John F. Ehlers Predictive Average from his "Rocket Science for Traders" chapter 20 on 2001.

Function:

The concept of taking a difference of lagging line from the original function to produce a leading function suggests extending the concept to moving averages. There is no direct theory for this, but it seems to work pretty well. If taking a 7-bar WMA of prices, that average lags the prices by 2 bars. If taking a 7-bar WMA of the first average, this second average is delayed another 2 bars. If taking the difference between the two averages and add that difference to the first average, the result should be a smoothed line of the original price function with no lag. Sure, Dr. Ehlers tried to use more lag for the second moving average, which
should produce a better predictive curve. However, remember the lesson of Chapter 3 of the book. An analysis curve cannot precede an event. You cannot predict an event before it occurs. If then taking a 4-bar WMA of the smoothed line to create a 1-bar lag, this lagging line becomes a signal when the lines cross. This is as close to an ideal indicator as we can get.

Key Signal

Predict ---> moving average fast line
Trigger ---> moving average slow line

Added a smoothing option if smoothing greater than 1.