 = dx.bind(mx, s.actuators[1:]).set('ctrl', [4, 5])
np.testing.assert_array_equal(dx3.bind(mx, s.actuators).ctrl, [0, 4, 5])
np.testing.assert_array_equal(dx.bind(mx, s.actuators).ctrl, [0, 0, 0])
dx4 = dx.bind(mx, s.actuators[1]).set('ctrl', [6])
np.testing.assert_array_equal(dx4.bind(mx, s.actuators).ctrl, [0, 6, 0])
np.testing.assert_array_equal(dx.bind(mx, s.actuators).ctrl, [0, 0, 0])
dx5 = dx.bind(mx, s.actuators[1]).set('ctrl', 7)
np.testing.assert_array_equal(dx5.bind(mx, s.actuators).ctrl, [0, 7, 0])
np.testing.assert_array_equal(dx.bind(mx, s.actuators).ctrl, [0, 0, 0])
qpos_1step = [1.00000e00, -3.67875e-06, 0, 0, 0, -3.924e-05]
qpos_desired = [1, 0, 0, 0, 0, 8]
np.testing.assert_array_almost_equal(d.qpos, qpos_1step)
np.testing.assert_array_almost_equal(dx.bind(mx, s.joints).qpos, d.qpos)
dx6 = dx.bind(mx, s.joints[::2]).set('qpos', [1, 0, 0, 0, 8])
np.testing.assert_array_equal(dx6.bind(mx, s.joints).qpos, qpos_desired)
np.testing.assert_array_almost_equal(dx.bind(mx, s.joints).qpos, d.qpos)
dx6a = dx.bind(mx, s.joints[0]).set('qpos', qpos_desired[:4])
np.testing.assert_array_equal(
dx6a.bind(mx, s.joints[0]).qpos, qpos_desired[:4]
)
dx7 = dx.bind(mx, s.joints[::2]).set('qvel', [2.0, -1.2, 0.5, 0.3])
np.testing.assert_array_almost_equal(
dx7.bind(mx, s.joints).qvel, [2.0, -1.2, 0.5, 0.0, 0.3], decimal=6
)
dx8 = dx.bind(mx, s.joints[::2]).set('qacc', [3.0, -2.1, 0.6, 0.4])
np.testing.assert_array_almost_equal(
dx8.bind(mx, s.joints).qacc, [3.0, -2.1, 0.6, 0.0, 0.4], decimal=6
)
dx9 = dx.bind(mx, s.bodies[1]).set('xfrc_applied', [1, 2, 3, 4, 5, 6])
np.testing.assert_array_equal(
dx9.bind(mx, s.bodies[1]).xfrc_applied, [1, 2, 3, 4, 5, 6]
)
for body in s.bodies[:1] + s.bodies[2:]:
np.testing.assert_array_equal(
dx7.bind(mx, body).xfrc_applied, [0, 0, 0, 0, 0, 0]
)
# test attribute and type mismatches
with self.assertRaisesRegex(
AttributeError, 'ctrl is not available for this type'
):
print(dx.bind(mx, s.geoms).ctrl)
with self.assertRaises(KeyError):
print(dx.bind(mx, s.actuators).actuator_ctrl)
with self.assertRaisesRegex(
AttributeError,
"'Data' object has no attribute 'actuator_actuator_ctrl'",
):
print(dx.bind(mx, s.actuators).set('actuator_ctrl', [1, 2, 3]))
with self.assertRaisesRegex(
AttributeError, 'qpos, qvel, qacc are not available for this type'
):
print(dx.bind(mx, s.geoms).qpos)
# test that modified names do not raise an error
s.actuators[0].name = 'modified_actuator_name'
np.testing.assert_array_equal(dx.bind(mx, s.actuators).ctrl, d.ctrl)
s.geoms[0].name = 'modified_geom_name'
np.testing.assert_array_equal(mx.bind(s.geoms[0]).pos, m.geom_pos[0, :])
# test batched data
batch_size = 16
ds = [d for _ in range(batch_size)]
vdx = jax.vmap(lambda xpos: dx.replace(xpos=xpos))(
jp.array([d.xpos for d in ds], device=jax.devices('cpu')[0]))
for i in range(m.nbody):
np.testing.assert_array_equal(
vdx.bind(mx, s.bodies[i]).xpos, [d.xpos[i, :]] * batch_size
)
# test that adding a body requires recompilation
s.worldbody.add_body()
with self.assertRaises(ValueError) as e:
mx.bind(s.bodies)
self.assertEqual(
str(e.exception),
'mjSpec signature does not match mjx.Model signature:'
' 17856615236057737915 != 12517827274439268436',
)
_CONTACTS = """
<mujoco>
<worldbody>
<body pos="0 0 0.55" euler="1 0 0">
<joint axis="1 0 0" type="free"/>
<geom fromto="-0.4 0 0 0.4 0 0" size="0.05" type="capsule" condim="6"/>
</body>
<body pos="0 0 0.5" euler="0 1 0">
<joint axis="1 0 0" type="free"/>
<geom fromto="-0.4 0 0 0.4 0 0" size="0.05" type="capsule" condim="3"/>
</body>
<body pos="0 0 0.445" euler="0 90 0">
<joint axis="1 0 0" type="free"/>
<geom fromto="-0.4 0 0 0.4 0 0" size="0.05" type="capsule" condim="1"/>
</body>
</worldbody>
</mujoco>
"""
def test_contact_force(self):
m = mujoco.MjModel.from_xml_string(self._CONTACTS)
d = mujoco.MjData(m)
mujoco.mj_step(m, d)
assert (
np.unique(d.contact.geom).shape[0] == 3
), 'This test assumes all capsule are in contact.'
mx = mjx.put_model(m)
dx = mjx.put_data(m, d)
mujoco.mj_step(m, d)
dx = mjx.step(mx, dx)
# map MJX contacts to MJ ones
def _find(g):
val = (g == dx._impl.contact.geom).sum(axis=1)
return np.where(val == 2)[0][0]
contact_id_map = {i: _find(d.contact.geom[i]) for i in range(d.ncon)}
for i in range(d.ncon):
result = np.zeros(6, dtype=float)
mujoco.mj_contactForce(m, d, i, result)
j = contact_id_map[i]
force = jax.jit(support.contact_force, static_argnums=(2,))(mx, dx, j)
np.testing.assert_allclose(result, force, rtol=1e-5, atol=2)
# check for zeros after first condim elements
condim = dx._impl.contact.dim[j]
if condim < 6:
np.testing.assert_allclose(force[condim:], 0, rtol=1e-5, atol=1e-5)
# test world conversion
force = jax.jit(
support.contact_force,
static_argnums=(
2,
3,
),
)(mx, dx, j, True)
# back to contact frame
force = force.at[:3].set(dx._impl.contact.frame[j] @ force[:3])
force = force.at[3:].set(dx._impl.contact.frame[j] @ force[3:])
np.testing.assert_allclose(result, force, rtol=1e-5, atol=2)
def test_wrap_inside(self):
maxiter = 5
tolerance = 1.0e-4
z_init = 1.0 - 1.0e-5
# len0 <= radius
np.testing.assert_equal(
support.wrap_inside(
jp.array([1.0, 0, 0, 0]),
jp.array([1.0]),
maxiter,
tolerance,
z_init,
)[0],
jp.array([-1]),
)
# len1 <= radius
np.testing.assert_equal(
support.wrap_inside(
jp.array([0, 0, 1.0, 0]),
jp.array([1.0]),
maxiter,
tolerance,
z_init,
)[0],
jp.array([-1]),
)
# radius < mjMINVAL
np.testing.assert_equal(
support.wrap_inside(
jp.array([1, 0, 0, 1]), jp.array([0.1 * mujoco.mjMINVAL]), maxiter,
tolerance,
z_init,
)[0],
jp.array([-1]),
)
# len0 < mjMINVAL and radius < mjMINVAL
np.testing.assert_equal(
support.wrap_inside(
jp.array([0.1 * mujoco.mjMINVAL, 0, 0, 0]),
jp.array([0.1 * mujoco.mjMINVAL]),
maxiter,
tolerance,
z_init,
)[0],
jp.array([-1]),
)
# len1 < mjMINVAL and radius < mjMINVAL
np.testing.assert_equal(
support.wrap_inside(
jp.array([0, 0, 0.1 * mujoco.mjMINVAL, 0]),
jp.array([0.1 * mujoco.mjMINVAL]),
maxiter,
tolerance,
z_init,
)[0],
jp.array([-1]),
)
# wrap: p0 = [1, 0], p1 = [0, 1]
status, pnt = support.wrap_inside(
jp.array([1, 0, 0, 1]), jp.array([0.5]), maxiter, tolerance, z_init
)
np.testing.assert_allclose(
pnt,
jp.array([0.353553, 0.353553, 0.353553, 0.353553]),
atol=1e-3,
rtol=1e-3,
)
np.testing.assert_equal(status, jp.array([0]))
# no wrap, point on circle: p0 = [1, 0], p1 = [0, 0.5]
status, pnt = support.wrap_inside(
jp.array([1, 0, 0, 0.5]), jp.array([0.5]), maxiter, tolerance, z_init
)
np.testing.assert_allclose(
pnt,
jp.zeros(4),
atol=1e-3,
rtol=1e-3,
)
np.testing.assert_equal(status, jp.array([-1]))
# no wrap, segment-circle intersection: p0 = [0.75, 0], p1 = [0, 0.51]
status, pnt = support.wrap_inside(
jp.array([0.75, 0, 0, 0.51]),
jp.array([0.5]),
maxiter,
tolerance,
z_init,
)
np.testing.assert_allclose(
pnt,
jp.zeros(4),
atol=1e-3,
rtol=1e-3,
)
np.testing.assert_equal(status, jp.array([-1]))
# wrap: p0 = [-0.5, 1], p1 = [0.5, 1]
status, pnt = support.wrap_inside(
jp.array([-0.5, 1, 0.5, 1]),
jp.array([0.5]),
maxiter,
tolerance,
z_init,
)
np.testing.assert_allclose(
pnt,
jp.array([0, 0.5, 0, 0.5]),
atol=1e-3,
rtol=1e-3,
)
np.testing.assert_equal(status, jp.array([0]))
# TODO(taylorhowell): improve wrap_inside testing with additional test cases
def test_muscle_gain_length(self):
lmin = 0.5
lmax = 1.5
np.testing.assert_allclose(
support.muscle_gain_length(0, lmin, lmax),
jp.zeros(1),
rtol=1e-5,
atol=1e-5,
)
np.testing.assert_allclose(
support.muscle_gain_length(0.5, lmin, lmax),
jp.zeros(1),
rtol=1e-5,
atol=1e-5,
)
np.testing.assert_allclose(
support.muscle_gain_length(0.6, lmin, lmax),
jp.array([0.08]),
rtol=1e-5,
atol=1e-5,
)
np.testing.assert_allclose(
support.muscle_gain_length(0.75, lmin, lmax),
jp.array([0.5]),
rtol=1e-5,
atol=1e-5,
)
np.testing.assert_allclose(
support.muscle_gain_length(1.0, lmin, lmax),
jp.ones(1),
rtol=1e-5,
atol=1e-5,
)
np.testing.assert_allclose(
support.muscle_gain_length(1.25, lmin, lmax),
jp.array([0.5]),
rtol=1e-5,
atol=1e-5,
)
np.testing.assert_allclose(
support.muscle_gain_length(1.5, lmin, lmax),
jp.zeros(1),
rtol=1e-5,
atol=1e-5,
)
np.testing.assert_allclose(
support.muscle_gain_length(2.0, lmin, lmax),
jp.zeros(1),
rtol=1e-5,
atol=1e-5,
)
def test_muscle_gain(self):
length = jp.array([1.0])
lengthrange = jp.array([0.0, 1.0])
acc0 = jp.array([1.0])
prm = jp.array([0.0, 1.0, 1.0, 200.0, 0.5, 3.0, 1.0, 0.0, 2.0, 0.0])
# V <= -1
vel = jp.array([-1.5])
np.testing.assert_allclose(
support.muscle_gain(length, vel, lengthrange, acc0, prm),
jp.array([-0.0]),
rtol=1e-5,
atol=1e-5,
)
# V <= 0
vel = jp.array([-0.5])
np.testing.assert_allclose(
support.muscle_gain(length, vel, lengthrange, acc0, prm),
jp.array([-0.25]),
rtol=1e-5,
atol=1e-5,
)
# V <= y
vel = jp.array([0.5])
np.testing.assert_allclose(
support.muscle_gain(length, vel, lengthrange, acc0, prm),
jp.array([-1.75]),
rtol=1e-5,
atol=1e-5,
)
# V > y
vel = jp.array([1.5])
np.testing.assert_allclose(
support.muscle_gain(length, vel, lengthrange, acc0, prm),
jp.array([-2.0]),
rtol=1e-5,
atol=1e-5,
)
# force < 0
prm = prm.at[2].set(-1.0)
np.testing.assert_allclose(
support.muscle_gain(length, vel, lengthrange, acc0, prm),
jp.array([-400.0]),
rtol=1e-5,
atol=1e-5,
)
def test_muscle_bias(self):
lengthrange = jp.array([0.0, 1.0])
acc0 = jp.array([1.0])
prm = jp.array([0.0, 1.0, 1.0, 200.0, 0.5, 3.0, 1.5, 1.3, 1.2, 0.0])
# L <= 1
length = jp.array([0.5])
np.testing.assert_allclose(
support.muscle_bias(length, lengthrange, acc0, prm),
jp.array([0.0]),
rtol=1e-5,
atol=1e-5,
)
# L <= b
length = jp.array([1.5])
np.testing.assert_allclose(
support.muscle_bias(length, lengthrange, acc0, prm),
jp.array([-0.1625]),
rtol=1e-5,
atol=1e-5,
)
# L > b
length = jp.array([2.5])
np.testing.assert_allclose(
support.muscle_bias(length, lengthrange, acc0, prm),
jp.array([-1.3]),
rtol=1e-5,
atol=1e-5,
)
# force < 0
prm = prm.at[2].set(-1.0)
np.testing.assert_allclose(
support.muscle_bias(length, lengthrange, acc0, prm),
jp.array([-260.0]),
rtol=1e-5,
atol=1e-5,
)
def test_smooth_muscle_dynamics(self):
# compute time constant as in Millard et al. (2013)
# https://doi.org/10.1115/1.4023390
def _muscle_dynamics_millard(ctrl, act, prm):
ctrlclamp = jp.clip(ctrl, 0, 1)
actclamp = jp.clip(act, 0, 1)
tau0 = prm[0] * (0.5 + 1.5 * actclamp)
tau1 = prm[1] / (0.5 + 1.5 * actclamp)
tau = jp.where(ctrlclamp > act, tau0, tau1)
return (ctrlclamp - act) / jp.maximum(mujoco.mjMINVAL, tau)
prm = jp.array([0.01, 0.04, 0.0])
# exact equality if tau_smooth = 0
for ctrl in [-0.1, 0.0, 0.4, 0.5, 1.0, 1.0]:
for act in [-0.1, 0.0, 0.4, 0.5, 1.0, 1.1]:
actdot_old = _muscle_dynamics_millard(ctrl, act, prm)
actdot_new = support.muscle_dynamics(ctrl, act, prm)
np.testing.assert_allclose(actdot_old, actdot_new, rtol=1e-5, atol=1e-5)
# positive tau_smooth
tau_smooth = 0.2
prm = prm.at[2].set(tau_smooth)
act = 0.5
eps = 1.0e-6
ctrl = 0.4 - eps # smaller than act by just over 0.5 * tau_smooth
np.testing.assert_allclose(
_muscle_dynamics_millard(ctrl, act, prm),
support.muscle_dynamics(ctrl, act, prm),
rtol=1e-5,
atol=1e-5,
)
ctrl = 0.6 + eps # larger than act by just over 0.5 * tau_smooth
np.testing.assert_allclose(
_muscle_dynamics_millard(ctrl, act, prm),
support.muscle_dynamics(ctrl, act, prm),
rtol=1e-5,
atol=1e-5,
)
# right in the middle should give average of time constants
tau_act = 0.2
tau_deact = 0.3
for dctrl in [0.0, 0.1, 0.2, 1.0, 1.1]:
lower = support.muscle_dynamics_timescale(
-dctrl, tau_act, tau_deact, tau_smooth
)
upper = support.muscle_dynamics_timescale(
dctrl, tau_act, tau_deact, tau_smooth
)
np.testing.assert_allclose(
0.5 * (upper + lower),
0.5 * (tau_act + tau_deact),
rtol=1e-5,
atol=1e-5,
)
if __name__ == '__main__':
absltest.main()