Method pNormDist

JSAT/src/jsat/linear/Vec.java:736–794

Returns the p-norm distance between this and another vector y. @param p the distance type. 2 is the common value @param y the other vector to compare against @return the p-norm distance

(double p, Vec y)

     * @return the p-norm distance
     */
    public double pNormDist(double p, Vec y)
    {
        Iterator<IndexValue> thisIter = this.iterator();
        Iterator<IndexValue> otherIter = y.iterator();
        if (!thisIter.hasNext())
            if (!otherIter.hasNext())
                return 0;
            else
                return y.pNorm(p);
        else if (!otherIter.hasNext())
            return this.pNorm(p);

        double result = 0;
        
        IndexValue av = thisIter.next();
        IndexValue bv = otherIter.next();
        
        do
        {
            boolean nextA = false, nextB = false;
            if (av.getIndex() == bv.getIndex())
            {
                result += pow(abs(av.getValue() - bv.getValue()), p);
                nextA = nextB = true;
            }
            else if(av.getIndex() < bv.getIndex())
            {
                result += pow(abs(av.getValue()), p);
                nextA = true;
            }
            else if(av.getIndex() > bv.getIndex())
            {
                result += pow(abs(bv.getValue()), p);
                nextB = true;
            }
            
            if(nextA)
                av = thisIter.hasNext() ? thisIter.next() : null;
            if(nextB)
                bv = otherIter.hasNext() ? otherIter.next() : null;
        }
        while (av != null && bv != null);
        
        //accumulate left overs
        while(av != null)
        {
            result += pow(abs(av.getValue()), p);
            av = thisIter.hasNext() ? thisIter.next() : null;
        }
        
        while(bv != null)
        {
            result += pow(abs(bv.getValue()), p);
            bv = otherIter.hasNext() ? otherIter.next() : null;
        }
            
        
        return pow(result, 1/p);