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Hello,

I would like to be able to run multiple simulations in a row without having to press the play/stop buttons in the Editor. I would like to run a Python program, have it start a simulation, continue until a certain condition is reached, stop the simulation, reset everything (the whole scene) to initial conditions with possibly a few modifications and repeat all that n times.

I have tried following the suggestion posted in this topic by Marc Liévin and using the PyMechanismViewer.py program as a reference, but I do not know how to proceed further. So far I only have a code that starts the simulation. How can I break out of the loop and reset everything? 

From my understanding this cannot be accomplished using key frames if I want to modify some parameters or content from one simulation to the next.

Thanks in advance.

Lyon Belyansky

Hi Lyon,

I see two ways to implement what you are looking for

1.

- have a python script implementing the following

a. instantiate an application

b. load content, ideally a scene

c. apply a set of parameters, e.g. using VHL

d. run simulation and save outputs

- have another script calling the previous one and passing a set of parameters so that several runs are performed

2.

- have a python script implementing the following

a. instantiate an application

b. load content, ideally a scene

c. save keyframe0

d. apply a set of parameters, e.g. using VHL

e. run simulation and save outputs

f. apply keyframe0, go back to d

1. is guarantee to work but is slower

2. is using keyframe and emulates what the Editor is actually doing

Marc.

If you are interested in using the python moudle 'unittest', we also have an example of tests using it together with some helpers, have a look in \Vortex Studio Content 2020a\Demo Scenes\Verification\.

the helpers provide a decorator that allows parametrization of the test function using @VxATPUtils.parametrized

from vxatp import *
from VxSim import *
import matplotlib.pyplot as plt
# In case of an import error, a re-installation of the matplotlib module may solve the issue. Please run the following command with administrator priviledges:
# pip install --upgrade --force-reinstall matplotlib
import os.path
import unittest

class VehicleValidation(unittest.TestCase):
    directory = os.path.dirname(os.path.realpath(__file__))

    def test_lav_speed(self):
        """ Create an application, load the sample scene and retrieve the vehicle's controls needed for the simulation """
        application = VxATPConfig.createApplication(self, setup=VxATPConfig.getAppConfigWithGraphics())
        vehicle_scene = application.getSimulationFileManager().loadObject('%s/../Scenario/Defense Vehicles Scene/'
                                                                          'Defense vehicles.vxscene' % self.directory)
        lav = vehicle_scene.findExtensionByName('LAV').toObject()
        self.assertIsNotNone(lav, "** LAV not found **")
        control_script = lav.findExtensionByName('LAV Driver Interface')
        self.assertIsNotNone(control_script, "** LAV driver interface not found **")

        # Find the controls from the driver interface
        gear_up = control_script.getInput('Gear Up')
        throttle = control_script.getInput('Throttle')
        brake = control_script.getInput('Brake')
        speed = control_script.getOutput('Speed')
        current_gear = control_script.getOutput('Current Gear')
        application.update()

        """ Gather speed values at various gears during simulation and append them to a list """
        lav_speed_list = list()

        # Engage transmission's first gear and set engine to full throttle
        gear_up.value = True
        throttle.value = 1
        application.update()

        # Allow the vehicle to reach maximum speed in 1st gear
        for x in range(90):
            application.update()
            lav_speed_list.append(speed.value)

        # Shift to second, then 3rd gear. Interrupt 'Gear up' signal between each action
        gear_up.value = False
        application.update()
        gear_up.value = True
        application.update()
        gear_up.value = False
        application.update()
        gear_up.value = True
        # Let vehicle go forward for 250 steps.
        for x in range(250):
            application.update()
            lav_speed_list.append(speed.value)
        # Vehicle should be in 3rd gear
        self.assertEqual(current_gear.value, 'D3', "** LAV has not engaged third gear **")
        # Vehicle's speed should reach at least 18 km/hr
        self.assertGreaterEqual(speed.value, 18, "** LAV has not reach expected speed **")

        # Cut throttle, apply full brake
        throttle.value = 0
        brake.value = 1
        # Wait for the vehicle to stop completely
        while speed.value > 0:
            application.update()
            lav_speed_list.append(speed.value)

        # Create a graphical representation of the simulation data
        plt.plot(lav_speed_list)
        plt.grid(True)
        plt.title('LAV- 1st, 2nd and 3rd gear, full throttle')
        plt.xlabel('Simulation step')
        plt.ylabel('Speed (km/h)')
        plt.savefig('%s/LAV speed scenario 1.jpg' % self._config.output_directory)
        print "Test completed successfully. Please check the content of the \Tests results\ folder"


if __name__ == '__main__':
    vxatp_run_thisfile('.\Tests results')