# MATLAB: Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 101-by-101.

## MATLAB: Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 101-by-101.

cfdindexunable to perform assignment

Hello
I have problem with my code and I can’t find the right solution. even if I’ve change my matrices to a uniform one (like 100*100)
I will be appreciate you if you answer.
best wishes
``clcclear allclose allID = 80;Q = 2/(30*24*60*60);        k = (ID * 10)/(30*24*60*60);       D = 0.02 * ID;                              S = 0.018;                                  xmin = 0; ymin = 0;             xmax = 20000; ymax = 20000;     nSS = 100;                      dx = xmax / nSS;               dy = dx;                        dt = 1000;                      Tmax = 30*24*60*60;             nTS = Tmax / dt;               xw = 10000;yw1 = 5000;yw2 = 15000;xp1 = 5000;xp2 = 15000;yp = 10000;h = 80*ones(20000/dx +1 , 20000/dy +1 );for t = 1:nTS    for i = 2:nSS        for j = 2:nSS            if i == xw/dx +1 && j == yw1/dy +1                  h(i,j) = (1/(S*dx*dy))*(((k*0.5*dt)*(dy*(((h(i+1,j)^2)-(2*(h(i,j)^2))+...                      (h(i-1,j)^2))/dx)+dx*(((h(i,j+1)^2)-(2*(h(i,j)^2))+(h(i,j-1)^2))/dy)))-dx*dy*dt*Q)+h(j,i);            elseif i == xw/dx +1 &&  j == yw2/dy +1                  h(i,j) = (1/(S*dx*dy))*(((k*0.5*dt)*(dy*(((h(i+1,j)^2)-(2*(h(i,j)^2))+...                      (h(i-1,j)^2))/dx)+dx*(((h(i,j+1)^2)-(2*(h(i,j)^2))+(h(i,j-1)^2))/dy)))-dx*dy*dt*Q)+h(j,i);            elseif i == xw/dx +1 &&  j>= yw1/dy && j<=yw2/dy                  h(i,j) = (1/(S*dx*dy))*(((k*0.5*dt)*(dy*(((h(i-1,j)^2)-(2*(h(i,j)^2))+...                      (h(i-1,j)^2))/dx)+dx*(((h(i,j+1)^2)-(2*(h(i,j)^2))+(h(i,j-1)^2))/dy)))-dx*dy*dt*Q)+h(j,i);            else                  h(i,j) = (1/(S*dx*dy))*(((k*0.5*dt)*(dy*(((h(i+1,j)^2)-(2*(h(i,j)^2))+...                      (h(i-1,j)^2))/dx)+dx*(((h(i,j+1)^2)-(2*(h(i,j)^2))+(h(i,j-1)^2))/dy))))+h(j,i);                end        end    endendu = zeros(101);v = zeros(101);for t=1:nTS    for i=1:nSS        for j=1:nSS            if i>=1 && i<=101 && j==1            u(i,j)=0;            v(i,j)=0;             elseif i>=1 && i<=101 && j==101            u(i,j)=0;            v(i,j)=0;             elseif i==101 && j>=1 && j<=101              u(i,j)=0;            v(i,j)=0;             elseif i==1 && j>=1 && j<=101            u(i,j)=0;            v(i,j)=0;             elseif i>= yw1/dy && i<=yw2/dy && j == xw/dx +1               v(i,j)=0;            else            v(i,j) = (k*dy*dt)*(((h(i+1,j)+h(i,j))/2)-((h(i,j)+h(i-1,j))/2));            u(i,j) = (k*dx*dt)*(((h(i,j+1)+h(i,j))/2)-((h(i,j)+h(i,j-1))/2));            end        end    endendc = zeros(101);a1 = 1;b1 = 1;c1 = 1;d1 = 1;Q = zeros(101);Q(51,24) = 2;Q(51,76) = 2;for t=1:nTS    for i=2:100        for j=2:100            if v(i,j)<0                a1 = 1;                b1 = 0;            else                a1 = 0;                b1 = 1;            end            if u(i,j)<0               c1 = 1 ;               d1 = 0 ;            else                c1 = 0;                d1 = 1;            end             c(i,j)=c(i,j)+((D*dt)/dx)*(((c(i+1,j)-c(i,j))/dx)-(c(i,j)-c(i-1,j))/dx)+...             +((D*dt)/dx)*(((c(i,j+1)-c(i,j))/dx)-(c(i,j)-c(i,j-1))/dx)-...             ((k*v*dt)/(dx))*0.5*(a1*(c(i+1,j)-c(i,j))-b1*(c(i,j)-c(i-1,j)))-...             ((k*u*dt)/(dy))*0.5*(c1*(c(i,j+1)-c(i,j))-d1*(c(i,j)-c(i,j-1)))+Q;        end    endend``

• ``             c(i,j)=c(i,j)+((D*dt)/dx)*(((c(i+1,j)-c(i,j))/dx)-(c(i,j)-c(i-1,j))/dx)+...             +((D*dt)/dx)*(((c(i,j+1)-c(i,j))/dx)-(c(i,j)-c(i,j-1))/dx)-...             ((k*v*dt)/(dx))*0.5*(a1*(c(i+1,j)-c(i,j))-b1*(c(i,j)-c(i-1,j)))-...             ((k*u*dt)/(dy))*0.5*(c1*(c(i,j+1)-c(i,j))-d1*(c(i,j)-c(i,j-1)))+Q;``