k-fold cross validation in RankLib - machine-learning

I want to do 5 fold cross validation on MQ2008 dataset. I am using RankLib to apply ML algo on the dataset. I am confused about the kcv option given in Ranklib for cross validation.
command used:
java - jar RankLib.jar -ranker 0 -train train.txt -test test.txt -validate vali.txt -kcv 5
here we are specifying different files for training,testing and validation.Then how it is dividing data for 5 fold cross validation.

To do k-fold cross-validation using ranklib, you only need to use one dataset.
The program itself divides the data to train, test and validate randomly.
When you use 5-fold cross-validation, the program will repeat the process 5 times and it gives you the average of the 5 analyses as the final result.
You need to choose a metric for your learning evaluation. See [ -metric2t <metric> ] on this How to use page.
For example, see the command below. I have only one dataset to feed my algorithm. I used NDCG#10 as my evaluation metric. Also, I used -kcvmd to save my models in a directory and -kcvmn to name the models.
java -jar RankLib-2.1-patched.jar -train trainingData.txt -ranker 8 -kcv 5 -kcvmd kcvModels/ -kcvmn txt -metric2t NDCG#10 -metric2T NDCG#10 -save Models/model.txt

Related

Doc2vecC predicting vectors for unseen documents

I have trained a set of documents using Doc2vecc.
https://github.com/mchen24/iclr2017
I am trying to generate the embedding vector for the unseen documents.I have trained the documents as mentioned in the go.sh.
"""
time ./doc2vecc -train ./aclImdb/alldata-shuf.txt -word
wordvectors.txt -output docvectors.txt -cbow 1 -size 100 -window 10 -
negative 5 -hs 0 -sample 0 -threads 4 -binary 0 -iter 20 -min-count 10
-test ./aclImdb/alldata.txt -sentence-sample 0.1 -save-vocab
alldata.vocab
"""
I get the docvectors.txt and wordvectors.txt for the train set. Now from here how do I generate vectors for unseen test using the same model without retraining.
As far as I can tell, the author (https://github.com/mchen24) of that doc2vecc.c code (and paper) just made minimal changes to some example 'paragraph vector' code that was itself a minimal change to the original Google/Mikolov word2vec.c (https://github.com/tmikolov/word2vec/blob/master/word2vec.c).
Neither the 'paragraph vector' changes nor the subsequent doc2vecc changes appear to include any functionality for inferring vectors for new documents.
Because these are unsupervised algorithms, for some purposes it may be appropriate to calculate the document-vectors for some downstream classification task, for both training and test texts, in the same combined bulk training. (Your ultimate goals may in fact have unlabeled examples to help learn the document-vectorization, even if your classifier should be trained an evaluated on some subset of known-label texts.)
Doc2VecC is expressly designed to create document vectors as averages of the word-vectors in each document. This is unlike Doc2Vec where document embeddings are trained alongside the word embeddings making it impossible to handle unseen documents. The amount of trained vectors is also enormous in Doc2Vec.
To build the vector for an unseen document, just count all the words from your vocabulary in it and compute an average of the word-vectors.

How to make a non-static Caffe network architecture?

I would like to implement a neural network architecture in Caffe which will perform differently based on some iterable variable. For example: the full network might use 10 layers for 4 out of 5 training or testing iterations, but for all other iterations it will truncate the network and only use the last 5 layers. This would require that the input to the first layer and the input to the 5th layer have the same dimensionality of course, but my primary question is how to implement this switching between the two architectures during training/testing.
I guess you can do that using pycaffe and caffe.NetSpec(), but this is not going to be a very nice code...
On the other hand, why don't you train for i iterations the full net, save a snapshot, and then "warm start" the reduced model with the snapshot you saved?
That is: have 'full_trainval.prototxt' with 'full_solver.prototxt' configured to train the full net for i iterations, and 'top_trainval.prototxt' with 'top_solver.prototxt' configured to train only the top layers of the net. Then
~$ $CAFFE_ROOT/build/tools/caffe train -solver full_solver.prototxt
When this stage is through, make sure you have the final sanpshot saved, and then
~$ $CAFFE_ROOT/build/tools/caffe train -solver top_solver.prototxt -snapshot full_train_last_snapshot.solverstate
Finally, you could use net_surgery to merge the weights of the two phases into a single full net.

why normalizing feature values doesn't change the training output much?

I have 3113 training examples, over a dense feature vector of size 78. The magnitude of features is different: some around 20, some 200K. For example, here is one of the training examples, in vowpal-wabbit input format.
0.050000 1 '2006-07-10_00:00:00_0.050000| F0:9.670000 F1:0.130000 F2:0.320000 F3:0.570000 F4:9.837000 F5:9.593000 F6:9.238150 F7:9.646667 F8:9.631333 F9:8.338904 F10:9.748000 F11:10.227667 F12:10.253667 F13:9.800000 F14:0.010000 F15:0.030000 F16:-0.270000 F17:10.015000 F18:9.726000 F19:9.367100 F20:9.800000 F21:9.792667 F22:8.457452 F23:9.972000 F24:10.394833 F25:10.412667 F26:9.600000 F27:0.090000 F28:0.230000 F29:0.370000 F30:9.733000 F31:9.413000 F32:9.095150 F33:9.586667 F34:9.466000 F35:8.216658 F36:9.682000 F37:10.048333 F38:10.072000 F39:9.780000 F40:0.020000 F41:-0.060000 F42:-0.560000 F43:9.898000 F44:9.537500 F45:9.213700 F46:9.740000 F47:9.628000 F48:8.327233 F49:9.924000 F50:10.216333 F51:10.226667 F52:127925000.000000 F53:-15198000.000000 F54:-72286000.000000 F55:-196161000.000000 F56:143342800.000000 F57:148948500.000000 F58:118894335.000000 F59:119027666.666667 F60:181170133.333333 F61:89209167.123288 F62:141400600.000000 F63:241658716.666667 F64:199031688.888889 F65:132549.000000 F66:-16597.000000 F67:-77416.000000 F68:-205999.000000 F69:144690.000000 F70:155022.850000 F71:122618.450000 F72:123340.666667 F73:187013.300000 F74:99751.769863 F75:144013.200000 F76:237918.433333 F77:195173.377778
The training result was not good, so I thought I would normalize the features to make them in the same magnitude. I calculated mean and standard deviation for each of the features across all examples, then do newValue = (oldValue - mean) / stddev, so that their new mean and stddev are all 1. For the same example, here is the feature values after normalization:
0.050000 1 '2006-07-10_00:00:00_0.050000| F0:-0.660690 F1:0.226462 F2:0.383638 F3:0.398393 F4:-0.644898 F5:-0.670712 F6:-0.758233 F7:-0.663447 F8:-0.667865 F9:-0.960165 F10:-0.653406 F11:-0.610559 F12:-0.612965 F13:-0.659234 F14:0.027834 F15:0.038049 F16:-0.201668 F17:-0.638971 F18:-0.668556 F19:-0.754856 F20:-0.659535 F21:-0.663001 F22:-0.953793 F23:-0.642736 F24:-0.606725 F25:-0.609946 F26:-0.657141 F27:0.173106 F28:0.310076 F29:0.295814 F30:-0.644357 F31:-0.678860 F32:-0.764422 F33:-0.658869 F34:-0.674367 F35:-0.968679 F36:-0.649145 F37:-0.616868 F38:-0.619564 F39:-0.649498 F40:0.041261 F41:-0.066987 F42:-0.355693 F43:-0.638604 F44:-0.676379 F45:-0.761250 F46:-0.653962 F47:-0.668194 F48:-0.962591 F49:-0.635441 F50:-0.611600 F51:-0.615670 F52:-0.593324 F53:-0.030322 F54:-0.095290 F55:-0.139602 F56:-0.652741 F57:-0.675629 F58:-0.851058 F59:-0.642028 F60:-0.648002 F61:-0.952896 F62:-0.629172 F63:-0.592340 F64:-0.682273 F65:-0.470121 F66:-0.045396 F67:-0.128265 F68:-0.185295 F69:-0.510251 F70:-0.515335 F71:-0.687727 F72:-0.512749 F73:-0.471032 F74:-0.789335 F75:-0.491188 F76:-0.400105 F77:-0.505242
However, this yields basically the same testing result (if not exactly the same, since I shuffle the examples before each training).
Wondering why there is no change in the result?
Here is my training and testing commands:
rm -f cache
cat input.feat | vw -f model --passes 20 --cache_file cache
cat input.feat | vw -i model -t -p predictions --invert_hash readable_model
(Yes, I'm testing on the training data right now since I have only very few data examples to train on.)
More context:
Some of the features are "tier 2" - they were derived by manipulating or doing cross products on "tier 1" features (e.g. moving average, 1-3 order of derivatives, etc). If I normalize the tier 1 features before calculating the tier 2 features, it would actually improve the model significantly.
So I'm puzzled as why normalizing tier 1 features (before generating tier 2 features) helps a lot, while normalizing all features (after generating tier 2 features) doesn't help at all?
BTW, since I'm training a regressor, I'm using SSE as the metrics to judge the quality of the model.
vw normalizes feature values for scale as it goes, by default.
This is part of the online algorithm. It is done gradually during runtime.
In fact it does more than that, vw enhanced SGD algorithm also keeps separate learning rates (per feature) so rarer feature learning rates don't decay as fast as common ones (--adaptive). Finally there's an importance aware update, controlled by a 3rd option (--invariant).
The 3 separate SGD enhancement options (which are all turned on by default) are:
--adaptive
--invariant
--normalized
The last option is the one that adjust values for scale (discounts large values vs small). You may disable all these SGD enhancements by using the option --sgd. You may also partially enable any subset by explicitly specifying it.
All in all you have 2^3 = 8 SGD option combinations you can use.
The Possible reason is that whatever Training algorithm that you used to get the result already did the normalization process for you!.In fact many algorithms do the normalization process before working on it.Hope it helps you :)

Weka Classification

I was trying to data model a Classification Machine Learning algorithm on a data set which has 32 attributes,the last column being Target class.I refined the attributes number in to 6 from 32 ,which I felt would be more useful for my Classification model.
I tried to perform J48 and some incremental classification algorithm.
I expected output structure which consists of confusion matrix,correctlt and incorrectly classified instances,kappa value.
But my result did not give any information on Correctly and Incorrectly classified instances.Also,it did not predict confusion matrix and Kappa value.All I received is like this:
=== Summary ===
Correlation coefficient 0.9482
Mean absolute error 0.2106
Root mean squared error 0.5673
Relative absolute error 13.4077 %
Root relative squared error 31.9157 %
Total Number of Instances 1461
Can anyone tell me why I did not get Confusion matrix,kappa and Correct,Incorrect instances information.
Unfortunately you didnt write your code, or what version of weka do you apply.
BTW, to calculate confusion mtx, kappa etc. you can use methods of Evaluation class, http://weka.sourceforge.net/doc.dev/weka/classifiers/Evaluation.html
for example, after you train your model:
classifier.buildClassifier(train); \\train is an instances
Evaluation eval = new Evaluation(train);
//evaulate your model at 10 fold cross validation manner
eval.crossValidateModel(classifier, train, 10, new Random(1));
System.out.println(classifier);
//print different stats with
System.out.println(eval.toSummaryString());
System.out.println(eval.toMatrixString());
System.out.println(eval.toClassDetailsString());

How to use WEKA Machine Learning for a Bayes Neural Network and J48 Decision Tree

I am trying to figure out WEKA and perform some experiments with data that I have.
Basically what I want to do is take Data Set 1, use it as a training set. Run a J48 Decision Tree on it. Then take Data Set 2 and run the trained tree on it, with the output of the original data set with a extra column for what the prediction was.
Then do the same thing again with the Bayes Neural Network.
Can someone point me to a link of detail instructions on how exactly I would accomplish this? I seem to be missing some steps and cannot get the output of the original data set with the extra column.
Here is one way to do it with the command-line. This information is found in Chapter 1 ("A command-line primer") of the Weka manual that comes with the software.
java weka.classifiers.trees.J48 -t training_data.arff -T test_data.arff -p 1-N
where:
-t <training_data.arff> specifies the training data in ARFF format
-T <test_data.arff> specifies the test data in ARFF format
-p 1-N specifies that you want to output the feature vector and the prediction,
where N is the number of features in your feature vector.
For example, here I am using soybean.arff for both training and testing. There are 35 features in the feature vector:
java weka.classifiers.trees.J48 -t soybean.arff -T soybean.arff -p 1-35
The first few lines of the output look like:
=== Predictions on test data ===
inst# actual predicted error prediction (date,plant-stand,precip,temp,hail,crop-hist,area-damaged,severity,seed-tmt,germination,plant-growth,leaves,leafspots-halo,leafspots-marg,leafspot-size,leaf-shread,leaf-malf,leaf-mild,stem,lodging,stem-cankers,canker-lesion,fruiting-bodies,external-decay,mycelium,int-discolor,sclerotia,fruit-pods,fruit-spots,seed,mold-growth,seed-discolor,seed-size,shriveling,roots)
1 1:diaporth 1:diaporth 0.952 (october,normal,gt-norm,norm,yes,same-lst-yr,low-areas,pot-severe,none,90-100,abnorm,abnorm,absent,dna,dna,absent,absent,absent,abnorm,no,above-sec-nde,brown,present,firm-and-dry,absent,none,absent,norm,dna,norm,absent,absent,norm,absent,norm)
2 1:diaporth 1:diaporth 0.952 (august,normal,gt-norm,norm,yes,same-lst-two-yrs,scattered,severe,fungicide,80-89,abnorm,abnorm,absent,dna,dna,absent,absent,absent,abnorm,yes,above-sec-nde,brown,present,firm-and-dry,absent,none,absent,norm,dna,norm,absent,absent,norm,absent,norm)
The columns are: (1) data instance number; (2) ground truth label; (3) predicted label; (4) error; (5) prediction confidence; and (6) feature vector.

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