由于左侧的索引与右侧的大小不兼容，无法执行分配

Question

When I gave four lambda values then it gives me an error that it's Unable to perform assignment because the indices on the left side are not compatible with the size of the right side. But for a single value like 36, 38, 40, or 42 it's ok.

R = [0.5:0.1:2.25];
    Vs1= [120];
    Vs2 = R.*Vs1;
    H1=[5:5:25];
    rho = [2000 2000];
    lambda = [36 38 40 42];

    for j=1:length(Vs2),
        Vs = [Vs1 Vs2(j)];
        for i=1:length(H1)
            H2=30-H1(i);
            d=[H1(i),H2];
            Vs30(j,i)=Vs30_fun(d,Vs);
            
        end
    end
    
    
    for j=1:length(Vs2),
        Vs = [Vs1 Vs2(j)];Vp=2.*Vs;
        for i=1:length(H1)
            d=[H1(i) Inf];
            VR(j,i)=lv_fun(d,Vs,Vp,rho,lambda);
            
        end
    end
    
    M=VR<Vs30;
    [m,n]=size(M);
    VR=zeros(length(Vs2),length(H1));
    for i=1:m
        for j=1:n        
            if M(i,j)==0
                plot(H1(i),R(j), 'r*')
                hold on
    %                drawnow();
            end
        end
    end

Answer 1

 VR(j,i)=lv_fun(d,Vs,Vp,rho,lambda);

You didn't initialize VR. I suggest you initialize the variable before and plugin values later. try this before the loop.

VR=zeros(length(Vs2),length(H1));