Integrand output size does not match the input size. Kindly help me clear the error.

CODE:

%all variables are declared
for ai=a-2*(N-1)*wd-2*(N-1)*s:2*(wd+s):a-2*(N-N)*wd-2*(N-N)*s
for aj=a-2*(N-1)*wd-2*(N-1)*s:2*(wd+s):a-2*(N-N)*wd-2*(N-N)*s
Bz= @(x,y) (((u./(4.*pi)).*((((((-1).^1).*d1(ai))./(r1(ai).*(r1(ai)+((-1).^(1+1)).*C1(ai))))-(C1(ai)./(r1(ai).*(r1(ai)+d1(ai)))))+(((((-1).^2).*d2(ai))./(r2(ai).*(r2(ai)+(((-1).^(2+1))).*C2(ai))))-(C2(ai)./(r2(ai).*(r2(ai)+d2(ai)))))+(((((-1).^3).*d3(ai))./(r3(ai).*(r3(ai)+(((-1).^(3+1))).*C3(ai))))-(C3(ai)./(r3(ai).*(r3(ai)+d3(ai)))))+(((((-1).^4).*d4(ai))./(r4(ai).*(r4(ai)+((-1).^(4+1)).*C4(ai))))-(C4(ai)./(r4(ai).*(r4(ai)+d4(ai))))))))
M=integral2(Bz,-aj,aj,-aj,aj) 
       Mtl=Mtl+M
       Mtotal=(Mtl./2).*J.*G
hold on
        end
     end

ERROR:

Error using integral2Calc>integral2t/tensor (line 241)

Integrand output size does not match the input size.

Error in integral2Calc>integral2t (line 55)

[Qsub,esub] = tensor(thetaL,thetaR,phiB,phiT);

Error in integral2Calc (line 9)

[q,errbnd] = integral2t(fun,xmin,xmax,ymin,ymax,optionstruct);

Error in integral2 (line 106)

Q = integral2Calc(fun,xmin,xmax,yminfun,ymaxfun,opstruct);

Error in FPSSCFINAL10Sep192 (line 108)

M=integral2(Bz,-aj,aj,-aj,aj)

[Walter Roberson]

You have

Bz= @(x,y) (((u./(4.*pi)).*((((((-1).^1).*d1(ai))./(r1(ai).*(r1(ai)+((-1).^(1+1)).*C1(ai))))-(C1(ai)./(r1(ai).*(r1(ai)+d1(ai)))))+(((((-1).^2).*d2(ai))./(r2(ai).*(r2(ai)+(((-1).^(2+1))).*C2(ai))))-(C2(ai)./(r2(ai).*(r2(ai)+d2(ai)))))+(((((-1).^3).*d3(ai))./(r3(ai).*(r3(ai)+(((-1).^(3+1))).*C3(ai))))-(C3(ai)./(r3(ai).*(r3(ai)+d3(ai)))))+(((((-1).^4).*d4(ai))./(r4(ai).*(r4(ai)+((-1).^(4+1)).*C4(ai))))-(C4(ai)./(r4(ai).*(r4(ai)+d4(ai))))))))

The calculations on the right hand side do not use x or y, so whatever it returns is not going to be the same size as x and y

The function you pass into integral2() is not passed scalar x and y: it is passed arrays of x and y that are the same size, and it is responsible for returning a result that is the same size as x.