# Error using + Matrix dimensions must agree. I want to find the value of Mt. Kindly help me clear the error.

1 view (last 30 days)
Swathi S on 4 Feb 2021
Answered: VBBV on 29 Oct 2021
CODE:
a=0.1
s=0.01
N=5
wd=0.002906
d=5
for a1=a-((N-1)*(wd+s)):(wd+s):a
for b1=a-((N-1)*(wd+s)):(wd+s):a
r1=@(x,y) sqrt((x+a1).^2+(y+b1).^2+d.^2)
r2=@(x,y) sqrt((a1-x).^2+(y+b1).^2+d.^2)
r3=@(x,y) sqrt((a1-x).^2+(y-b1).^2+d.^2)
r4=@(x,y) sqrt((x+a1).^2+(y-b1).^2+d.^2)
C1=@(x) a1+x
C4=@(x) -a1-x
C2=@(x) a1-x
C3=@(x) -a1+x
d1=@(y) y+b1
d2=@(y) y+b1
d3=@(y) y-b1
d4=@(y) y-b1
fun=@(x,y) ((((u./(4.*pi)).*((((((-1).^1).*d1(y))./(r1(x,y).*(r1(x,y)+((-1).^(1.+1)).*C1(x))))-(C1(x)./(r1(x,y).*(r1(x,y)+d1(y)))))+(((((-1).^2).*d2(y))./(r2(x,y).*(r2(x,y)+(((-1).^(2.+1))).*C2(x))))-(C2(x)./(r2(x,y).*(r2(x,y)+d2(y)))))+(((((-1).^3).*d3(y))./(r3(x,y).*(r3(x,y)+(((-1).^(3.+1))).*C3(x))))-(C3(x)./(r3(x,y).*(r3(x,y)+d3(y)))))+(((((-1).^4).*d4(y))./(r4(x,y).*(r4(x,y)+((-1).^(4.+1)).*C4(x))))-(C4(x)./(r4(x,y).*(r4(x,y)+d4(y)))))))));
M = integral2(fun,-b1,b1,-b1,b1)
Mt=Mt+M
end
end
ERROR:
Error using +
Matrix dimensions must agree.
Error in @(x,y)sqrt((x+a1).^2+(y+b1).^2+d.^2)
Error in
@(x,y)((((u./(4.*pi)).*((((((-1).^1).*d1(y))./(r1(x,y).*(r1(x,y)+((-1).^(1.+1)).*C1(x))))-(C1(x)./(r1(x,y).*(r1(x,y)+d1(y)))))+(((((-1).^2).*d2(y))./(r2(x,y).*(r2(x,y)+(((-1).^(2.+1))).*C2(x))))-(C2(x)./(r2(x,y).*(r2(x,y)+d2(y)))))+(((((-1).^3).*d3(y))./(r3(x,y).*(r3(x,y)+(((-1).^(3.+1))).*C3(x))))-(C3(x)./(r3(x,y).*(r3(x,y)+d3(y)))))+(((((-1).^4).*d4(y))./(r4(x,y).*(r4(x,y)+((-1).^(4.+1)).*C4(x))))-(C4(x)./(r4(x,y).*(r4(x,y)+d4(y)))))))))
Error in integral2Calc>integral2t/tensor (line 228)
Z = FUN(X,Y); NFE = NFE + 1;
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 test (line 110)
M = integral2(fun,-b1,b1,-b1,b1)
Rik on 4 Feb 2021
You can simulate what we will see by using clearvars before you run the code that you pasted here.

Shiva Kalyan Diwakaruni on 10 Feb 2021
Hi,
You can try declaring and defining variables like u and Mt to see if the code is working . Error is occuring due to variable u and Mt not being defined.
thanks.

VBBV on 29 Oct 2021
a=1.5; % make good guess
s=0.01;
N=5;
wd=0.002906;
d=5;
u=2; % guess
i = 1;
a1=a-((N-1)*(wd+s)):(wd+s):a;
b1=a-((N-1)*(wd+s)):(wd+s):a
b1 = 1×5
1.4484 1.4613 1.4742 1.4871 1.5000
for a1=a-((N-1)*(wd+s)):(wd+s):a
for b1=a-((N-1)*(wd+s)):(wd+s):a
r1=@(x,y) sqrt((x+a1).^2+(y+b1).^2+d.^2);
r2=@(x,y) sqrt((a1-x).^2+(y+b1).^2+d.^2);
r3=@(x,y) sqrt((a1-x).^2+(y-b1).^2+d.^2);
r4=@(x,y) sqrt((x+a1).^2+(y-b1).^2+d.^2);
C1=@(x) a1+x;
C4=@(x) -a1-x;
C2=@(x) a1-x;
C3=@(x) -a1+x;
d1=@(y) y+b1;
d2=@(y) y+b1;
d3=@(y) y-b1;
d4=@(y) y-b1;
fun=@(x,y) ((((u./(4.*pi)).*((((((-1).^1).*d1(y))./(r1(x,y).*(r1(x,y)+((-1).^(1+1)).*C1(x))))-(C1(x)./(r1(x,y).*(r1(x,y)+d1(y)))))+(((((-1).^2).*d2(y))./(r2(x,y).*(r2(x,y)+(((-1).^(2+1))).*C2(x))))-(C2(x)./(r2(x,y).*(r2(x,y)+d2(y)))))+(((((-1).^3).*d3(y))./(r3(x,y).*(r3(x,y)+(((-1).^(3+1))).*C3(x))))-(C3(x)./(r3(x,y).*(r3(x,y)+d3(y)))))+(((((-1).^4).*d4(y))./(r4(x,y).*(r4(x,y)+((-1).^(4+1)).*C4(x))))-(C4(x)./(r4(x,y).*(r4(x,y)+d4(y)))))))));
M(i)= integral2(fun,-b1,b1,-b1,b1); % integral value for each iteration
i=i+1;
end
end
M
M = 1×25
0.1347 0.1379 0.1411 0.1444 0.1477 0.1358 0.1390 0.1422 0.1455 0.1488 0.1368 0.1401 0.1433 0.1466 0.1500 0.1379 0.1411 0.1444 0.1478 0.1511 0.1389 0.1422 0.1455 0.1489 0.1523
Mt = sum(M)
Mt = 3.5840
plot(M);

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