I'm getting error message 'In an assignment A(I) = B, the number of elements in B and I must be the same, Error in BM3D (line 25) Y(i+1)=Y(i​)*(1-k/(6*​pi))+sqrt(​12*pi/delt​at)*m1*del​tat/(6*pi)​; '... Can someone please help me to correct my mist

clear all
clc
k=1;
deltat=1;%time interval
tmax=200;
N=input('enter the no of iteations required = ')
X=zeros(1,2*(tmax+2));%initaial position set to 0
Y=zeros(1,2*(tmax+2));%initaial position set to 0
Z=zeros(1,2*(tmax+2));%initaial position set to 0

for K=1:N
for i=1:2:tmax
    x1=rand(1);
    x2=rand(1);
    y1=rand(1);
    y2=rand(2);
    z1=rand(1);
    z2=rand(2);
    n1=((sqrt(-2*log(x1)))*(cos(2*pi*x2)));  
    n2=((sqrt(-2*log(x1)))*(sin(2*pi*x2)));
    X(i+1)=X(i)*(1-k/(6*pi))+sqrt(12*pi/deltat)*n1*deltat/(6*pi);
    X(i+2)= X(i+1)*(1-(k/(6*pi)))+sqrt(12*pi/deltat)*n2*deltat/(6*pi);   
    m1=((sqrt(-2*log(y1)))*(cos(2*pi*y2)));  
    m2=((sqrt(-2*log(y1)))*(sin(2*pi*y2)));
    Y(i+1)=Y(i)*(1-k/(6*pi))+sqrt(12*pi/deltat)*m1*deltat/(6*pi);
    Y(i+2)= Y(i+1)*(1-(k/(6*pi)))+sqrt(12*pi/deltat)*m2*deltat/(6*pi);   
    l1=((sqrt(-2*log(z1)))*(cos(2*pi*z2)));  
    l2=((sqrt(-2*log(z1)))*(sin(2*pi*z2)));
    Z(i+1)=Z(i)*(1-k/(6*pi))+sqrt(12*pi/deltat)*l1*deltat/(6*pi);
    Z(i+2)= Z(i+1)*(1-(k/(6*pi)))+sqrt(12*pi/deltat)*l2*deltat/(6*pi);   
end
s=zeros(1,tmax+1);
for i=1:tmax+1
        s(1)=0;sy(1)=0;sz(1)=0;
for j=2:tmax+2
     s(i)=s(i)+X(j)*X(j+i);
     sy(i)=sy(j)+Y(j)*Y(j+1);
     sz(i)=sz(k)+Z(j)*Y(j+1);
end

end
for i=1:tmax
    avx(K,i)=s(i)/tmax;
    avy(K,i)=sy(i)/tmax;
    avz(K,i)=sz(i)/tmax;
end 

end

for n=2:tmax
    M1(n)=mean(avx(:,n));
    M2(n)=mean(avy(:,n));
    M3(n)=mean(avz(:,n));
end

hold on
xlabel('time(t)')
ylabel('<x(t)x(0)>')
title('Autocorrelation')
x =2:tmax;  
y=exp(-x/(6*pi));
plot(x,y,'LineWidth',4)
plot(x,M1(x),'g')
plot(x,M2(x),'r')
plot(x,M3(x),'k')

[Matthew Eicholtz]

I would suggest trying to pose your question and description in a more pleasing way to readers. Cut-and-pasted error messages in the title makes it difficult for people to help you.

Answer 1

[Matt J]

In

    Y(i+1)=Y(i)*(1-k/(6*pi))+sqrt(12*pi/deltat)*m1*deltat/(6*pi);

The left hand side is a scalar location but the right hand side is a 2x2 matrix, because m1 is a 2x2 matrix. You cannot park a 2x2 car in a 1x1 parking space.

Answer 2

[Matthew Eicholtz]

• Your current error is due to the fact that your code attempts to assign a 2x2 array to a single element in the vector Y.
• The reason the right side of the equation in line 25 is a 2x2 array is because of m1.
• m1 is a 2x2 array because of y2
• If you change line 16 and line 18 to rand(1) instead of rand(2), this fixes your current error. However, when I run the code again, a new error appears elsewhere.

You should clarify what you are trying to do.