Simplify trend and optimism.

[stockfish] / src / misc.h

diff --git a/src/misc.h b/src/misc.h
index fe1143def0b35150eeedf51d3976baa46beb467e..77b81d50fc00e02465413273e398a083f41de6c8 100644 (file)
--- a/src/misc.h
+++ b/src/misc.h
@@ -126,33 +126,6 @@ private:
 };
 
 
-/// sigmoid(t, x0, y0, C, P, Q) implements a sigmoid-like function using only integers,
-/// with the following properties:
-///
-///  -  sigmoid is centered in (x0, y0)
-///  -  sigmoid has amplitude [-P/Q , P/Q] instead of [-1 , +1]
-///  -  limit is (y0 - P/Q) when t tends to -infinity
-///  -  limit is (y0 + P/Q) when t tends to +infinity
-///  -  the slope can be adjusted using C > 0, smaller C giving a steeper sigmoid
-///  -  the slope of the sigmoid when t = x0 is P/(Q*C)
-///  -  sigmoid is increasing with t when P > 0 and Q > 0
-///  -  to get a decreasing sigmoid, change sign of P
-///  -  mean value of the sigmoid is y0
-///
-/// Use <https://www.desmos.com/calculator/jhh83sqq92> to draw the sigmoid
-
-inline int64_t sigmoid(int64_t t, int64_t x0,
-                                  int64_t y0,
-                                  int64_t  C,
-                                  int64_t  P,
-                                  int64_t  Q)
-{
-   assert(C > 0);
-   assert(Q != 0);
-   return y0 + P * (t-x0) / (Q * (std::abs(t-x0) + C)) ;
-}
-
-
 /// xorshift64star Pseudo-Random Number Generator
 /// This class is based on original code written and dedicated
 /// to the public domain by Sebastiano Vigna (2014).