def test_find_element(self): xml_str = """ <root> <option name='option_name'> <content></content> </option> <world name='world_name'> <geom name='geom_name'/> </world> </root>""" tree = xml_tools.parse(six.StringIO(xml_str)) world = xml_tools.find_element(root=tree, tag='world', name='world_name') self.assertEqual(world.tag, 'world') self.assertEqual(world.attrib['name'], 'world_name') geom = xml_tools.find_element(root=tree, tag='geom', name='geom_name') self.assertEqual(geom.tag, 'geom') self.assertEqual(geom.attrib['name'], 'geom_name') with self.assertRaisesRegexp(ValueError, 'Element with tag'): xml_tools.find_element(root=tree, tag='does_not_exist', name='name') with self.assertRaisesRegexp(ValueError, 'Element with tag'): xml_tools.find_element(root=tree, tag='world', name='does_not_exist')
def test_tostring(self): xml_str = """ <root> <head> <content></content> </head> </root>""" tree = xml_tools.parse(io.StringIO(xml_str)) self.assertEqual(b'<root>\n <head>\n <content/>\n </head>\n</root>\n', etree.tostring(tree, pretty_print=True))
def _make_model(n_bodies, n_actuators, random, stiffness_range=(15, 25), damping_range=(0, 0)): """Returns an MJCF XML string defining a model of springs and dampers. Args: n_bodies: An integer, the number of bodies (DoFs) in the system. n_actuators: An integer, the number of actuated bodies. random: A `numpy.random.RandomState` instance. stiffness_range: A tuple containing minimum and maximum stiffness. Each joint's stiffness is sampled uniformly from this interval. damping_range: A tuple containing minimum and maximum damping. Each joint's damping is sampled uniformly from this interval. Returns: An MJCF string describing the linear system. Raises: ValueError: If the number of bodies or actuators is erronous. """ if n_bodies < 1 or n_actuators < 1: raise ValueError('At least 1 body and 1 actuator required.') if n_actuators > n_bodies: raise ValueError('At most 1 actuator per body.') file_path = os.path.join(os.path.dirname(__file__), 'lqr.xml') with resources.GetResourceAsFile(file_path) as xml_file: mjcf = xml_tools.parse(xml_file) parent = mjcf.find('./worldbody') actuator = etree.SubElement(mjcf.getroot(), 'actuator') tendon = etree.SubElement(mjcf.getroot(), 'tendon') for body in range(n_bodies): # Inserting body. child = _make_body(body, stiffness_range, damping_range, random) site_name = 'site_{}'.format(body) child.append(etree.Element('site', name=site_name)) if body == 0: child.set('pos', '.25 0 .1') # Add actuators to the first n_actuators bodies. if body < n_actuators: # Adding actuator. joint_name = 'joint_{}'.format(body) motor_name = 'motor_{}'.format(body) child.find('joint').set('name', joint_name) actuator.append( etree.Element('motor', name=motor_name, joint=joint_name)) # Add a tendon between consecutive bodies (for visualisation purposes only). if body < n_bodies - 1: child_site_name = 'site_{}'.format(body + 1) tendon_name = 'tendon_{}'.format(body) spatial = etree.SubElement(tendon, 'spatial', name=tendon_name) spatial.append(etree.Element('site', site=site_name)) spatial.append(etree.Element('site', site=child_site_name)) parent.append(child) parent = child return etree.tostring(mjcf, pretty_print=True)