Magnatic field in surface coil for overlapping conductor

Dear All

Please can you help urgently

I do not know where is the error.

clear all close all condition = 1;

while (condition)

    L = input('Please enter the grid length and size [l s]: ');
    N = L(2);   l = L(1);     dl = l/N;
    miu0 = 4*pi*1e-7/1000;
    I1 = 1;  I2 = -1;    width = 1/dl;

    %%Grid Calculations. 
    offset = input('Please enter the position for wire 1 in cm:  ');
    offset = ceil(offset/dl);
    overlap = input('Please enter the %age Overlap between two coils: ');
    overlap = overlap*N/100;
    n_slices = input('Please enter the number of slices: ');
    loc = input('Please enter the location of the first slice in mm: ');
    loc = ceil(loc/(10*dl));
     x= -N/2:N/2;
    y=-N/2:N/2;

    % Setting Location of the wire points. 
    p11 = offset;
    p12 = p11+width;
    mid1 = p11+width/2;
    mid2 = mid1 + ceil((1-overlap/100)*width);
    p21 = mid2-width/2;
    p22 = p21+width;
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    if ((p11<0) || (p12<0) || (p21<0) || (p22<0) || (p11>N+1) || (p12>N+1) || (p21>N+1) || (p22>N+1))
        disp('%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%')
        disp('Wires do not fit on the grid, Please enter new dimensions')
        disp('%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%')
    else
        condition = 0;
        for i = 1: length(x)
            for j = 1: length(y)

                % Calculating distance vectors
                r1(i,j) = sqrt((x(p11) - x(i))^2 + (y(j))^2);
                r2(i,j) = sqrt((x(p12) - x(i))^2 + (y(j))^2);
                r3(i,j) = sqrt((x(p21) - x(i))^2 + (y(j))^2);
                r4(i,j) = sqrt((x(p22) - x(i))^2 + (y(j))^2);

            end
        end

        %Calculating magentic fields
        B1 = (miu0*I1)./(2*pi*r1);
        B2 = (miu0*I2)./(2*pi*r2);
        B3 = (miu0*I2)./(2*pi*r3);
        B4 = (miu0*I1)./(2*pi*r4);
        B = B1+B2+B3+B4;
        % Selecting reference axis
        Ref_axis = B(N/2+1:N,p21+ceil((p12-p21)/2));
        test_lines = B(128:256,128:256);
        test_avg_H  = sum(test_lines,2)/128;
        test_avg_V  = sum(test_lines,1)/128;

        %%%%%Taking slices of the Signal Decay %%%

        Brain = test_avg_V(loc:ceil(loc+5.5/(10*dl)));
        l_Brain = length(Brain);
        new_dim = ceil(l_Brain/n_slices);

        new_Brain = padarray(Brain,[0 new_dim*n_slices-l_Brain],0,'post'); 
        l_Brain = length(new_Brain);
        pulses = zeros(l_Brain,n_slices);
        sig = reshape(new_Brain, [new_dim n_slices]);
        slices = (sig(ceil(length(sig)/2),:));  % Taking mid-point of each rectangular pulse.
        slices = (slices);
        for i = 1:n_slices
            pulses((i-1)*l_Brain/(n_slices)+1:l_Brain/(n_slices)*i,i) =  slices(i);
            fft_pulses(:,i)=fftshift(fft(pulses(:,i)));  % moving the zero-frequency component to the center of the array
            Nf=length(fft_pulses(:,i));         %to take the frquecny axis of the hoarmonics.
            n=-(Nf-1)/2:(Nf-1)/2;  %divide the frequency compone
            f(:,i)=sqrt(fft_pulses(:,i).*conj(fft_pulses(:,i))); % to take the amplitude of each hoarmony.
            figure;
            plot(f(:,i));
            title('Fourier Transform of the pulses');
            xlabel('frequency ');
            ylabel('Amplitude');

        end

        pulses = padarray(pulses,loc,0,'pre');
        pulses = padarray(pulses,100,0,'post');
        %Plotting figures
        figure;
        bar(pulses,5,'hist');
        hold on
        plot(test_avg_V);

% figure % plot(pulses) % hold on % plot(flipud(test_avg_V)); figure; plot(f); figure; plot(test_lines') title('test lines') figure; plot(test_avg_V); title('Magnetic Field Decay Ratio'); xlabel('Distance on y-axis'); ylabel('B1');

        figure

        surf(x,y,B);
        view(0,90);
        colorbar;
        xlabel('x');
        ylabel('y');
        title('B1 Profile');
    end

end

Regards

Dhafer

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/29922-why-your-question-is-not-urgent-or-an-emergency

Answer 1

[Youssef Khmou]

hi,

delete this portion :

    L = input('Please enter the grid length and size [l s]: ');
    N = L(2);   l = L(1);

And replace it with :

    N = input('Please enter the grid length :');
    l=input('Enter the grid size');

[Dhafer]

Hi Youssef

Thanks for helping me, but still create error (new error).

Regards

Dhafer

[Walter Roberson]

What is the new error? On which line?

[Youssef Khmou]

hi Dhafer , the new error is not technical , but its about the conception of the code or the entered values, i think the error is

1) Matrix dimensions must agree or

2) Index exceeds