I'm new to answer set programming and could use some help. I've been reading this, but still could use some help. How would I use answer set programming to tell if a graph is strongly connected?
My brainstorming:
Graph represented by nodes and edges (ie; node(1..2), edge(1,2), and edge(2,1)).
Now I need rule "strong() :- ......" that is true if the graph is strongly connected.
A graph is strongly connected if you can start at any node and reach any other node by following the edges in the direction(s) they point.
So my program needs to take each node X and go along the directed edges to try and reach every other node. True if it reaches every other node, False otherwise.
Strong() :- ?
First, unless your graph is directed, you have to get the symmetric edges:
edge(X,Y):- edge(Y,X).
Then, you need to tell that two nodes are connected if there is a path between them:
connected(X,Y):- edge(X,Y).
connected(X,Z):- edge(X,Y) ; connected(Y,Z).
Now, strong holds if for all pairs of nodes, they are connected:
strong:- connected(X,Y): edge(X,_), edge(_,Y).
An alternative version could be:
not_strong:- not connected(X,Y) ; edge(X,_) ; edge(_,Y).
strong:- not not_strong.
(Tested with clingo 4.5.4)
Related
I'm trying to filter a signal and then analyse the values of the filtered signal using Tone.js / Web-Audio API.
I'm expecting to get values of the filtered signal, but I only get -Infinity, meaning that my connections between the nodes are wrong. I've made a small fiddle demonstrating this, however in my use-case I do not want to send this node to the destination of the context - I only want to analyse it, not hear it.
osc.connect(filter)
filter.connect(gainNode)
gainNode.connect(meter)
console.log(meter.getLevel())
I guess you tested the code in Chrome because there is a problem with Chrome which causes it to not process anything until it is connected to the destination. When using Tone.js that means you need to call .toMaster() at the end of your chain. I updated you fiddle to make it work: https://jsfiddle.net/8f7abzoL/.
In Firefox calling .toMaster() is not necessary therefore the following works in Firefox as well: https://jsfiddle.net/yrjgfdtz/.
After some digging I've found out that I need to have a scriptProcessorNode - which is apparently no longer recommended - so looking into Audio Worklet Nodes
I've been given a task to set up an openai toy gym which can only be solved by an agent with memory. I've been given an example with two doors, and at time t = 0 I'm shown either 1 or -1. At t = 1 I can move to correct door and open it.
Does anyone know how I would go about starting out? I want to show that a2c or ppo can solve this using an lstm policy. How do I go about setting up environment, etc?
To create a new environment in gym format, it should have the 5 functions mentioned in the gym.core file.
https://github.com/openai/gym/blob/e689f93a425d97489e590bba0a7d4518de0dcc03/gym/core.py#L11-L35
To lay this down in steps-
Define observation space and action space for your environment, preferably using gym.spaces module.
Write down the step function which performs agent's action and returns a 4 tuple containing - next set of observations from the environment , reward ,
done - a boolean indicating whether the episode is over , and some extra info if you want.
Write a reset function for the environment to reinitialise the episode to a random start state and return a 4 tuple similar to step.
These functions are enough to be able to run an RL agent on your environment.
You can skip the render, seed and close functions if you want.
For the task you have defined,you can model the observation and action space using Discrete(2). 0 for first door and 1 for second door.
Reset would return in it's observation which door has the reward.
Then agent would choose either of the door - 0 or 1.
Then perform a environment step by calling step(action), which will return agent's reward and done flag as true - signifying that the episode is over.
Frankly, the problem you describe seems too simple to accomplish for any reinforcement learning algorithm, but I assume you have provided that as an example.
Remembering for longer horizons is usually harder.
You can read their documentation and toy environments to understand how to create one.
I currently am using Max/MSP to create an interactive system between lights and sound.
I am using Philips hue lighting which I have hooked up to Max/MSP and now I am wanting to trigger an increase in brightness/saturation on the input of a note from a Midi instrument. Does anyone have any ideas how this might be accomplished?
I have built this.
I used the shell object. And then feed an array of parameters into it via a javascipt file with the HUE API. There is a lag time of 1/6 of a second between commands.
Javascript file:
inlets=1;
outlets=1;
var bridge="192.168.0.100";
var hash="newdeveloper";
var bulb= 1;
var brt= 200;
var satn= 250;
var hcolor= 10000;
var bulb=1;
function list(bulb,hcolor,brt,satn,tran) {
execute('PUT','http://'+bridge+'/api/'+hash+'/lights/'+bulb+'/state', '"{\\\"on\\\":true,\\\"hue\\\":'+hcolor+', \\\"bri\\\":'+brt+',\\\"sat\\\":'+satn+',\\\"transitiontime\\\":'+tran+'}"');
}
function execute($method,$url,$message){
outlet(0,"curl --request",$method,"--data",$message,$url);
}
To control Philips Hue you need to issue calls to a restful http based api, like so: http://www.developers.meethue.com/documentation/core-concepts, using the [jweb] or [maxweb] objects: https://cycling74.com/forums/topic/making-rest-call-from-max-6-and-saving-the-return/
Generally however, to control lights you use DMX, the standard protocol for professional lighting control. Here is a somewhat lengthy post on the topic: https://cycling74.com/forums/topic/controlling-video-and-lighting-with-max/, scroll down to my post from APRIL 11, 2014 | 3:42 AM.
To change the bri/sat of your lights is explained in the following link (Registration/Login required)
http://www.developers.meethue.com/documentation/lights-api#16_set_light_state
You will need to know the IP Address of your hue hue bridge which is explained here: http://www.developers.meethue.com/documentation/getting-started and a valid username.
Also bear in mind the performance limitations. As a general rule you can send up to 10 lightstate commands per second. I would recommend having a 100ms gap between each one, to prevent flooding the bridge (and losing commands).
Are you interested in finding out details of who to map this data from a MIDI input to the phillips HUE lights within max? or are you already familiar with Max.
Using Tommy b's javascript (which you could put into a js object), You could for example scale the MIDI messages you want to use using midiin and borax objects and map them to the outputs you want using the scale object. Karlheinz Essl's RTC library is a good place to start with algorithmic composition if you want to transform the data at all http://www.essl.at/software.html
+1 for DMX light control via Max. There are lots of good max-to-dmx tutorials and USB-DMX hardware is getting pretty cheap. However, as someone who previously believed in dragging a bunch of computer equipment on stage just to control a light or two with an instrument, I'd recommend researching and purchasing a simple one channel "color organ" circuit kit (e.g., Velleman MK 110). Controlling a 120/240V light bulb via audio is easier than you might think; a computer for this type of application is usually overkill. Keep it simple and good luck!
I'm working with the web audio API. Say I have a source buffer node. Is there any way that I could connect it to 2 different delay nodes? Like
var sourceNode = context.createBufferSource();
sourceNode.buffer = myBuffer;
sourceNode.connect(delayNode1);
sourceNode.connect(delayNode2);
? The way I have it here does not work. It only connects to delayNode2.
Yes, of course. I'm not sure why you're not finding that code to work; it absolutely should (and similar code works for me). If you have it running in place somewhere I can take a look.
I've started using V-Rep to simulate some robots (Pioneers and quadrotors, initially), but I've been having problems when I try to connect it with ROS. I tried to replicate the example from RosTopicPublisherAndSubscriber.ttt and it only works the first time, after I close it and load it again, it doesn't work anymore, my code is practically identical to the example, except that I use getPose and it's a Pioneer (the one that comes with V-Rep), here's my code:
if (simGetScriptExecutionCount()==0) then
-- Check if the required plugin is there (libv_repExtRos.so or libv_repExtRos.dylib):
local moduleName=0
local moduleVersion=0
local index=0
local pluginNotFound=true
while moduleName do
moduleName,moduleVersion=simGetModuleName(index)
if (moduleName=='Ros') then
pluginNotFound=false
end
index=index+1
end
if (pluginNotFound) then
simDisplayDialog('Error','ROS plugin was not found.&&nSimulation will not run properly',sim_dlgstyle_ok,false,nil,{0.8,0,0,0,0,0},{0.5,0,0,1,1,1})
else
-- Retrive the handle of the vision sensor we wish to stream:
lHandle=simGetObjectHandle('Pioneer_p3dx')
-- Now enable topic publishing and streaming of the vision sensor's data:
topicName=simExtROS_enablePublisher('p3dx',1,simros_strmcmd_get_object_pose,lHandle,0,'')
if (topicName == nil) then
simDisplayDialog('Error','Nil',sim_dlgstyle_ok,false,nil,{0.8,0,0,0,0,0},{0.5,0,0,1,1,1})
else
simDisplayDialog('Error','Not Nil',sim_dlgstyle_ok,false,nil,{0.8,0,0,0,0,0},{0.5,0,0,1,1,1})
end
-- Retrive the handle of the passive vision sensor. We will use the passive vision sensor
end
end
Any idea is welcome! Thanks in advance!
PS: Also, if anyone with 1500 reputation points could create the v-rep tag, that would be great!
Ok, the people at V-REP helped me solve it. So basically I should used the argument as -1 instead of 0.
So basically, a should have done this
topicName=simExtROS_enablePublisher('p3dx',1,simros_strmcmd_get_object_pose,lHandle,-1,'')
instead of
topicName=simExtROS_enablePublisher('p3dx',1,simros_strmcmd_get_object_pose,lHandle,0,'')