public double getMaxValueFromColumn(int y) throws UnknownColumnException {	
		if(y >= 0 && y < this.countColumns) {
	        double maxValue = getValue(0, y);
	        for(int x = 1; x < this.countLines; x++) {
	            if(getValue(x,y) > maxValue)
	            	maxValue = getValue(x,y);
	        }
	        return maxValue;
	    }
	    else
	        throw new UnknownColumnException(y);
	}