Example usage for org.apache.mahout.math Vector getNumNonZeroElements

Introduction

In this page you can find the example usage for org.apache.mahout.math Vector getNumNonZeroElements.

Prototype

int getNumNonZeroElements();

Source Link

Document

Return the number of non zero elements in the vector.

Usage

From source file:com.scaleunlimited.classify.vectors.SetNormalizer.java

License:Apache License

public void normalize(Vector vector) {
    // First count the number of non-zero values.
    double valueCount = vector.getNumNonZeroElements();

    // Set each non-zero value to 1/count of non-zero values, so that
    // it's as if these all have a count of 1, so they have equal TF.
    vector.assign(new DoubleDoubleFunction() {

        @Override//  w  w  w  . j a  v  a 2s. com
        public double apply(double curValue, double normalizedValue) {
            return (curValue > 0.0 ? normalizedValue : 0);
        }

    }, 1.0 / valueCount);
}

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From source file:edu.rosehulman.mahout.math.VectorWritable.java

License:Apache License

public static void writeVector(DataOutput out, Vector vector, boolean laxPrecision) throws IOException {
    boolean dense = vector.isDense();
    boolean sequential = vector.isSequentialAccess();
    boolean named = vector instanceof NamedVector;

    out.writeByte((dense ? FLAG_DENSE : 0) | (sequential ? FLAG_SEQUENTIAL : 0) | (named ? FLAG_NAMED : 0)
            | (laxPrecision ? FLAG_LAX_PRECISION : 0));

    Varint.writeUnsignedVarInt(vector.size(), out);
    if (dense) {//from ww w  . jav a2s .com
        for (Vector.Element element : vector.all()) {
            if (laxPrecision) {
                out.writeFloat((float) element.get());
            } else {
                out.writeDouble(element.get());
            }
        }
    } else {
        Varint.writeUnsignedVarInt(vector.getNumNonZeroElements(), out);
        Iterator<Element> iter = vector.nonZeroes().iterator();
        if (sequential) {
            int lastIndex = 0;
            while (iter.hasNext()) {
                Vector.Element element = iter.next();
                if (element.get() == 0) {
                    continue;
                }
                int thisIndex = element.index();
                // Delta-code indices:
                Varint.writeUnsignedVarInt(thisIndex - lastIndex, out);
                lastIndex = thisIndex;
                if (laxPrecision) {
                    out.writeFloat((float) element.get());
                } else {
                    out.writeDouble(element.get());
                }
            }
        } else {
            while (iter.hasNext()) {
                Vector.Element element = iter.next();
                if (element.get() == 0) {
                    // TODO(robinanil): Fix the damn iterator for the zero element.
                    continue;
                }
                Varint.writeUnsignedVarInt(element.index(), out);
                if (laxPrecision) {
                    out.writeFloat((float) element.get());
                } else {
                    out.writeDouble(element.get());
                }
            }
        }
    }
    if (named) {
        String name = ((NamedVector) vector).getName();
        out.writeUTF(name == null ? "" : name);
    }
}

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