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| = Exercise Sheet 1 = [[attachment:SearchEnginesWS0910/ExerciseSheet1/lecture-1.pdf|Here is a PDF of the slides of Lecture 1]]. |
Here are PDFs of the slides of the lectures so far: [[attachment:SearchEnginesWS0910/lecture-1.pdf|Lecture 1]], [[attachment:SearchEnginesWS0910/lecture-2.pdf|Lecture 2]], [[attachment:SearchEnginesWS0910/lecture-3.pdf|Lecture 3]], [[attachment:SearchEnginesWS0910/lecture-4.pdf|Lecture 4]], [[attachment:SearchEnginesWS0910/lecture-5.pdf|Lecture 5]]. |
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| [[attachment:SearchEnginesWS0910/ExerciseSheet1/exercise-1.pdf|Here is a PDF of Exercise Sheet 1]]. | Here are .lpd files of the recordings of the lectures so far (except Lecture 2, where we had problems with the microphone): [[http://vulcano.informatik.uni-freiburg.de/lecturnity/lecture-1.lpd|Recording Lecture 1]], [[http://vulcano.informatik.uni-freiburg.de/lecturnity/lecture-3.lpd|Recording Lecture 3]], [[http://vulcano.informatik.uni-freiburg.de/lecturnity/lecture-4.lpd|Recording Lecture 4]], [[http://vulcano.informatik.uni-freiburg.de/lecturnity/lecture-5.lpd|Recording Lecture 5 (no audio)]]. |
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| [[SearchEnginesWS0910/StudentIntros|Introduce yourself on this page please (Exercise 1)]]. | Here are PDFs of the exercise sheets so far: [[attachment:SearchEnginesWS0910/exercise-1.pdf|Exercise Sheet 1]], [[attachment:SearchEnginesWS0910/exercise-2.pdf|Exercise Sheet 2]], [[attachment:SearchEnginesWS0910/exercise-3.pdf|Exercise Sheet 3]], [[attachment:SearchEnginesWS0910/exercise-4.pdf|Exercise Sheet 4]], [[attachment:SearchEnginesWS0910/exercise-5.pdf|Exercise Sheet 5]]. |
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| [[SearchEnginesWS0910/ExerciseSheet1|Upload your results to Exercise Sheet 1 on this page please]]. | Here are your solutions and comments on the previous exercise sheets: [[SearchEnginesWS0910/ExerciseSheet1|Solutions and Comments 1]], [[SearchEnginesWS0910/ExerciseSheet2|Solutions and Comments 2]], [[SearchEnginesWS0910/ExerciseSheet3|Solutions and Comments 3]], [[SearchEnginesWS0910/ExerciseSheet4|Solutions and Comments 4]]. = Exercise Sheet 5 = The recordings of all lectures are now available, see above. Lecture 2 is missing because we had technical problems there. To play the recordings (it's .lpd files) you need the Lecturnity Player. [[http://www.lecturnity.de/de/download/lecturnity-player|You can download the player for free here]]. [[SearchEnginesWS0910/Rules|Here are the rules for the exercises as explained in Lecture 2]]. [[SearchEnginesWS0910/ExerciseSheet5|Here you can upload your solutions for Exercise Sheet 5]]. |
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| Hi Björn + all: occurrence always means individual occurrence, that is, if a collection has two documents and the word x occurs once in the first document and twice in the second document then there are three occurrences of this word overall. Ok? '''Hannah 25Oct09 2:12pm''' | For the exp/bin-search intersection algorithm it clearly matters that it searches for the elements of the smaller list in the larger one. A good implementation will certainly take care of that. Should our implementation also do that or ignore it in order to get 16 measurements that are really different? '''Björn 22Nov09 1:00pm''' |
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| To Zhongjie + all: you are right, you can't add the #acl line to the document yourself, so I just did it for you. I will change the instructions on the upload page accordingly. Sorry for this initial confusion, but hey, good that we have a Wiki. '''Hannah 25Oct09 2:06pm''' | |
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| Hey everyone! Whenever the exercise is talking about frequencies and occurences. Does it talk about occurences in different documents or should we considre multiple occurences in the same document. Thanks a lot. '''Björn''' | Ok, no problem, I'm happy when it's clear now. '''Hannah 22Nov09 0:24am''' |
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| To Johannes: How did you solve the problem? I have logged in my account as my name, and my email links only this account. But I still get the error message 'You can't change ACLs on this page since you have no admin rights on it! ' when I try to enter '#acl ZhongjieCai:read,write -All:read ' to the first line of the page... '''Zhongjie 25Oct09 01:15am''' | You're right, I misread your comment, sorry. I was thinking of 10MB per lists processed in 1 second, resulting in 20MB/s and was wondering where the 100MB/s are coming from. '''Thomas 22Nov09 00:20am''' |
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| Problem solved. To everybody: don't try to create multiple users with the same e-mail address. '''Johannes 25Oct09 00:21am''' | Hi Thomas, I am at a loss of words here. I am saying a car is driving 20 kilometers and it needs 10 minutes for that, so its average speed was 120 km / hours. And you are saying how can the speed of a car be 120 km / hours, when it only drives 20 kilometers. Well, what should I say. Besides, in my example I clearly said that the two lists ''together'' occupy 10 MB, not 10 MB per list. Please read again what I wrote. '''Hannah 22Nov09 0:16am''' |
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| Oh, I see, well that *must* be your user name. Sorry for not making that clear earlier. Please create an account with that user name and try again. '''Hannah 25Oct09 00:02am''' | Why should two lists of 10MB size result in 100MB processed, if each list is only iterated over once to do the intersection (O(m+n) complexity)? The data processed after all is just 20MB, no matter how the algorithm is implemented (even if it iterates a thousand times over every list, it still just processed 20MB of data). '''Thomas 21Nov09 12:00am''' |
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| No that is not my user name. '''Johannes 24Oct09 11:58pm''' | By the way, whenever I talk about "lists" here or on the exercise sheets or in the lecture, I am not referring to a particular data structure (in particular I am NOT talking about a linked list), but "list of elements" is just "series of elements". And well, "inverted list" is just common terminology. To implement a "list of doc ids" or anything like that you should of course always use an array or a vector or a data structure like that. '''Hannah 21Nov09 8:30pm''' |
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| Hi Johannes, if you are logged in as JohannesStork you should be able to see it, did you try that? '''Hannah 24Oct09 11:59pm'''I don't know if this is the right place to ask, but I can't access my exercise page. It says "Sie dürfen diese Seite nicht ansehen." '''Johannes 24Oct09 11:50pm''' | Hi Marius + all, let me explain it by an example. Your two input lists occupy a certain amount of memory. Every programming language has built-in functions for this. For example, if your list entries are ints, then for C++ you can use sizeof(int) to get the number of bytes occupied by one entry. Multiply by the number of list elements to get the number of bytes occupied by one list. One Megabyte (MB) is 1024 * 1024 bytes. Now assume your two lists together occupy 10 MB. Assume your code takes 0.1 seconds to intersect these two lists. Then the "MB processed per second" is 100 MB / second. '''Hannah 21Nov09 8:26pm''' |
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| Good question, Johannes. Please upload the source code separately, either as a .zip or .tgz archive. I have modified the instructions on the upload page accordingly. Sorry if that means additional work for you, we weren't expecting anybody to submit so early ... '''Hannah 24Oct09 11:43pm''' | Hi, in exercise 3, what do you mean by "MB processed per second"? Is a MB the equivalent to 4096 processed integers? And when is a MB to be considered as processed? When it's written to the intersected list or in the comparisons, already? '''Marius 21Nov09 7:33pm''' |
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| Shall we put the whole source into the PDF? What about tar.gz? '''Johannes 24Oct09 5:18pm''' | The slides + all my hand-writing on it are now online, see the link ''Recording Lecture 5 (no audio)'' above. '''Hannah 20Nov09 3:24am''' |
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| Hi Johannes + all, the slides are now availabe as PDF, see the link above. '''Hannah 23Oct09 17:04''' | The recording of todays lecture again did not work. I am very sorry for that (and very angry that there are so many problems with this software). Anyway, the end result of the lecture, that is the slides with all the writing on it are available and I will put them online as soon as possible. '''Hannah 19Nov09 11:23pm''' |
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| '''Note about Exercise 5:''' One can assume that a more general model of the word frequencies is given than that given in the lecture, i.e. eps * N * (1 / i^alpha). Now both parameters (eps and alpha) can be estimated simultaneously. '''Marjan 23Oct09 3:29pm''' Can you provide the slides as PDF? '''Johannes 23Oct09 10:05am''' Please note that the deadline for uploading your solutions of the exercises is always Monday, 23:59 (sharp). '''Marjan 22Oct09 6:15pm''' When you add a question or comment here, please end it with your name and the date and time in bold face, just like I did now. '''Hannah 22Oct09 01:59am''' |
There is a typo in Exercise 5 of the new sheet. The two occurrences of ''n'' should be ''m''. '''Hannah 19Nov09 11:22pm''' |
Welcome to the Wiki page of the course Search Engines, WS 2009 / 2010. Lecturer: Hannah Bast. Tutorials: Marjan Celikik. Course web page: click here.
Here are PDFs of the slides of the lectures so far: Lecture 1, Lecture 2, Lecture 3, Lecture 4, Lecture 5.
Here are .lpd files of the recordings of the lectures so far (except Lecture 2, where we had problems with the microphone): Recording Lecture 1, Recording Lecture 3, Recording Lecture 4, Recording Lecture 5 (no audio).
Here are PDFs of the exercise sheets so far: Exercise Sheet 1, Exercise Sheet 2, Exercise Sheet 3, Exercise Sheet 4, Exercise Sheet 5.
Here are your solutions and comments on the previous exercise sheets: Solutions and Comments 1, Solutions and Comments 2, Solutions and Comments 3, Solutions and Comments 4.
Exercise Sheet 5
The recordings of all lectures are now available, see above. Lecture 2 is missing because we had technical problems there. To play the recordings (it's .lpd files) you need the Lecturnity Player. You can download the player for free here.
Here are the rules for the exercises as explained in Lecture 2.
Here you can upload your solutions for Exercise Sheet 5.
Questions or comments below this line, most recent on top please
For the exp/bin-search intersection algorithm it clearly matters that it searches for the elements of the smaller list in the larger one. A good implementation will certainly take care of that. Should our implementation also do that or ignore it in order to get 16 measurements that are really different? Björn 22Nov09 1:00pm
Ok, no problem, I'm happy when it's clear now. Hannah 22Nov09 0:24am
You're right, I misread your comment, sorry. I was thinking of 10MB per lists processed in 1 second, resulting in 20MB/s and was wondering where the 100MB/s are coming from. Thomas 22Nov09 00:20am
Hi Thomas, I am at a loss of words here. I am saying a car is driving 20 kilometers and it needs 10 minutes for that, so its average speed was 120 km / hours. And you are saying how can the speed of a car be 120 km / hours, when it only drives 20 kilometers. Well, what should I say. Besides, in my example I clearly said that the two lists together occupy 10 MB, not 10 MB per list. Please read again what I wrote. Hannah 22Nov09 0:16am
Why should two lists of 10MB size result in 100MB processed, if each list is only iterated over once to do the intersection (O(m+n) complexity)? The data processed after all is just 20MB, no matter how the algorithm is implemented (even if it iterates a thousand times over every list, it still just processed 20MB of data). Thomas 21Nov09 12:00am
By the way, whenever I talk about "lists" here or on the exercise sheets or in the lecture, I am not referring to a particular data structure (in particular I am NOT talking about a linked list), but "list of elements" is just "series of elements". And well, "inverted list" is just common terminology. To implement a "list of doc ids" or anything like that you should of course always use an array or a vector or a data structure like that. Hannah 21Nov09 8:30pm
Hi Marius + all, let me explain it by an example. Your two input lists occupy a certain amount of memory. Every programming language has built-in functions for this. For example, if your list entries are ints, then for C++ you can use sizeof(int) to get the number of bytes occupied by one entry. Multiply by the number of list elements to get the number of bytes occupied by one list. One Megabyte (MB) is 1024 * 1024 bytes. Now assume your two lists together occupy 10 MB. Assume your code takes 0.1 seconds to intersect these two lists. Then the "MB processed per second" is 100 MB / second. Hannah 21Nov09 8:26pm
Hi, in exercise 3, what do you mean by "MB processed per second"? Is a MB the equivalent to 4096 processed integers? And when is a MB to be considered as processed? When it's written to the intersected list or in the comparisons, already? Marius 21Nov09 7:33pm
The slides + all my hand-writing on it are now online, see the link Recording Lecture 5 (no audio) above. Hannah 20Nov09 3:24am
The recording of todays lecture again did not work. I am very sorry for that (and very angry that there are so many problems with this software). Anyway, the end result of the lecture, that is the slides with all the writing on it are available and I will put them online as soon as possible. Hannah 19Nov09 11:23pm
There is a typo in Exercise 5 of the new sheet. The two occurrences of n should be m. Hannah 19Nov09 11:22pm