I'm currently working on an answer set program to create a timetable for a school.
The rule base I use looks similar to this:
teacher(a). teacher(b). teacher(c). teacher(d). teacher(e). teacher(f).teacher(g).teacher(h).teacher(i).teacher(j).teacher(k).teacher().teacher(m).teacher(n).teacher(o).teacher(p).teacher(q).teacher(r).teache(s).teacher(t).teacher(u).
teaches(a,info). teaches(a,math). teaches(b,bio). teaches(b,nawi). teaches(c,ge). teaches(c,gewi). teaches(d,ge). teaches(d,grw). teaches(e,de). teaches(e,mu). teaches(f,de). teaches(f,ku). teaches(g,geo). teaches(g,eth). teaches(h,reli). teaches(h,spo). teaches(i,reli). teaches(i,ku). teaches(j,math). teaces(j,chem). teaches(k,math). teaches(k,chem). teaches(l,deu). teaches(l,grw). teaches(m,eng). teaches(m,mu). teachs(n,math). teaches(n,geo). teaches(o,spo). teaches(o,fremd). teaches(p,eng). teaches(p,fremd). teaches(q,deu). teaches(q,fremd). teaches(r,deu). teaches(r,eng). teaches(s,eng). teaches(s,spo). teaches(t,te). teaches(t,eng). teaches(u,bio). teaches(u,phy).
subject(X) :- teaches(_,X).
class(5,a). class(5,b). class(6,a). class(6,b). class(7,a). class(7,b). class(8,a). class(8,b). class(9,a). class(9,b). class(10,a). class(10,b).
%classes per week (for class 5 only at the moment)
classperweek(5,de,5). classperweek(5,info,0). classperweek(5,eng,5). classpereek(5,fremd,0). classperweek(5,math,4). classperweek(5,bio,2). classperweek(5,chem,0). classperweek(5,phy,0). classperweek(5,ge,1). classperweek(5,grw,0). cassperweek(5,geo,2). classperweek(5,spo,3). classperweek(5,eth,2). classperwek(5,ku,2). classperweek(5,mu,2). classperweek(5,tec,0). classperweek(5,nawi,0) .classperweek(5,gewi,0). classperweek(5,reli,2).
room(1..21).
%for monday to friday
weekday(1..5).
%for lesson 1 to 9
slot(1..9).
In order to creat a timetable I wanted to create every possible combination of all predicats I'm using and then filter all wrong answers.
This is how I created a timetable:
{timetable(W,S,T,A,B,J,R):class(A,B),teacher(T),subject(J),room(R)} :- weekday(W), slot(S).
Up to this point everything works, except that this solution is probably relatively inefficient.
To filter that no class uses the same room at the same time I formulated the following constraint.
:- timetable(A,B,C,D,E,F,G), timetable(H,I,J,K,L,M,N), A=H, B=I, G=N, class(D,E)!=class(K,L).
It looks like this makes to problem so big that the grounding fails, because I get the following error message
clingo version 5.4.0
Reading from timetable.asp
Killed
Therefore, I was looking for a way to create different instances of timetable without getting too many "meaningless" answers created by the choiserule.
One possibility I thought of is to use a negation cycle. So you could replace the choiserule
{a;b} with a :- not b. b :- not a. and exclude all cases where rooms are occupied twice.
Unfortunately I do not understand this kind of approach enough to apply it to my problem.
After a lot of trial and error (and online search), I have not found a solution to eliminate the choicerule and at the same time eliminate the duplication of rooms and teachers at the same time.
Therefore I wonder if I can use this approach for my problem or if there is another way to not create many pointless answersets at all.
edit: rule base will work now and updated the hours per lesson for class 5
I think you're looking for something like:
% For each teacher and each timeslot, pick at most one subject which they'll teach and a class and room for them.
{timetable(W,S,T,A,B,J,R):class(A,B),room(R),teaches(T,J)} <= 1 :- weekday(W);slot(S);teacher(T).
% Cardinality constraint enforcing that no room is occupied more than once in the same timeslot on the timetable.
:- #count{uses(T,A,B,J):timetable(W,S,T,A,B,J,R)} > 1; weekday(W); slot(S); room(R).
to replace your two rules.
Note that this way clingo won't generate spurious ground terms for teachers teaching a subject they don't know. Additionally by using a cardinality constraint as opposed to a binary clause, you get a big-O reduction in the grounded size (from O(n^2) in the number of rooms to O(n)).
Btw, you may be missing answers because of typos in the input. I would suggest phrasing it as:
teacher(a;b;c;d;e;f;g;h;i;j;k;l;m;n;o;p;q;r;s;t;u).
teaches(
a,info;
a,math;
b,bio;
b,nawi;
c,ge;
c,gewi;
d,ge;
d,grw;
e,de;
e,mu;
f,de;
f,ku;
g,geo;
g,eth;
h,reli;
h,spo;
i,reli;
i,ku;
j,math;
j,chem;
k,math;
k,chem;
l,deu;
l,grw;
m,eng;
m,mu;
n,math;
n,geo;
o,spo;
o,fremd;
p,eng;
p,fremd;
q,deu;
q,fremd;
r,deu;
r,eng;
s,eng;
s,spo;
t,te;
t,eng;
u,bio;
u,phy
).
subject(X) :- teaches(_,X).
class(
5..10,a;
5..10,b
).
%classes per week (for class 5 only at the moment)
classperweek(
5,de,5;
5,info,0;
5,eng,5;
5,fremd,0;
5,math,4;
5,bio,2;
5,chem,0;
5,phy,0;
5,ge,1;
5,grw,0;
5,geo,2;
5,spo,3;
5,eth,2;
5,ku,2;
5,mu,2;
5,tec,0;
5,nawi,0;
5,gewi,0;
5,reli,2
).
room(1..21).
%for monday to friday
weekday(1..5).
%for lesson 1 to 9
slot(1..9).
I'm quite new to ELK and Grok-filtering, and I'm struggling with parsing this particular pattern in my grok filter.
I've used the grok debugger to try and solve this, but although I like the tool, I just get confused by the custom patterns.
Eventually, I hope to parse lots of log files sent by filebeat to logstash, then send the parsed logs to elasticsearch and display with kibana or some similar visualization tool.
The lines that I need to parse follow the following pattern:
1310 2017-01-01 16:48:54 [325:51] [326:49] [359:57] Some log info text
The first four digits is a log type identifier, and will be used for grouping. I've called the field "LogLineID".
The date is formatted YYYY-MM-DD HH:MM:SS, and is parsed ok. I called the field "LogDate".
But now the problem begins. Within the square brackets, I have counters, formatted as MM:SS if you like. I cannot for the life of me find a way to sort these out, but I need to compare these times, hence I want to store them as minutes and seconds, not just numbers.
The first is a counter "TimeSpent",
the second is a counter "TimeStarted" and
the third is a counter "TimeSinceDown".
Then, last, comes the info text, which I've managed to grok with simply applying %{GREEDYDATA:LogInfo}.
I notice that the amount of minutes could be far higher than the standard 60 minutes within an hour, so I may be barking up the wrong tree here trying to parse it with date patterns such as TIMESTAMP_ISO8601, but then, I don't really know how else to do this.
So, I came this far:
%{NUMBER:LogLineID} %{TIMESTAMP_ISO8601:LogDate}
and were as mentioned able to (by cutting away the square bracket parts) to parse the log info text with
%{GREEDYDATA:LogInfo}
to create a field LogInfo.
But that's were I'm stuck. Could someone please help me figure out the rest?
Massive thanks in advance.
PS! I also found %{NUMBER:duration}, but it could as far as I could tell only parse timestamps with dot, not colon..
grok regex expression can help you solve the problem.
but first I wanna make sure that do you mean [325:51] [326:49] [359:57] are the three component that you wanna to fetch? And it will returns the result like :
TimeSpent: 325:51
TimeStarted: 326:49
TimeSinceDown: 359:57
were i get the point , you can use my ways in on of the following suggestions:
define your own custom pattern files and add the pattern in your file.
just use the expression in filter part of logstash conf file
hope it will helps you
Ah, there was a space.. Actually, I was misleading myself and everybody in my question, as it was not actually that log line that was causing problems. I just took the first one, not realizing where the problem really were, but the one causing problems had a space within the brackets as such: [ 42:31]. There are also some parts where there are two spaces, so the way I managed to solve this was to include a %{SPACE} between the \[ and the %{NUMBER}:
%{NUMBER:LogLineID} %{TIMESTAMP_ISO8601:LogDate} \[%{SPACE}%{NUMBER:TimeSpentMinutes}\:%{NUMBER:TimeSpentSeconds}\] \[%{SPACE}%{NUMBER:TimeStartedMinutes}\:%{NUMBER:TimeStartedSeconds}\] \[%{SPACE}%{NUMBER:TimeSinceDownMinutes}\:%{NUMBER:TimeSinceDownSeconds}\] %{GREEDYDATA:LogText}
I still haven't solved the merging of minutes and seconds, but this I can also handle in a later stage.
Thanks to Lin Don for showing an interest in my problem, and sorry for not replying sooner.
Hope the solution will help others (or even myself) if their stuck on the same kind of problem.
Note to myself: Read the logs more carefully before grok'ing.. :)
So I wanted to try my hand out creating a decision table from a rule that I've already made in a .drl file. Then I wanted to convert it back to a .drl. Didn't see any nifty conversions from drl to xls/csv nor was the jboss documentation comprehensive enough. It could be the rule is too complicated for a simple decision table but I was hoping this community could help me out.
Here is the drl:
rule "Patient: Compute BMI"
when
$basic : BasicInfoModel(
notPresent('bmi'),
isPresent('height'),
isPresent('weight'),
$height : value('height', 0.0),
$weight : value('weight', 0.0))
then
modify($basic){
put('bmi', $weight / Math.pow($height,2))
};
end
So this rule basically looks at an objects weight and height field and then computes the bmi. I've tried basically taking what I have and putting it into the decision table format but with little success. Nothing really parses (I'm just using the droolsSpreadSheet.compile and printing out what I get, which is a whole of empty rules). Any help would be appreciated!
Update:
This is what my excel sheet looks like
This is what my rule parses out to:
package DROOLS;
//generated from Decision Table
import basic.BasicInfoModel;
// rule values at A11, header at A6
rule "Computing BMI"
when
$patient:BasicInfoModel(notPresent('bmi'), isPresent('height'),isPresent('weight'), $height:value('height', 0.0), $weight:value('weight',0.0) == "20,4")
then
end
Update #2: I think I figured out my parse issues. Here is my new and improved spreadsheet., Basically found out that I cannot have the Computing BMI: data blank, there must be something in there in order to have the rule parse (Which isn't entirely clear in the docs I read, though that could be because my experience with decision tables is novice putting it lightly).
So now the compile looks more like what I want:
// rule values at A11, header at A6
rule "Computing BMI"
when
$patient:BasicInfoModel(notPresent('bmi'), isPresent('height'), isPresent('weight') == "TRUE")
$weight:value('weight',0.0), $height:value('height', 0.0)
then
modify($patient){put('bmi', $weight / Math.pow($height,2))};
end
Can someone confirm that I have to have real, specific data in the rules in order for them to parse? Can I just use injection elsewhere? Perhaps I should ask a new question on this.
So the answer is yes, you do need parameters, but what I didn't know was that the data doesn't have to be hardcoded like every example I've come across. Thanks to stumbling onto this answer. So now the table looks like this. I hope this helps others who've come across this issue. Also my recommendation is to just make your drools in a .drl rather than go through the spreadsheet, unless you have a bunch of rules that are pretty much copy and paste replicas. That's my two cents anyways.
I am using MSXML v3.0 in a VB 6.0 application. The application calculates sum of an attribute of all nodes using for each loop as shown below
Set subNodes = docXML.selectNodes("//Transaction")
For Each subNode In subNodes
total = total + Val(subNode.selectSingleNode("Amount").nodeTypedValue)
Next
This loop is taking too much time, sometime it takes 15-20 minutes for 60 thousand nodes.
I am looking for XPath/DOM solution to eliminate this loop, probably
docXML.selectNodes("//Transaction").Sum("Amount")
or
docXML.selectNodes("Sum(//Transaction/Amount)")
Any suggestion is welcomed to get this sum faster.
// Open the XML.
docNav = new XPathDocument(#"c:\books.xml");
// Create a navigator to query with XPath.
nav = docNav.CreateNavigator();
// Find the sum
// This expression uses standard XPath syntax.
strExpression = "sum(/bookstore/book/price)";
// Use the Evaluate method to return the evaluated expression.
Console.WriteLine("The price sum of the books are {0}", nav.Evaluate(strExpression));
source: http://support.microsoft.com/kb/308333
Any solution that uses the XPath // pseudo-operator on an XML document with 60000+ nodes is going to be quite slow, because //x causes a complete traversal of the tree starting at the root of the document.
The solution can be speeded up significantly, if a more exact XPath expression is used, that doesn't include the // pseudo-operator.
If you know the structure of the XML document, always use a specific chain of location steps -- never //.
If you provide a small example, showing the specific structure of the document, then many people will be able to provide a faster solution than any solution that uses //.
For example, if it is known that all Transaction elements can be selected using this XPath expression:
/x/y/Transaction
then the evaluation of
sum(/x/y/Transaction/Amount)
is likely to be significantly faster than Sum(//Transaction/Amount)
Update:
The OP has revealed in a comment that the structure of the XML file is quite simple.
Accordingly, I tried with a 60000 Transaction nodes XML document the following:
/*/*/Amount
With .NET XslCompiledTransform (Yes, I used XSLT as the host for the XPath engine) this took 220ms (milliseconds), that means 0.22 seconds, to produce the sum.
With MSXML3 it takes 334 seconds.
With MSXML6 it takes 76 seconds -- still quite slow.
Conclusion: This is a bug in MSXML3 -- try to upgrade to another XPath engine, such as the one offered by .NET.