Error: Unable to perform assignment because left and right sides have a different number of elements

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Jacob Pesquera 2019-10-2

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https://ww2.mathworks.cn/matlabcentral/answers/483333-error-unable-to-perform-assignment-because-left-and-right-sides-have-a-different-number-of-elements

评论： Walter Roberson 2019-10-3

I'm trying to plot a displacement vs. time graph for a simple harmonic oscillator showing different initial displacements to show the behavior of various amplitudes but my code keeps giving me the same error message: Error: Unable to perform assignment because left and right sides have a different number of elements and it specifies that the error is in line (23) but I don't know why it's giving me this error message? Here's my code:

12- N = 2500; %Discretizes time
13- delta_t = 0.04; %Time step in seconds (s)
14- v = zeros(N,1); %Initializes velocity
15- x = zeros(N,1); %Initializes displacement
16- t = zeros(N,1); %Initializes time
17- k = 1; %Spring constant for the mass-spring system
18- a = 1; %Exponential term that determines harmonicity or anharmonicity
20- %Define variables and initialize
22- delta_x_i = [2,5,10]; %Initial displacement vector in meters (m)
23- x(1) = delta_x_i; %First iteration for initial displacement
24- v_0 = 0; %Initial velocity in meters per second (m/s)
25- v(1) = [v_0,v_0,v_0]; %First iteration for velocity
26- t_0 = 0; %Initial time in seconds (s)
27- t(1) = t_0; %First iteration of time
29- for i=1:N-1 %A for-loop over all the timesteps
        v(i+1) = v(i)-k*x(i)^a*delta_t;
        x(i+1) = x(i)+v(i+1)*delta_t;
        t(i+1) = t(i)+delta_t;
end

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Answer 1

Walter Roberson 2019-10-2

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/483333-error-unable-to-perform-assignment-because-left-and-right-sides-have-a-different-number-of-elements#answer_394545

在 MATLAB Online 中打开

delta_x_i = [2,5,10]

That is a vector of length 3

x(1) = delta_x_i

The left side names a scalar location that can hold only one value. The right side is a vector of length 3.

Hint:

x(1,:) = delta_x_i;

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Jacob Pesquera 2019-10-3

It's giving me the same error message even after including the colon: Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-3.