怎么理解下面这段matlab代码，并加以优化或者简化依旧能够达到运算结果

这串matlab代码怎么理解，并加以简化或者优化呢

单缝菲涅尔衍射实验光强分布模拟
lam=632.8nm，缝宽a=0.2mm，接受屏与观察屏间距z=1dm
解答区有源代码

clear all
lam=6.328e-7;
a=0.2e-3;
z=1e-1;
N=201;
M=91;
ym=0.5e-3;
y=linspace(-ym,ym,N);
beta1=-(2/(lamz))^0.5(a+y);
beta2=(2/(lamz))^0.5(a-y);
for i=1:N
t=1/(M-1)beta2(i);
p=linspace(0,beta2(i),M);
alfa=pi/2p.^2;
c2(i)=t*(sum(cos(alfa))-0.5cos(alfa(1))-0.5cos(alfa(M)));
end
for i=1:N
t=1/(M-1)beta1(i);
p=linspace(0,beta1(i),M);
alfa=pi/2p.^2;
c1(i)=t*(sum(cos(alfa))-0.5cos(alfa(1))-0.5cos(alfa(M)));
end
for i=1:N
t=1/(M-1)beta2(i);
p=linspace(0,beta2(i),M);
alfa=pi/2p.^2;
s2(i)=t*(sum(sin(alfa))-0.5sin(alfa(1))-0.5sin(alfa(M)));
end
for i=1:N
t=1/(M-1)beta1(i);
p=linspace(0,beta1(i),M);
alfa=pi/2p.^2;
s1(i)=t*(sum(sin(alfa))-0.5sin(alfa(1))-0.5sin(alfa(M)));
end
for i=1:N
B=0.25*((c2-c1).^2+(s2-s1).^2);
end
N=255;
subplot(1,2,1)
Br=(B/max(B))*N;
colormap(gray(N));
image(y,y,Br)
subplot(1,2,2)
plot(B,y)