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CProductTwoSigmoidalMembershipFunction

Class for implementing the membership function in the form of a product of two sigmoid functions with the А1, А2, С1 and С2 parameters.

Description

A product of two sigmoid membership functions is applied for setting smooth asymmetric functions.  It allows creating membership functions with the values equal to 1 beginning with an argument value. Such functions are suitable if you need to set such linguistic terms as "short" or "long".

fuzzy_prodsigmoidal_function

A sample code for plotting a chart is displayed below.

Declaration

   class CProductTwoSigmoidalMembershipFuncion : public IMembershipFunction

Title

   #include <Math\Fuzzy\membershipfunction.mqh>

Inheritance hierarchy

  CObject

      IMembershipFunction

          CProductTwoSigmoidalMembershipFunctions

Class methods

Class method

Description

A1

Gets and sets the first membership function slope ratio.

A2

Gets and sets the second membership function slope ratio.

C1

Gets the first membership function inflection coordinate parameter.

C2

Gets the second membership function inflection coordinate parameter.

GetValue

Calculates the value of the membership function by a specified argument.

Example

//+------------------------------------------------------------------+
//|                       ProductTwoSigmoidalMembershipFunctions.mq5 |
//|                        Copyright 2016, MetaQuotes Software Corp. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2016, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
#include <Math\Fuzzy\membershipfunction.mqh>
#include <Graphics\Graphic.mqh>
//--- Create membership functions
CProductTwoSigmoidalMembershipFunctions func1(2,1,-1,7);
CProductTwoSigmoidalMembershipFunctions func2(2,2,-4,7);
CProductTwoSigmoidalMembershipFunctions func3(2,3,-8,7);
//--- Create wrappers for membership functions
double ProductTwoSigmoidalMembershipFunctions1(double x) { return(func1.GetValue(x)); }
double ProductTwoSigmoidalMembershipFunctions2(double x) { return(func2.GetValue(x)); }
double ProductTwoSigmoidalMembershipFunctions3(double x) { return(func3.GetValue(x)); }
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//--- create graphic
   CGraphic graphic;
   if(!graphic.Create(0,"ProductTwoSigmoidalMembershipFunctions",0,30,30,780,380))
     {
      graphic.Attach(0,"ProductTwoSigmoidalMembershipFunctions");
     }
   graphic.HistoryNameWidth(70);
   graphic.BackgroundMain("ProductTwoSigmoidalMembershipFunctions");
   graphic.BackgroundMainSize(16);
//--- create curve
   graphic.CurveAdd(ProductTwoSigmoidalMembershipFunctions1,0.0,10.0,0.1,CURVE_LINES,"[2, 1, -1, 7]");
   graphic.CurveAdd(ProductTwoSigmoidalMembershipFunctions2,0.0,10.0,0.1,CURVE_LINES,"[2, 2, -4, 7]");
   graphic.CurveAdd(ProductTwoSigmoidalMembershipFunctions3,0.0,10.0,0.1,CURVE_LINES,"[2, 3, -8, 7]");
//--- sets the X-axis properties
   graphic.XAxis().AutoScale(false);
   graphic.XAxis().Min(0.0);
   graphic.XAxis().Max(10.0);
   graphic.XAxis().DefaultStep(1.0);
//--- sets the Y-axis properties
   graphic.YAxis().AutoScale(false);
   graphic.YAxis().Min(0.0);
   graphic.YAxis().Max(1.1);
   graphic.YAxis().DefaultStep(0.2);
//--- plot
   graphic.CurvePlotAll();
   graphic.Update();
  }


Updated: 2017.03.22