flat fitness when loading lua module

[Nathan Timmers]

Hi,

I am quite new to using SCONE and programming in Lua. There is one thing that keeps bugging me.
Whenever I load a module inside my ScriptController the optimizer returns flat fitness. I have tried several things now, even up to the point that the loaded module is empty, but still flat fitness. Only when I remove the require command it does optimize properly

My SCONE file:

Code: Select all

CmaOptimizer {
	signature_prefix = DATE_TIME
	#init_file = data/Gait_10_no_force_20sec.par
	#init_file = data/Gait_10_amp_no_force_30sec.par
	
	SimulationObjective {
		max_duration = 20
		
		# Model used in simulation
		OpenSimModel {
			model_file = data/Human0914.osim
			#fixed_control_step_size = 0.005 # higher step sizes give better performance
			enable_external_forces = 1 # Required when applying external forces
			
			# Optimize initial state parameters
			state_init_file = data/InitStateGait10.sto
			initial_state_offset =	0~0.01<-0.5,0.5>
			initial_state_offset_exclude = "*_tx;*_ty;*_u"
		}
		
		CompositeController {
			# Controller for gait, based on [Geyer & Herr 2010]
			<< data/ControllerGH2010.scone >>
			
			ScriptController {
				name = PerturbationDevice

				script_file = "data/ScriptTest.lua"
			}
			
			
		}
		
		# Measure for gait
		<< data/MeasureGait.scone >>

	}
}

My ScriptTest.lua file:

Code: Select all

function init(model, par)
	legInit = require "Leg"
end

function update(model)
	
	return false
end


function store_data( frame )
	-- store some values for analysis
end

My Leg.lua file (also tried an empty file):

Code: Select all

local Leg = {}
return Leg

What is going on? The require command seems to upset the optimization process. Any tips on how to get it working?

[Thomas Geijtenbeek]

Hi Nathan,

The 'require' command indeed isn't officially supported in SCONE. I suspect the optimizer produces an error because it cannot find the required file, as this isn't copied to the optimization folder. More details should be in the optimization.log file.

I can see how this is hard to derive from the 'flat fitness' message alone. I'll see if I can make a more descriptive error message in a future version of SCONE.

[Nathan Timmers]

Hi Thomas,

Thanks for the fast reply. You're right indeed, it cannot find the "Leg.lua" file. Do you have any suggestions on how to work around this? I was hoping to avoid writing all the code in one script, but that seems necessary if the 'require' command is not supported.

[Nathan Timmers]

I tried adding the absolute path of the 'require' files using a solution found on the internet:

Code: Select all

package.path = package.path ..  ";<... absolute path ....>/data/lua_files/?.lua;"

which solved the issue of flat fitness. However, this approach seems to mess with the optimizer as well, since the model no longer tries to walk but rather falls quicker every iteration.

[Thomas Geijtenbeek]

Hi Nathan,

Using an absolute path is definitely not recommended, since the file is reloaded before each optimization iteration. Changing the file later will cause the optimization to malfunction and the results to be irreproducible.

Unfortunately, using a single script file is the only way to go for now. I have added a feature request to support this in the upcoming version of SCONE; see https://github.com/opensim-org/SCONE/issues/183 for details.

[Thomas Geijtenbeek]

This feature supported in SCONE 1.4.0, simply add the files to external_files in ScriptMeasure / ScriptController:

Code: Select all

external_files = [ required_file_1.lua required_file_2.lua ... ]

[Nathan Timmers]

nice!