Error when using DCW and DCR

[basvank]

Hi,

I recently tried out the newly added DCW and DCR algorithms but I am getting an error in the ContextSimilarity() function in DCW and ContextRelaxation() function in DCR. The error is java.lang.IndexOutOfBoundsException: Index: 1, Size: 1 and happens in conds1.get(i) in both function classes.

Can you check if you get the same error as well? Or, if not, let me know what settings and data file you use so that I can check if it's a problem on my side?

Thanks for the help!

[irecsys]

I didn't get errors. Can you provide more details? which data were you
using? what's your setting

On Tuesday, June 7, 2016, basvank notifications@github.com wrote:

Hi,

I recently tried out the newly added DCW and DCR algorithms but I am
getting an error in the ContextSimilarity() function in DCW
https://github.com/irecsys/CARSKit/blob/master/src/carskit/alg/cars/transformation/hybridfiltering/DCW.java#L329
and ContextRelaxation() function in DCR
https://github.com/irecsys/CARSKit/blob/master/src/carskit/alg/cars/transformation/hybridfiltering/DCR.java#L343.
The error is java.lang.IndexOutOfBoundsException: Index: 1, Size: 1 and
happens in conds1.get(i) in both function classes.

Can you check if you get the same error as well? Or, if not, let me know
what settings and data file you use so that I can check if it's a problem
on my side?

Thanks for the help!

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[basvank]

Hmm strange, I can indeed get it to work on the InCarMusic dataset. Unfortunately I am working on a dataset consisting of proprietary data so I cannot share that.

The only thing I can think of is the structure of the data set then.

Comparing this (for InCarData):

• Statistics of U-I-C Matrix:
• User amount: 42
• Item amount: 139
• Rate amount: 3938
• Context dimensions: 8 (drivingstyle, landscape, mood, naturalphenomena, roadtype, sleepiness, trafficconditions, weather)
• Context conditions: 35 (drivingstyle: 3, landscape: 5, mood: 6, naturalphenomena: 5, roadtype: 4, sleepiness: 3, trafficconditions: 4, weather: 5)
• Context situations: 28
• Data density: 0.0006%
• Scale distribution: [0.0 x 122, 3.0 x 652, 2.0 x 705, 1.0 x 1452, 4.0 x 513, 5.0 x 494]
• Average value of all ratings: 2.447647
• Standard deviation of all ratings: 1.474440
• Mode of all rating values: 1.000000
• Median of all rating values: 2.000000

To this (my dataset):

• Statistics of U-I-C Matrix:
• User amount: 8385
• Item amount: 51
• Rate amount: 9456
• Context dimensions: 2 (pr, context)
• Context conditions: 13 (pr: 12, context: 1)
• Context situations: 13
• Data density: 0.1668%
• Scale distribution: [1.0 x 9456]
• Average value of all ratings: 1.000000
• Standard deviation of all ratings: 0.000000
• Mode of all rating values: 1.000000
• Median of all rating values: 1.000000

Could it have something to do with the fact that it has only two context dimensions or because dimension context only has one condition? (this is due to the fact that this is context:na, I could try and make it pr:na and see if that works). Do you know if these algorithms work across context dimensions or only across context conditions?

[basvank]

I should note that I have used this dataset succesfully with several other algorithms (CAMF, CSLIM for example) so I don't think the error is due to an incorrect structure.

[basvank]

Ah, changing the context from context:na to pr:na seems to solve it. The statistics then become as follows:

• Statistics of U-I-C Matrix:
• User amount: 8385
• Item amount: 51
• Rate amount: 9456
• Context dimensions: 1 (pr)
• Context conditions: 13 (pr: 13)
• Context situations: 13
• Data density: 0.1540%
• Scale distribution: [1.0 x 9456]
• Average value of all ratings: 1.000000
• Standard deviation of all ratings: 0.000000
• Mode of all rating values: 1.000000
• Median of all rating values: 1.000000

So it seems the algorithm can't handle a single context condition within a dimension.

I'm letting it run now to be sure it completes successfully.

[basvank]

Next error now, java.lang.IllegalArgumentException: fromIndex(0) > toIndex(-1) in predict() because I have num.neighbors=-1.

I have changed this line to k = (k > knn && knn > 0) ? knn : k; which solves this particular error and it's running again now...

[basvank]

All working just fine now!