matlab_class/gcmfaces_misc/sym_g.m

function [field_out]=sym_g(field_in,sym_in,op_in);

%apply symmetry in the complex plane to field_in(z)
%       where field_in and z are in the complex arrays.
%then, depending on op_in, we apply a compensating operation
%
%format of field_in:
%               z(1,:) is z=-1+?i, z(end,:) is z=1+?i
%               z(:,1) is z=?-i, z(:,end) is z=?+i
%
%sym_in:        1,2,3,4 are reflexions about x=0,y=0,x=y,x=-y
%           4+nRot is rotation by nRot*pi/2
%op_in:         1       apply the opposite complex operation

field_out=field_in;
if isempty(whos('op_in')); op_in=0; end; 

if sym_in==1;
    field_out=flipdim(field_in,1);
    if op_in==1; field_out=-real(field_out)+i*imag(field_out); end;
elseif sym_in==2;
    field_out=flipdim(field_in,2);
    if op_in==1; field_out=real(field_out)-i*imag(field_out); end;
elseif sym_in==3;
    field_out=field_in.';
    if op_in==1; field_out=imag(field_out)+i*real(field_out); end;
elseif sym_in==4;
    field_out=flipdim(flipdim(field_in,1).',1);
    if op_in==1; field_out=-imag(field_out)-i*real(field_out); end;
elseif sym_in>=5&sym_in<=7;
    for icur=1:sym_in-4;
        field_out=flipdim(field_out.',1);
        if op_in==1; field_out=i*field_out; end;
    end
else;
    fprintf('error in sym_g2\n'); return;
end;

%for test case:
%--------------
%xx=[1:10]'*ones(1,10); yy=xx';
%zz=zeros(10,10); zz(1:2,1:3)=1; zz(8,9)=2; zz(2,6:8)=-1; zz(7,3)=-2;
%sym_g(zz,1); %etc
%with the following uncommented:
%-------------------------------
%figure;
%subplot(2,2,1); imagesc(field_in);
%subplot(2,2,4); imagesc(field_out);
%xlabel('y'); xlabel('x');


1	gforget	1.1	function [field_out]=sym_g(field_in,sym_in,op_in);
2
3			%apply symmetry in the complex plane to field_in(z)
4			% where field_in and z are in the complex arrays.
5			%then, depending on op_in, we apply a compensating operation
6			%
7			%format of field_in:
8			% z(1,:) is z=-1+?i, z(end,:) is z=1+?i
9			% z(:,1) is z=?-i, z(:,end) is z=?+i
10			%
11			%sym_in: 1,2,3,4 are reflexions about x=0,y=0,x=y,x=-y
12			% 4+nRot is rotation by nRot*pi/2
13			%op_in: 1 apply the opposite complex operation
14
15			field_out=field_in;
16	gforget	1.2	if isempty(whos('op_in')); op_in=0; end;
17	gforget	1.1
18			if sym_in==1;
19			field_out=flipdim(field_in,1);
20			if op_in==1; field_out=-real(field_out)+i*imag(field_out); end;
21			elseif sym_in==2;
22			field_out=flipdim(field_in,2);
23			if op_in==1; field_out=real(field_out)-i*imag(field_out); end;
24			elseif sym_in==3;
25			field_out=field_in.';
26			if op_in==1; field_out=imag(field_out)+i*real(field_out); end;
27			elseif sym_in==4;
28			field_out=flipdim(flipdim(field_in,1).',1);
29			if op_in==1; field_out=-imag(field_out)-i*real(field_out); end;
30			elseif sym_in>=5&sym_in<=7;
31			for icur=1:sym_in-4;
32			field_out=flipdim(field_out.',1);
33			if op_in==1; field_out=i*field_out; end;
34			end
35			else;
36			fprintf('error in sym_g2\n'); return;
37			end;
38
39			%for test case:
40			%--------------
41			%xx=[1:10]'*ones(1,10); yy=xx';
42			%zz=zeros(10,10); zz(1:2,1:3)=1; zz(8,9)=2; zz(2,6:8)=-1; zz(7,3)=-2;
43			%sym_g(zz,1); %etc
44			%with the following uncommented:
45			%-------------------------------
46			%figure;
47			%subplot(2,2,1); imagesc(field_in);
48			%subplot(2,2,4); imagesc(field_out);
49			%xlabel('y'); xlabel('x');
50
51