TITLE:: FluidPCA
summary:: Dimensionality Reduction with Principal Component Analysis
categories:: Dimensionality Reduction, Data Processing
related:: Classes/FluidMDS, Classes/FluidDataSet

DESCRIPTION::

https://scikit-learn.org/stable/modules/decomposition.html#principal-component-analysis-pca

CLASSMETHODS::

METHOD:: new
Make a new instance
ARGUMENT:: server
The server on which to run this model

INSTANCEMETHODS::

PRIVATE:: init

METHOD:: fit
Train this model on a link::Classes/FluidDataSet:: but don't transform the data
ARGUMENT:: dataset
A link::Classes/FluidDataSet:: to analyse
ARGUMENT:: k
The number of dimensions to reduce to
ARGUMENT:: action
Run when done

METHOD:: transform
Given a trained model, apply the reduction to a source link::Classes/FluidDataSet:: and write to a destination. Can be the same
ARGUMENT:: sourceDataset
Source data, or the dataset name
ARGUMENT:: destDataset
Destination data, or the dataset name
ARGUMENT:: action
Run when done

METHOD:: fitTransform
link::Classes/FluidPCA#fit:: and link::Classes/FluidPCA#transform:: in a single pass
ARGUMENT:: sourceDataset
Source data, or the dataset name
ARGUMENT:: destDataset
Destination data, or the dataset name
ARGUMENT:: k
The number of dimensions to reduce to
ARGUMENT:: action
Run when done

METHOD:: transformPoint
Given a trained model, transform the data point in a link::Classes/Buffer:: and write to an output
ARGUMENT:: sourceBuffer
Input data
ARGUMENT:: destBuffer
Output data
ARGUMENT:: action
Run when done

EXAMPLES::

code::

s.boot;
//Preliminaries: we want some audio, a couple of FluidDataSets, some Buffers, a FluidStandardize and a FluidPCA
(
~audiofile = File.realpath(FluidBufPitch.class.filenameSymbol).dirname +/+ "../AudioFiles/Tremblay-ASWINE-ScratchySynth-M.wav";
~raw = FluidDataSet(s,\pca_help_12D);
~reduced = FluidDataSet(s,\pca_help_2D);
~audio = Buffer.read(s,~audiofile);
~mfcc_feature = Buffer.new(s);
~stats = Buffer.new(s);
~datapoint = Buffer.alloc(s,12);
~standardizer  = FluidStandardize(s);
~pca = FluidPCA(s);
)

// Do a mfcc analysis on the audio, which gives us 13 points, and we'll throw the 0th away
// Divide the time series in to 100, and take the mean of each segment and add this as a point to
// the 'raw' FluidDataSet
(
~raw.clear;
~norm.clear;
FluidBufMFCC.process(s,~audio,features:~mfcc_feature,action:{
    "MFCC analysis.complete. Doing stats".postln;
    fork{
        var chunkLen = (~mfcc_feature.numFrames / 100).asInteger;
        100.do{ |i|
            s.sync;    FluidBufStats.process(s,~mfcc_feature,startFrame:i*chunkLen,numFrames:chunkLen,startChan:1, stats:~stats, action:{
            ~stats.loadToFloatArray(action:{ |statsdata|
                    [statsdata[0],statsdata[1]].postln;
                    ~datapoint.setn(0,[statsdata[0],statsdata[1]]);
                    s.sync;
                    ("Adding point" ++ i).postln;
                    ~raw.addPoint(i,~datapoint);
                })
            });
            if(i == 99) {"Analysis done, dataset ready".postln}
        }
    }
});
)

//First standardize our dataset, so that the MFCC dimensions are on comensurate scales
//Then apply the PCA in-place on the standardized data
//Download the dataset contents into an array for plotting
(
~standardizer.fit(~raw);
~standardizer.transform(~raw, ~reduced);
~pca.fitTransform(~raw,~reduced,2);
~reducedarray= Array.new(100);
fork{
    100.do{|i|
        ~reduced.getPoint(i,~datapoint,{

            ~datapoint.loadToFloatArray(action:{|a| ~reducedarray.add(Array.newFrom(a))})
        });
        s.sync;
        if(i==99){"Data downloaded".postln};
    }
}
)


//Visualise the 2D projection of our original 12D data
(
d = ~reducedarray.flatten(1).unlace.deepCollect(1, { |x| x.normalize});
// d = [20.collect{1.0.rand}, 20.collect{1.0.rand}];
w = Window("scatter", Rect(128, 64, 200, 200));
w.drawFunc = {
    Pen.use {
        d[0].size.do{|i|
            var x = (d[0][i]*200);
            var y = (d[1][i]*200);
            var r = Rect(x,y,5,5);
            Pen.fillColor = Color.blue;
            Pen.fillOval(r);
        }
    }
};
w.refresh;
w.front;
)

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