Buyer Seller Force for Amibroker (AFL)

/* Buyer-Seller Force

This indicator illustrates the amount of buying or selling pressure
being exerted on the security.  When in positive territory, the buyers have
the upper hand.  When in negative the sellers rule.

When divergence occurs, the price will tend to correct toward the indicator.

This is specifically written for east coast time NYSE hours.  The code must be
adjusted for any other equities/markets.
*/

day_open_time = (Hour() == 9 AND Minute() == 30);

c_vel = (C - Ref(C, -1)) / Ref(C, -1);
h_vel = (H - Ref(H, -1)) / Ref(H, -1);
l_vel = (L - Ref(L, -1)) / Ref(L, -1);
p_vel = c_vel + h_vel + l_vel;

immediate_pressure = p_vel * V;

numminutes = BarsSince(day_open_time);
day_pressure = Sum(immediate_pressure, numminutes + 1);

Plot(day_pressure, "BSF", colorBlack);