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Python-DP-Means-Clustering
==========================

Comparing DP-means and K-means clustering algorithms

"cluster.py" has implementations of k-means and dp-means clustering algorithms.
Implementations were intended to be straight-forward, understandable and give
full output for diagnostics, rather than optimized implmentations.

For more information on the dp-means, see Revisiting k-means: New Algorithms 
via Bayesian Nonparametrics at http://arxiv.org/abs/1111.0352/

CLUSTERING
==========

> ./cluster.py -h
Usage: cluster.py [options]

Options:
  -h, --help            show this help message and exit
  -k CLUSTERS, --kmeans-clusters=CLUSTERS
                        If present, use kmeans with number of clusters
                        specified
  -l LAM, --lamda=LAM   If preset, use dpmeans with lambda parameters
                        specified
  -x XVAL, --cross-validate=XVAL
                        Number of records to hold out for cross validations.
                        Data will be random-ordered for you.
  -s, --cross-validate-stop
                        Stop when cross-validation error rises.

> cat input/c3_s20_f2.csv | ./cluster.py -k2
Tolerance reached at step 8
Iterations completed: 8
Final error: 2.994711
elapsed time: 6.582022 ms

> cat input/c3_s20_f2.csv | ./cluster.py -k2
Tolerance reached at step 3
Iterations completed: 3
Final error: 2.994711
elapsed time: 2.923965 ms

> cat input/c3_s20_f2.csv | ./cluster.py -l2
Tolerance reached at step 4
Iterations completed: 4
Final error: 0.520926
elapsed time: 5.388021 ms

> cat input/c3_s20_f2.csv | ./cluster.py -l5
Tolerance reached at step 2
Iterations completed: 2
Final error: 2.994711
elapsed time: 2.490044 ms

To plot errors for the last run (dp-means in this case), use "plotResult.r"
This script reads ./output/results.csv and ./output/error.csv.

> ./plotResult.r 
Loading required package: methods
Loading required package: grid
       V1               V2                 V3                 V4     cluster
 Min.   :-4.997   Min.   :-4.11117   Min.   :0.000   Iter-0    :65   0:103  
 1st Qu.:-3.413   1st Qu.:-3.01148   1st Qu.:0.000   Iter-1    :65   1: 90  
 Median :-2.562   Median :-2.34123   Median :2.000   Iter-2    :65   2: 59  
 Mean   :-1.606   Mean   :-1.68030   Mean   :1.918   Iter-3    :65   3: 12  
 3rd Qu.: 1.425   3rd Qu.:-0.01388   3rd Qu.:4.000   Iter-4    :65   4:126  
 Max.   : 2.224   Max.   : 2.00472   Max.   :4.000   Iter-Final:65          
       V1          V2        
 Min.   :0   Min.   :0.5209  
 1st Qu.:1   1st Qu.:0.5209  
 Median :2   Median :0.5388  
 Mean   :2   Mean   :0.6489  
 3rd Qu.:3   3rd Qu.:0.5777  
 Max.   :4   Max.   :1.0860  

See training output images created in ./img/iters.png and ./img/error.png

OPTIMAL DP-MEANS
================
Finds the optimal value of lambda only from data.

cat input/c4_s300_f2.csv | ./DPopt.py

...
Final error: 18.510049
Final cross-validation error: 18.223702
Tolerance reached at step 6
Iterations completed: 6
Final error: 14.329098
Final cross-validation error: 14.262425
lambda: 5.48775
  with error: 14.26242

Code holds back 20% of data for training optimization.

There are no parameters to set unless you anticipate more than the default max
number of clusters (set in code).

CREATE TEST DATA
================
> ./createTestData.py -h
Usage: createTestData.py [options]

Options:
  -h, --help            show this help message and exit
  -s SAMPLE, --sample-size=SAMPLE
                        Sample size per cluster
  -f FEATURES, --features=FEATURES
                        Number of features
  -c CLUSTERS, --clusters=CLUSTERS
                        Sample size
  -o OVERLAP, --overlap=OVERLAP
                        0 - distinct, 1 - scale = sig

> ./createTestData.py -s6 -c1 -f3
2.80484810546906,-5.107337369680055,1.7687444192348534
4.045291632153071,-4.955840347993885,1.5936351799326172
3.503220395140305,-5.008280722637208,1.5695863487866264
3.2134872837791812,-4.809839458886229,1.3158740999089755
3.8383496901618197,-4.745260338782687,1.74511375801971
3.3736868708580805,-5.2559718245077045,1.4113521104252063

CLUSTERING TESTS
================

Example test run on data set with 3 features, 100 points per cluster, with 4 clusters.

> ./test.py | tee output/test.all.csv | grep -v Inter > output/test.csv
...
Tolerance reached at step 1
Iterations completed: 1
Final error: 0.091798
Tolerance reached at step 1
Iterations completed: 1
Final error: 0.091798
Tolerance reached at step 1
Iterations completed: 1
Final error: 0.091798
Tolerance reached at step 1
Iterations completed: 1
Final error: 0.091798
Tolerance reached at step 1
Iterations completed: 1
Final error: 0.091798
Tolerance reached at step 1
Iterations completed: 1
Final error: 0.091798
...

> ./test.py -h
Usage: test.py [options]

Options:
  -h, --help            show this help message and exit
  -f FILE, --file=FILE  Input file name
  -i ITER, --iterations=ITER
                        Iterations to use in searching for min error. Default
                        20.


Plot the test results,

> ./plotTest.r 
Loading required package: methods
Loading required package: grid
        V1           V2                V3               V4         
 dp-means:12   Min.   : 0.5774   Min.   : 1.046   Min.   :  345.6  
 k-means :12   1st Qu.: 2.7424   1st Qu.: 2.722   1st Qu.: 1438.7  
               Median : 4.8094   Median : 3.758   Median : 4243.7  
               Mean   : 5.1264   Mean   : 7.159   Mean   : 4779.7  
               3rd Qu.: 6.9462   3rd Qu.: 6.242   3rd Qu.: 5946.4  
               Max.   :12.0000   Max.   :33.695   Max.   :12496.4  
      method  
 dp-means:12  
 k-means :12  

See ./img/test_errors.png and ./img/test_times.png for comparative error and times
for k-means and dp-means.

NOTE: lambda is chosen based on relevant scale of the data. In this example, the data set
was created to fall between -5 and 5, so the range is 10.  The maximum lambda is there 10, 
while the smallest lambda could be chosen as the smallest expected cluster size.  

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DP-means K-means clustering algorithms comparison

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