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Reference Guide
TActivationSigmoid.h
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1 // @(#)root/tmva $Id$
2 // Author: Matt Jachowski
3 
4 /**********************************************************************************
5  * Project: TMVA - a Root-integrated toolkit for multivariate data analysis *
6  * Package: TMVA *
7  * Class : TMVA::TActivationSigmoid *
8  * Web : http://tmva.sourceforge.net *
9  * *
10  * Description: *
11  * Sigmoid activation function for TNeuron *
12  * *
13  * Authors (alphabetical): *
14  * Matt Jachowski <jachowski@stanford.edu> - Stanford University, USA *
15  * *
16  * Copyright (c) 2005: *
17  * CERN, Switzerland *
18  * *
19  * Redistribution and use in source and binary forms, with or without *
20  * modification, are permitted according to the terms listed in LICENSE *
21  * (http://tmva.sourceforge.net/LICENSE) *
22  **********************************************************************************/
23 
24 #ifndef ROOT_TMVA_TActivationSigmoid
25 #define ROOT_TMVA_TActivationSigmoid
26 
27 //////////////////////////////////////////////////////////////////////////
28 // //
29 // TActivationSigmoid //
30 // //
31 // Sigmoid activation function for TNeuron //
32 // //
33 //////////////////////////////////////////////////////////////////////////
34 
35 #include "TFormula.h"
36 #include "TString.h"
37 
38 #include "TMVA/TActivation.h"
39 
40 namespace TMVA {
41 
43 
44  public:
45 
48 
49  // evaluate the activation function
50  Double_t Eval(Double_t arg);
51 
52  // evaluate the derivative of the activation function
54 
55  // minimum of the range of the activation function
56  Double_t GetMin() { return 0; }
57 
58  // maximum of the range of the activation function
59  Double_t GetMax() { return 1; }
60 
61  // expression for the activation function
63 
64  // writer of function code
65  virtual void MakeFunction(std::ostream& fout, const TString& fncName);
66 
67  private:
68 
69  TFormula* fEqn; // equation of sigmoid
70  TFormula* fEqnDerivative; // equation of sigmoid derivative
71 
72  ClassDef(TActivationSigmoid,0); // Sigmoid activation function for TNeuron
73  };
74 
75 } // namespace TMVA
76 
77 #endif
Basic string class.
Definition: TString.h:131
Sigmoid activation function for TNeuron.
#define ClassDef(name, id)
Definition: Rtypes.h:320
Double_t EvalDerivative(Double_t arg)
evaluate the derivative of the sigmoid
virtual void MakeFunction(std::ostream &fout, const TString &fncName)
writes the sigmoid activation function source code
TActivationSigmoid()
constructor for sigmoid normalized in [0,1]
The Formula class.
Definition: TFormula.h:83
Double_t Eval(Double_t arg)
evaluate the sigmoid
TString GetExpression()
get expressions for the sigmoid and its derivatives
double Double_t
Definition: RtypesCore.h:55
Abstract ClassifierFactory template that handles arbitrary types.
Interface for TNeuron activation function classes.
Definition: TActivation.h:42