g++ [flags ...] file ... -l /isip/tools/lib/$ISIP_BINARY/lib_numeric.a

#include <Sigmoid.h>

boolean set(float gain, float slope, float xoffset, float yoffset);
boolean compute(float& y, float x);

Sigmoid sigm(1, 0.5);
float y;
float x = 0.5;

// evaluate y = sigmoid(x)
//
sigm.compute(y, x);

// evaluate y = derivative with respect to 'x' of the sigmoid function
// evaluated at x
//
sigm.derivative(y, x);

                     gain
  y(x) = -------------------------------  + y_offset
         1 + e^(-slope * (x - x_offset))
  

• This example shows how to create and evaluate a sigmoid function:

  #include <Sigmoid.h>
  #include <VectorDouble.h>
  
  int main() {
  
    // declare a Sigmoid object
    //
    Sigmoid sigm;
  
    // set the parameters of the sigmoid:
    // gain = 0.5, slope = 0.2, xoffset = 1, yoffset = 0
    //
    sigm.set(0.5, 0.2, 1, 0);
  
    // declare the input and output vectors
    //
    VectorDouble input(L"0, 1, -1, 2, -2");
    VectorDouble output;
  
    // compute the sigmoid function at the prescribed input points
    //
    sigm.compute(output, input);
  
    // exit gracefully
    //
    Integral::exit();
  }

• This class has internal data (parameter settings for the Sigmoid) and must be instantiated before being used.