entryp.m

非连续波导时间域有限差分法仿真（TD-FDM）

% generate every entry for matrix P

%function entryP(i,j,tag,nmbr,a,b,c)

        [center,down,upper,left,right] = getNmbr(i,j,tag,nmbr);
        
        switch tag
            case inf
                % do nothing
            case 0                                          % for non-boundary nodes
                P(center,center) = c;
                P(center,down) = b;    P(center,upper) = b;
                P(center,left) = a;    P(center,right) = a;
            case 1                                          % edge nodes NOW (excluding corner nodes)
                P(center,center) = c;
                P(center,upper) = 2*b;
                P(center,left) = a;    P(center,right) = a;
            case 2
                P(center,center) = c;
                P(center,down) = 2*b;
                P(center,left) = a;    P(center,right) = a;
            case 3
                P(center,center) = c;
                P(center,down) = b;    P(center,upper) = b;
                P(center,right) = 2*a;
            case 4
                P(center,center) = c;
                P(center,down) = b;    P(center,upper) = b;
                P(center,left) = 2*a;
            case 5
                P(center,center) = c;
                P(center,down) = b;    P(center,upper) = b;
                P(center,right) = 2*a;
            case 6
                P(center,center) = c;
                P(center,down) = b;    P(center,upper) = b;
                P(center,left) = 2*a;
            case 7                                          % corner nodes NOW
                P(center,center) = c;
                P(center,upper) = 2*b;
                P(center,right) = 2*a;
            case 8
                P(center,center) = c;
                P(center,down) = 2*b;
                P(center,right) = 2*a;
            case 9
                P(center,center) = c;
                P(center,down) = 2*b;
                P(center,left) = 2*a;
            case 10
                P(center,center) = c;
                P(center,upper) = 2*b;
                P(center,left) = 2*a;
            otherwise
                error('I dont know how to do then if there is an error here...');
        end