summation of valuse in nested loops

Hello,

I have three nested loop (I change from 1-10, J change from 1-20 and K change from 1-100) I saved the result from J,K loops in matrix (20,100). When loop went to I again I want to sum the old value with new value. For example

new A(1,1)=old A(1,1)+U(j,k) for new I loop.

I used below code and I do not know if it is correct. Please can you suggest new one or correct mine

A(20,100)=0
U(20,100)=0
for i=1:10
    for j=1:20
        for k=1:100
            A(j,k)=A(j,k)+U(j,k)
        end
    end
end

[Star Strider]

Please go into more detail on what you intend with:

new A(1,1)=old A(1,1)+U(j,k) for new I loop.

What should the other elements of ‘A’ be? Do you intend:

new A(l,m)=old A(l,m)+U(j,k) for new I loop?

That could require four nested loops. MATLAB can certainly do that, but there could be more efficient ways than nested loops.

[Ali Kareem]

Hi,

Thank you for your reply.

I want to save output from equation in matrix A(20,100) this is for loops (J,K). So this matrix A(20,100) will repeated for ten times. each time I want to add the output from old matrix to new one for all cell (each cell will add to same old cell) for all cell in all raw and column.

new A(1,1)=old A(1,1)+U(j,k) ....to .. new A(1,20)=old A(1,20)+U(j,k)

new A(100,1)=old A(100,1)+U(j,k) ... new A(100,20)=old A(100,20)+U(j,k)

 A(20,100)=0

 U(20,100)=0

 z=3

 for i=1:10
    for j=1:20
        for k=1:100
            U(j,k)=z^2+sin(j)
            A(j,k)=A(j,k)+U(j,k)
        end
    end
end

for I=1 I will get from (j,k) loops below matrix

A(1,1) A(1,2) A(1,3)…… A(1,100)

A(2,1) A(2,2) A(2,3)…… A(2,100)

A(20,1) A(20,2) A(20,3)…… A(20,100)

When I=2 I want to add each new cell like (A(1,1)) to old cell to new cell ( I mean for I repeated ten times then there will be 10 values for each cell like A(1,1) when I=1, then A(1,1) when I =2….and so on until I=10). I want to have summation for these values. (I mean by old the previous matrix when I=2 the previous matrix is when I =1 and so on until I=10)

A(1,1) A(1,2) A(1,3)…… A(1,100)

A(2,1) A(2,2) A(2,3)…… A(2,100)

Thank you so much A(20,1) A(20,2) A(20,3)…… A(20,100)

Answer 1

[Andrei Bobrov]

z = 3;

ii = 10;
jj = 20;
k = 100;

z2 = z^2;
A = (z2+sin(1:jj)'*ones(1,k))*ii;

[Ali Kareem]

Hello,

Thank you for your reply. Please I do not think my question was clear. Below what I want to do

 for L=1:10                 
for i=1:20

    for j=1:100              

        r=(Xc+Y)^(1/2);
        VC=VCo*(1-(exp(-(r))));
        Uf(i,j)=(((VC-Yc))/((pi)*(r)));
        Vf(i,j)=((VC*r)*(Xc))/((2*pi));
        Uft(i,j)=Uft(i,j)+Uf(i,j);
        Vft(i,j)=Vft(i,j)+Vf(i,j);
        Ufz(i,j)=(U-Uft(i,j))/U;

    end;  
end;
end;

I Want to have summation of Uft and Vft. so for the entire loops (i,j) I will get the first matrix (20,100) then after that for L loop I will get the other matrices. I want Uft(1,1) to add to the Uft(1,1) from old matrix until end of loop L (this mean for ten times)

this scenario for for new A(1,2)=old A(1,2) and so on

[Andrei Bobrov]

What is it: Xc, Yc, Y, VCo, U.

[Ali Kareem]

Hi, Thank you for your reply. Xc, Yc, Y, VCo, U. all these are calculated in another part of program.

Regards

[Andrei Bobrov]

Xc, Yc, Y, VCo, U - arrays or constants?

[Ali Kareem]

Hi,

Thank you for your reply. U,VCo constant. Xc,Yc,Y arrays.

Regards

[Andrei Bobrov]

Hi Ali! What is the size of your arrays (Xc,Yc,Y)?

:)