MATLAB: Correct syntax for appending number to word in for loop

MATLAB

Hello,

I was wondering if somebody could help me with a for loop.

In the for loop below, what would be the correct syntax be to make the variable dt equal to dt1 in the first loop? How do you append a 1 onto the dt? So that dt = dt1?

Thank you for your help

Journeynumber=3;
dt1=2;
at1=4;
dt2=7;
at2=8;
for j=1:Journeynumber
      dt = dt"j";
end

Best Answer

for i = 1:10;
    str = ['dt' num2str(i)]
end

Related Solutions

MATLAB: How to determine number of iterations for steady state

I am not sure how you are saving the values inside the for-loop, but it seems that you are trying to integrate a function. You can check if it is the steady-state when the absolute change in value becomes less than a threshold value. For example,

L = 1;
n = 30;
dx = L/(n-1);
k = 1/(1.5*10^6);
K = 0.3;
dt = K*(dx^2/k);
T1 = zeros(1,n);
T2 = zeros(1,n);
T1(end)= 0;
T2(1) = -10;
for i=1:1000
    for j = 2:n-1
        dT = (dt*k/dx^2)*(T1(j+1) - 2*T2(j)+ T2(j-1));
        T2(j) = T1(j) + dT;
        if abs(dT) < 1e-3 % threshold reached.
            break
        end
    end
    T1 = T2;
end
plot(T1)

MATLAB: Columnwise ‘-append’

Could you simplify your input by creating the string first using MATLAB code and then use dlmwrite to add a single string? This might make it easier.

For clarity, here is what I'm thinking

for i=1:4
    fname = (sprintf('OutputFile_%d.txt',i));
    fin = Coordinates{i};
    time = Times{i};
    fileID = fopen(fname);
    for k = 1:n
        coordString = '';
        for j = 1:21
            coordString = [coordString ',' num2str(fin(k,j))];
        end
        timeString = '';
        for j = 1:24
            timeString = [timeString time(k,j)];
        end
        stringToAdd = [coordString timeString];
        end
        fprintf(fileID,'%s',stringToAdd);
    end
    fclose(fileID)
end

You can do some fancy indexing to avoid some of those for loops, but I left them there for clarity. The best part about this method is that it is easy to debug cause you can see each string you are about to write.

There may be a way to do it with dlmwrite, but I honestly don't know it (I welcome anyone to set me straight :) )

Hope this helps!

Best Answer

Related Solutions

MATLAB: How to determine number of iterations for steady state

MATLAB: Columnwise ‘-append’

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