Source code for test_Integrators

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# Copyright (c) 2023, Autonomous Vehicle Systems Lab, University of Colorado at Boulder
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#
# Basilisk Unit Test
#
# Purpose:  Unit test of the dynamics integrator function
# Author:   Hanspeter Schaub
# Creation Date:  Dec. 14, 2016
#

import inspect
import os

import matplotlib.pyplot as plt
import numpy as np
import pytest
# import simulation related support
from Basilisk.simulation import spacecraft
from Basilisk.simulation import svIntegrators
# import general simulation support files
from Basilisk.utilities import SimulationBaseClass
from Basilisk.utilities import macros
from Basilisk.utilities import orbitalMotion
from Basilisk.utilities import simIncludeGravBody
from Basilisk.utilities import unitTestSupport  # general support file with common unit test functions

# @cond DOXYGEN_IGNORE
filename = inspect.getframeinfo(inspect.currentframe()).filename
path = os.path.dirname(os.path.abspath(filename))


# @endcond

# uncomment this line is this test is to be skipped in the global unit test run, adjust message as needed
# @pytest.mark.skipif(conditionstring)
# uncomment this line if this test has an expected failure, adjust message as needed
# @pytest.mark.xfail(True, reason="Scott's brain no-worky\n")
# The following 'parametrize' function decorator provides the parameters and expected results for each
#   of the multiple test runs for this test.
[docs] @pytest.mark.parametrize("integratorCase", ["rk4", "rkf45", "rkf78", "euler", "rk2", "rk3", "bogackiShampine"]) def test_scenarioIntegrators(show_plots, integratorCase): """This function is called by the py.test environment.""" # each test method requires a single assert method to be called [testResults, testMessage] = run(True, show_plots, integratorCase) assert testResults < 1, testMessage
[docs] def run(doUnitTests, show_plots, integratorCase): """Call this routine directly to run the tutorial scenario.""" testFailCount = 0 # zero unit test result counter testMessages = [] # create empty array to store test log messages # Create simulation variable names simTaskName = "simTask" simProcessName = "simProcess" # Create a sim module as an empty container scSim = SimulationBaseClass.SimBaseClass() # # create the simulation process # dynProcess = scSim.CreateNewProcess(simProcessName) # create the dynamics task and specify the integration update time simulationTimeStep = macros.sec2nano(120.) dynProcess.addTask(scSim.CreateNewTask(simTaskName, simulationTimeStep)) # # setup the simulation tasks/objects # # initialize spacecraft object and set properties scObject = spacecraft.Spacecraft() scObject.ModelTag = "spacecraftBody" # default case, RK4 is automatically setup, no extra code is needed if integratorCase == "rkf45": integratorObject = svIntegrators.svIntegratorRKF45(scObject) integratorObject.setRelativeTolerance(0) integratorObject.setAbsoluteTolerance(0.01) scObject.setIntegrator(integratorObject) if integratorCase == "rkf78": integratorObject = svIntegrators.svIntegratorRKF78(scObject) integratorObject.setRelativeTolerance(0) integratorObject.setAbsoluteTolerance(0.01) scObject.setIntegrator(integratorObject) elif integratorCase == "euler": integratorObject = svIntegrators.svIntegratorEuler(scObject) scObject.setIntegrator(integratorObject) elif integratorCase == "rk2": integratorObject = svIntegrators.svIntegratorRK2(scObject) scObject.setIntegrator(integratorObject) elif integratorCase == "rk3": integratorObject = svIntegrators.svIntegratorRungeKutta( scObject, a_coefficients=[ [0, 0, 0], [0.5, 0, 0], [-1, 2, 0] ], b_coefficients=[1/6, 2/3, 1/6], c_coefficients=[0, 0.5, 1] ) scObject.setIntegrator(integratorObject) elif integratorCase == "bogackiShampine": integratorObject = svIntegrators.svIntegratorAdaptiveRungeKutta( scObject, largest_order=3, a_coefficients=[ [0, 0, 0, 0], [1/2, 0, 0, 0], [0 , 3/4, 0, 0], [2/9, 1/3, 4/9, 0] ], b_coefficients=[7/24, 1/4, 1/3, 1/8], b_star_coefficients=[2/9, 1/3, 4/9, 0], c_coefficients=[0, 1/2, 3/4, 1] ) integratorObject.setRelativeTolerance(0) integratorObject.setAbsoluteTolerance(0.0001) scObject.setIntegrator(integratorObject) # add spacecraft object to the simulation process scSim.AddModelToTask(simTaskName, scObject) # clear prior gravitational body and SPICE setup definitions gravFactory = simIncludeGravBody.gravBodyFactory() earth = gravFactory.createEarth() earth.isCentralBody = True # ensure this is the central gravitational body mu = earth.mu # attach gravity model to spacecraft scObject.gravField.gravBodies = spacecraft.GravBodyVector(list(gravFactory.gravBodies.values())) # # setup orbit and simulation time # # setup the orbit using classical orbit elements oe = orbitalMotion.ClassicElements() rLEO = 7000. * 1000 # meters oe.a = rLEO oe.e = 0.0001 oe.i = 33.3 * macros.D2R oe.Omega = 48.2 * macros.D2R oe.omega = 347.8 * macros.D2R oe.f = 85.3 * macros.D2R rN, vN = orbitalMotion.elem2rv(mu, oe) oe = orbitalMotion.rv2elem(mu, rN, vN) # # initialize Spacecraft States with in the initialization variables # scObject.hub.r_CN_NInit = rN # m - r_CN_N scObject.hub.v_CN_NInit = vN # m - v_CN_N # set the simulation time n = np.sqrt(mu / oe.a / oe.a / oe.a) P = 2. * np.pi / n simulationTime = macros.sec2nano(0.75 * P) # # Setup data logging before the simulation is initialized # numDataPoints = 100 samplingTime = unitTestSupport.samplingTime(simulationTime, simulationTimeStep, numDataPoints) dataLog = scObject.scStateOutMsg.recorder(samplingTime) scSim.AddModelToTask(simTaskName, dataLog) # # initialize Simulation # scSim.InitializeSimulation() # # configure a simulation stop time and execute the simulation run # scSim.ConfigureStopTime(simulationTime) scSim.ExecuteSimulation() # # retrieve the logged data # posData = dataLog.r_BN_N velData = dataLog.v_BN_N # # plot the results # np.set_printoptions(precision=16) fileNameString = filename[len(path) + 6:-3] if integratorCase == "rk4": plt.close("all") # clears out plots from earlier test runs # draw orbit in perifocal frame b = oe.a * np.sqrt(1 - oe.e * oe.e) p = oe.a * (1 - oe.e * oe.e) plt.figure(1, figsize=np.array((1.0, b / oe.a)) * 4.75, dpi=100) plt.axis(np.array([-oe.rApoap, oe.rPeriap, -b, b]) / 1000 * 1.25) # draw the planet fig = plt.gcf() ax = fig.gca() planetColor = '#008800' planetRadius = earth.radEquator / 1000 ax.add_artist(plt.Circle((0, 0), planetRadius, color=planetColor)) # draw the actual orbit rData = [] fData = [] labelStrings = ("rk4", "rkf45", "rkf78", "euler", "rk2") for idx in range(0, len(posData)): oeData = orbitalMotion.rv2elem(mu, posData[idx], velData[idx]) rData.append(oeData.rmag) fData.append(oeData.f + oeData.omega - oe.omega) plt.plot(rData * np.cos(fData) / 1000, rData * np.sin(fData) / 1000 # , color=unitTestSupport.getLineColor(labelStrings.index(integratorCase) + 1, len(labelStrings)) , label=integratorCase , linewidth=3.0 ) # draw the full osculating orbit from the initial conditions fData = np.linspace(0, 2 * np.pi, 100) rData = [] for idx in range(0, len(fData)): rData.append(p / (1 + oe.e * np.cos(fData[idx]))) plt.plot(rData * np.cos(fData) / 1000, rData * np.sin(fData) / 1000 , '--' , color='#555555' ) plt.xlabel('$i_e$ Cord. [km]') plt.ylabel('$i_p$ Cord. [km]') plt.legend(loc='lower right') plt.grid() if doUnitTests: # only save off the figure if doing a unit test run # unitTestSupport.saveScenarioFigure( # fileNameString # , plt, path) # unitTestSupport.saveFigurePDF( # fileNameString # , plt, path # ) unitTestSupport.writeFigureLaTeX( "scenarioIntegrators", "Illustration of the BSK integrated trajectories", plt, "", path) if show_plots: plt.show() plt.close('all') # # close the plots being saved off to avoid over-writing old and new figures # plt.close("all") # # the python code below is for the unit testing mode. If you are studying the scenario # to learn how to run BSK, you can stop reading below this line. # if doUnitTests: numTruthPoints = 5 skipValue = int(len(posData) / (numTruthPoints - 1)) dataPosRed = posData[::skipValue] # setup truth data for unit test if integratorCase == "rk4": truePos = [ [-2.8168016010234915e6, 5.248174846916147e6, 3.677157264677297e6] , [-6.379381726549218e6, -1.4688565370540658e6, 2.4807857675497606e6] , [-2.230094305694789e6, -6.410420020364709e6, -1.7146277675541767e6] , [4.614900659014343e6, -3.60224207689023e6, -3.837022825958977e6] , [5.879095186201691e6, 3.561495655367985e6, -1.3195821703218794e6] ] if integratorCase in {"rkf45", "rkf78", "bogackiShampine"}: truePos = [[ 5879286.370258273, 3561242.50810664, -1319786.625981673]] dataPosRed = dataPosRed[-1,:][np.newaxis] if integratorCase == "euler": truePos = [ [-2.8168016010234915e6, 5.248174846916147e6, 3.677157264677297e6] , [-7.061548530211288e6, -1.4488790844105487e6, 2.823580168201031e6] , [-4.831279689590867e6, -8.015202650472983e6, -1.1434851461593418e6] , [719606.5825106134, -1.0537603309084207e7, -4.966060248346598e6] , [6.431097055190775e6, -9.795566286964862e6, -7.438012269629238e6] ] if integratorCase == "rk2": truePos = [ [-2.8168016010234915e6, 5.248174846916147e6, 3.677157264677297e6] , [-6.425636528569288e6, -1.466693214251768e6, 2.50438327358707e6] , [-2.466642497083674e6, -6.509473992136429e6, -1.6421621818735446e6] , [4.342561337924192e6, -4.1593822658140697e6, -3.947594705237753e6] , [6.279757158711852e6, 2.8527385905952943e6, -1.8260959147806289e6] ] if integratorCase == "rk3": truePos = [ [-2816801.601023492 , 5248174.846916147 , 3677157.2646772973], [-6380014.419169294 , -1467304.5024778044, 2481775.1156921615], [-2231193.424069216 , -6407257.277104054 , -1712704.800575082 ], [ 4613563.820461048 , -3590442.718508557 , -3831202.081509318 ], [ 5853794.060191272 , 3579538.889746918 , -1299292.6887013493] ] # compare the results to the truth values accuracy = 1.0 # meters testFailCount, testMessages = unitTestSupport.compareArray( truePos, dataPosRed, accuracy, "r_BN_N Vector", testFailCount, testMessages) # print out success message if no error were found if testFailCount == 0: print("PASSED ") passFailText = "PASSED" colorText = 'ForestGreen' # color to write auto-documented "PASSED" message in in LATEX snippetContent = "" else: print(testFailCount) print(testMessages) passFailText = 'FAILED' colorText = 'Red' # color to write auto-documented "FAILED" message in in LATEX snippetContent = r"\begin{verbatim}" for message in testMessages: snippetContent += message snippetContent += r"\end{verbatim}" snippetMsgName = fileNameString + 'Msg-' + integratorCase unitTestSupport.writeTeXSnippet(snippetMsgName, snippetContent, path) snippetPassFailName = fileNameString + 'TestMsg-' + integratorCase snippetContent = r'\textcolor{' + colorText + '}{' + passFailText + '}' unitTestSupport.writeTeXSnippet(snippetPassFailName, snippetContent, path) # each test method requires a single assert method to be called # this check below just makes sure no sub-test failures were found return [testFailCount, ''.join(testMessages)]
# # This statement below ensures that the unit test scrip can be run as a # stand-along python script # if __name__ == "__main__": run(True, # do unit tests True, # show_plots 'bogackiShampine') # integrator case(0 - RK4, 1 - RKF45, 2 - Euler, 3 - RK2, 4 - RK3)