-- Created on: 1991-07-25
-- Created by: Laurent PAINNOT
-- Copyright (c) 1991-1999 Matra Datavision
-- Copyright (c) 1999-2014 OPEN CASCADE SAS
--
-- This file is part of Open CASCADE Technology software library.
--
-- This library is free software; you can redistribute it and/or modify it under
-- the terms of the GNU Lesser General Public License version 2.1 as published
-- by the Free Software Foundation, with special exception defined in the file
-- OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
-- distribution for complete text of the license and disclaimer of any warranty.
--
-- Alternatively, this file may be used under the terms of Open CASCADE
-- commercial license or contractual agreement.

generic class Gradient from AppParCurves
    	    	    (MultiLine   as any;
    	    	     ToolLine    as any)   -- as ToolLine(MultiLine)


    ---Purpose: This algorithm uses the algorithms LeastSquare, 
    --          ResConstraint and a gradient method to approximate a set 
    --          of points (AppDef_MultiLine) with a minimization of the
    --          sum(square(|F(i)-Qi|)) by changing the parameter. 
    --          The algorithm used is from of the mathematical 
    --          package: math_BFGS, a gradient method.



uses Vector                           from math, 
     MultipleVarFunctionWithGradient  from  math,
     MultiCurve                       from AppParCurves,
     HArray1OfConstraintCouple        from AppParCurves


raises OutOfRange from Standard,
       NotDone    from StdFail


private class ParLeastSquare instantiates LeastSquare from AppParCurves
    	(MultiLine, ToolLine);
	
private class ResConstraint instantiates ResolConstraint from AppParCurves
    	(MultiLine, ToolLine);

private class ParFunction instantiates Function from AppParCurves
    	(MultiLine, ToolLine, ParLeastSquare, ResConstraint);

class   Gradient_BFGS  from  AppParCurves 
    inherits   BFGS  from  math 
    uses  MultipleVarFunctionWithGradient  from math, 
    	  Vector                           from math
    is 
     
    	Create  (  F              :  in  out  MultipleVarFunctionWithGradient  from  math  ; 
	           StartingPoint  :           Vector   from  math  ; 
		   Tolerance3d	  :           Real     from  Standard  ; 
		   Tolerance2d	  :           Real     from  Standard  ; 
		   Eps    	  :           Real     from  Standard  ; 
		   NbIterations   :           Integer  from  Standard  = 200  ); 

        IsSolutionReached  ( me ; 
    	    	    	     F  :  in  out  MultipleVarFunctionWithGradient  from  math  ) 
		returns  Boolean  from  Standard  is  redefined  ; 

	fields 
	  
	  myTol3d  :  Real  from  Standard  ; 
	  myTol2d  :  Real  from  Standard  ; 
	 
        end  Gradient_BFGS  from  AppParCurves ;

is

    Create(SSP: MultiLine; FirstPoint, LastPoint: Integer;
    	   TheConstraints: HArray1OfConstraintCouple;
    	   Parameters: in out Vector; Deg: Integer; 
    	   Tol3d, Tol2d: Real; NbIterations: Integer = 200)
	---Purpose: Tries to minimize the sum (square(||Qui - Bi*Pi||)) 
	--          where Pui describe the approximating Bezier curves'Poles 
	--          and Qi the MultiLine points with a parameter ui.
	--          In this algorithm, the parameters ui are the unknowns.
	--          The tolerance required on this sum is given by Tol.
	--          The desired degree of the resulting curve is Deg.

    returns Gradient from AppParCurves;
    
    
    IsDone(me)
	---Purpose: returns True if all has been correctly done.	

    returns Boolean
    is static;
    
    
    Value(me)
    	---Purpose: returns all the Bezier curves approximating the
    	--          MultiLine SSP after minimization of the parameter.

    returns MultiCurve from AppParCurves
    raises NotDone from StdFail
    is static;
    
    
    Error(me; Index: Integer)
	---Purpose: returns the difference between the old and the new 
	--          approximation.
	--          An exception is raised if NotDone.
	--          An exception is raised if Index<1 or Index>NbParameters.

    returns Real
    raises NotDone from StdFail,
    	   OutOfRange from Standard
    is static;
    

    MaxError3d(me)
    	---Purpose: returns the maximum difference between the old and the 
    	--          new approximation.

    returns Real
    raises NotDone from StdFail
    is static;


    MaxError2d(me)
    	---Purpose: returns the maximum difference between the old and the 
    	--          new approximation.

    returns Real
    raises NotDone from StdFail
    is static;


    AverageError(me)
       ---Purpose: returns the average error between the old and the
       --          new approximation.

    returns Real
    raises NotDone from StdFail
    is static;


fields

SCU:          MultiCurve from AppParCurves;
ParError:     Vector from math;
AvError:      Real;
MError3d:     Real;
MError2d:     Real;
Done:         Boolean;

end Gradient from AppParCurves;