public abstract class Matrix {
	protected final int rows ; // 10 000
	protected final int cols ; // 8
	
	protected Matrix(int rows, int cols) {
		this.rows = rows ;
		this.cols = cols ;
	}
	
	public abstract void set(int i, int j, double d) ;
	public abstract double get(int i, int j) ;
	public void patricia(double[] v, double[] tmp, double[] out) {
		multiplyLeft(v, tmp) ;
		multiplyRight(tmp, out) ;
	}
	public abstract void multiplyLeft(double[] v, double[] out) ;
	public abstract void multiplyRight(double[] v, double[] out) ;
	public final int hashCode() {
		int hash = 0 ;
		for (int i = 0 ; i < rows ; ++i) {
			for (int j = 0 ; j < cols ; ++j) {
				long dBits = Double.doubleToLongBits(get(i, j)) ;
				hash = (hash >> 1) + ((int)dBits) + ((int)(dBits >> 32)) ;
			}
		}
		return hash ;
	}
	public static int hashCode(double[] v) {
		int hash = 0 ;
		for (int i = 0 ; i < v.length ; ++i) {
			long dBits = Double.doubleToLongBits(v[i]) ;
			hash = (hash >> 1) + ((int)dBits) + ((int)(dBits >> 32)) ;
		}
		return hash ;
	}
	public final boolean equals(Object obj) {
		if ((obj == null) || (!(obj instanceof Matrix))) return false ;
		Matrix that = (Matrix)obj ;
		if (this.rows != that.rows) return false ;
		if (this.cols != that.cols) return false ;
		for (int i = 0 ; i < rows ; ++i) {
			for (int j = 0 ; j < cols ; ++j) {
				if (this.get(i, j) != that.get(i, j)) return false ;
			}
		}
		return true ;
	}
	public String toString() {
		return getClass().getName() + " " + rows + " x " + cols ;
	}
}