-- File:	Uzawa.cdl
-- Created:	Thu Aug 22 10:44:47 1991
-- Author:	Laurent PAINNOT
--		<lpa@topsn3>
---Copyright:	 Matra Datavision 1991, 1992



class Uzawa from math

    ---Purpose: This class implements a system resolution C*X = B with
    --          an approach solution X0. There are no conditions on the 
    --          number of equations. The algorithm used is the Uzawa 
    --          algorithm. It is possible to have equal or inequal  (<)
    --          equations to solve. The resolution is done with a 
    --          minimization of Norm(X-X0).
    --          If there are only equal equations, the resolution is directly
    --          done and is similar to Gauss resolution with an optimisation
    --          because the matrix is a symmetric matrix.
    --          (The resolution is done with Crout algorithm)



uses Matrix from math, 
     Vector from math,
     OStream from Standard

raises NotDone from StdFail,
       ConstructionError from Standard

is

    Create(Cont: Matrix; Secont, StartingPoint: Vector; 
    	   EpsLix: Real = 1.0e-06; EpsLic: Real = 1.0e-06;
	   NbIterations: Integer = 500)
	    ---Purpose: Given an input matrix Cont, two input vectors Secont
	    --          and StartingPoint, it solves Cont*X = Secont (only
	    --          = equations) with a minimization of Norme(X-X0).
	    --          The maximun iterations number allowed is fixed to 
	    --          NbIterations.
	    --          The tolerance EpsLic is fixed for the dual variable 
	    --          convergence. The tolerance EpsLix is used for the 
	    --          convergence of X.
	    --          Exception ConstuctionError is raised if the line number
	    --          of Cont is different from the length of Secont.
	  
    returns Uzawa
    raises ConstructionError;
    
    
    Create(Cont: Matrix; Secont, StartingPoint: Vector; Nci, Nce: Integer;
    	   EpsLix: Real = 1.0e-06; EpsLic: Real = 1.0e-06; 
           NbIterations: Integer = 500)
	    ---Purpose: Given an input matrix Cont, two input vectors Secont
	    --          and StartingPoint, it solves Cont*X = Secont (the Nce
	    --          first equations are equal equations and the Nci last 
	    --          equations are inequalities <) with a minimization
	    --          of Norme(X-X0).
	    --          The maximun iterations number allowed is fixed to 
	    --          NbIterations.
	    --          The tolerance EpsLic is fixed for the dual variable 
	    --          convergence. The tolerance EpsLix is used for the 
	    --          convergence of X.
	    --          There are no conditions on Nce and Nci.
	    --          Exception ConstuctionError is raised if the line number
	    --          of Cont is different from the length of Secont and from
	    --          Nce + Nci.

    returns Uzawa
    raises ConstructionError;


    Perform(me: in out; Cont: Matrix; Secont, StartingPoint: Vector; 
            Nci, Nce: Integer; EpsLix: Real = 1.0e-06; 
            EpsLic: Real = 1.0e-06; NbIterations: Integer = 500)
	    ---Purpose: Is used internally by the two constructors above.

    is static protected;
    
	
    IsDone(me)
    	---Purpose: Returns true if the computations are successful, otherwise returns false.
      	---C++: inline
    returns Boolean
    is static;
    
    
    Value(me) 
    	---Purpose: Returns the vector solution of the system above.
    	--          An exception is raised if NotDone.
        ---C++: inline
    	---C++: return const&    
    returns Vector
    raises NotDone
    is static;
    

    InitialError(me)
    	---Purpose: Returns the initial error Cont*StartingPoint-Secont.
    	--          An exception is raised if NotDone.
        ---C++: inline
    	---C++: return const&
    returns Vector
    raises NotDone
    is static;
    
    
    Duale(me; V : out Vector)
    	---Purpose: returns the duale variables V of the systeme.
    
    raises NotDone
    is static;
    
    
    Error(me)
    	---Purpose: Returns the difference between X solution and the 
    	--          StartingPoint.
    	--          An exception is raised if NotDone.
        ---C++: inline
    	---C++: return const&
    returns Vector
    raises NotDone
    is static;
     
     
    NbIterations(me)
    	---Purpose: returns the number of iterations really done.
    	--          An exception is raised if NotDone.
    	---C++: inline
    returns Integer
    raises NotDone
    is static;
    
    
    InverseCont(me)
    	---Purpose: returns the inverse matrix of (C * Transposed(C)).
    	--          This result is needed for the computation of the gradient
    	--          when approximating a curve.
        ---C++: inline
    	---C++: return const&
    returns Matrix
    raises NotDone
    is static;


    Dump(me; o: in out OStream)
    	---Purpose: Prints information on the current state of the object.

    is static;



fields

Resul :   Vector;
Erruza:   Vector;
Errinit:  Vector;
Vardua:   Vector;
CTCinv:   Matrix;
NbIter :  Integer;
Done:     Boolean;

end Uzawa;