bessl1a.m

主要阐述的是使用差分法解一类Bessel方程在不同边界条件下的离散解

clear;
Q=1,a=[2,1,0.6,0.5,0,-1],R=3,u=1;
w=sqrt(u)
for i=1:6
    b=1-a(i);
    A=0;
    B=Q/(a(i)*besselk(0,w)-b*w*besselk(1,w));
    x=-3:0.08:3;
    y=A*besseli(0,w*x)+B*besselk(0,w*x);
   switch i
        case 1,
            plot(x,y,'k');
        case 2,
            plot(x,y,' . k');
        case 3,
            plot(x,y,' * k');
        case 4,
            plot(x,y,' > k');
        case 5,
            plot(x,y,' + k');
        case 6,
            plot(x,y,' < k');
        end;
        hold on;
    end;
    hold off;
    axis([-1.5 1.5 -50 50]);
    legend('a= 2','a= 1','a= 0.6','a= 0.5','a= 0 ','a= - 1 ',0)
    title('第一种边界条件下不同a值的图象','FontSize',12,'FontName','隶书');