Sigh. VWAP isn't an algorithm, it's a benchmark. Volume-weighted Average Price. An algorithm that is attempting to trade VWAP is trying to get the day's average price, whatever it is. And a good algorithm is quite hard to detect.
http://www.thetradenews.com/algorithmic-trading
VWAP algos try to beat VWAP over the order's timeframe, which is almost never the entire day.