diff +scheme/Schrodinger1dCurve.m @ 429:dde5760863de feature/quantumTriangles

Added a scheme for the time deforming shrodinger equation in 1d
author Ylva Rydin <ylva.rydin@telia.com>
date Mon, 06 Feb 2017 09:54:18 +0100
parents
children 25053554524b
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/+scheme/Schrodinger1dCurve.m	Mon Feb 06 09:54:18 2017 +0100
@@ -0,0 +1,162 @@
+classdef Schrodinger1dCurve < scheme.Scheme
+    properties
+        m % Number of points in each direction, possibly a vector
+        h % Grid spacing
+        xi % Grid
+        order % Order accuracy for the approximation
+        grid
+        
+        D % non-stabalized scheme operator
+        H % Discrete norm
+        M % Derivative norm
+        alpha
+        
+        V_mat
+        D1
+        D2
+        Hi
+        e_l
+        e_r
+        d1_l
+        d1_r
+        gamm
+    end
+    
+    methods
+        % Solving SE in the form u_t = i*u_xx +i*V on deforming 1D domain;
+        function obj = Schrodinger1dCurve(m,order,V,constJi)
+            default_arg('V',0);
+            default_arg('constJi',false)
+            xilim={0 1};
+            if constJi
+                ops = sbp.D2Standard(m,xilim,order);
+            else
+                ops = sbp.D4Variable(m,xilim,order);
+            end
+            
+            obj.xi=ops.x;
+            obj.h=ops.h;
+            obj.D2 = ops.D2;
+            obj.D1 = ops.D1;
+            obj.H =  ops.H;
+            obj.Hi = ops.HI;
+            obj.M =  ops.M;
+            obj.e_l = ops.e_l;
+            obj.e_r = ops.e_r;
+            obj.d1_l = ops.d1_l;
+            obj.d1_r = ops.d1_r;
+            
+            
+            if isa(V,'function_handle')
+                V_vec = V(obj.x);
+            else
+                V_vec = obj.xi*0 + V;
+            end
+            
+            obj.V_mat = spdiags(V_vec,0,m,m);
+            
+            obj.D = @(a,a_xi,Ji) obj.d_fun(a, a_xi, Ji, constJi);
+            
+            obj.m = m;
+            obj.order = order;
+        end
+        
+        
+        % Closure functions return the opertors appliedo to the own doamin to close the boundary
+        % Penalty functions return the opertors to force the solution. In the case of an interface it returns the operator applied to the other doamin.
+        %       boundary            is a string specifying the boundary e.g. 'l','r' or 'e','w','n','s'.
+        %       type                is a string specifying the type of boundary condition if there are several.
+        %       data                is a function returning the data that should be applied at the boundary.
+        %       neighbour_scheme    is an instance of Scheme that should be interfaced to.
+        %       neighbour_boundary  is a string specifying which boundary to interface to.
+        
+        function [D] = d_fun(obj,a, a_xi , Ji , constJi)
+            if constJi
+                D= -0.5*(obj.D1*a - a_xi + a*obj.D1) + 1i*Ji*obj.D2 + 1i*obj.V_mat;
+              %  D= -a*obj.D1 + 1i*Ji*obj.D2 + 1i*obj.V_mat;
+            else
+                D= -0.5*(obj.D1*a - a_xi + a*obj.D1) + 1i*obj.D2(diag(Ji)) + 1i*obj.V_mat;
+              % D= - a*obj.D1 + 1i*obj.D2(diag(Ji)) + 1i*obj.V_mat;
+%               D=-obj.D1*a - a_xi + 1i*obj.D2(diag(Ji)) + 1i*obj.V_mat;
+            end
+        end
+        
+        function [closure, penalty] = boundary_condition(obj,boundary,type,data)
+            default_arg('type','dirichlet');
+            default_arg('data',0);
+            
+            [e,d,s,p] = obj.get_boundary_ops(boundary);
+            
+            switch type
+                % Dirichlet boundary condition
+                case {'D','d','dirichlet'}
+                    tau1 = s * 1i*d;
+                    tau2 = @(a) (-1*s*a(p,p) - abs(a(p,p)))/4*e;
+                    closure = @(a) obj.Hi*tau1*e' + obj.Hi*tau2(a)*e';
+                    
+                    switch class(data)
+                        case 'double'
+                            penalty = @(a) -(obj.Hi*tau1*data+obj.Hi*tau2(a)*data);
+                            %                      case 'function_handle'
+                            %                           penalty = @(t)-obj.Hi*tau*data(t);
+                        otherwise
+                            error('Wierd data argument!')
+                    end
+                    
+                    % Unknown, boundary condition
+                otherwise
+                    error('No such boundary condition: type = %s',type);
+            end
+        end
+        
+        function [closure, penalty] = interface(obj,boundary,neighbour_scheme,neighbour_boundary)
+            % u denotes the solution in the own domain
+            % v denotes the solution in the neighbour domain
+            %             [e_u,d_u,s_u] = obj.get_boundary_ops(boundary);
+            %             [e_v,d_v,s_v] = neighbour_scheme.get_boundary_ops(neighbour_boundary);
+            
+            %             a =  -s_u* 1/2 * 1i ;
+            %             b =  a';
+            
+            %             tau = b*d_u;
+            %             sig = -a*e_u;
+            
+            %             closure = obj.Hi * (tau*e_u' + sig*d_u');
+            %             penalty = obj.Hi * (-tau*e_v' - sig*d_v');
+        end
+        
+        % Ruturns the boundary ops and sign for the boundary specified by the string boundary.
+        % The right boundary is considered the positive boundary
+        function [e,d,s,p] = get_boundary_ops(obj,boundary)
+            switch boundary
+                case 'l'
+                    e = obj.e_l;
+                    d = obj.d1_l;
+                    s = -1;
+                    p=1;
+                case 'r'
+                    e = obj.e_r;
+                    d = obj.d1_r;
+                    s = 1;
+                    p=obj.m;
+                otherwise
+                    error('No such boundary: boundary = %s',boundary);
+            end
+        end
+        
+        function N = size(obj)
+            N = obj.m;
+        end
+        
+    end
+    
+    methods(Static)
+        % Calculates the matrcis need for the inteface coupling between boundary bound_u of scheme schm_u
+        % and bound_v of scheme schm_v.
+        %   [uu, uv, vv, vu] = inteface_couplong(A,'r',B,'l')
+        function [uu, uv, vv, vu] = interface_coupling(schm_u,bound_u,schm_v,bound_v)
+            [uu,uv] = schm_u.interface(bound_u,schm_v,bound_v);
+            [vv,vu] = schm_v.interface(bound_v,schm_u,bound_u);
+        end
+    end
+end
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