Not enough input arguments. And there is an error in "N = length(N_func);"

Question

Joy 2022-1-26

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1637060-not-enough-input-arguments-and-there-is-an-error-in-n-length-n_func

评论： Walter Roberson 2022-1-27

Here is my code in editor:

function [ck , ck_magnitude, ck_phase] = analysis (N_func)
%%this is the analysis function 
%N_func refers to the values for a function in a period 
%ck refers to array of coefficients
%ck_magnitude refers to the arrays of coefficient magnitude
%ck_phase refers to the arrays of coefficient phase
%the goal is to create an array for fourier coefficient by using analysis
%equation
ck=zeros(0);
ck_magnitude=zeros(0);
ck_phase=zeros(0);
N = length(N_func);
for k = (0:N-1)
    n = 0:N-1;
    ck= [ck, (sum(N_func .*exp(-(1j)*2*pi*k*n/N)/N))];
    ck_magnitude=[ck_magnitude, sqrt(real(ck(k+1))^2+img(ck(k+1))^2)];
    ck_phase = [ck_phase, atan(imag(ck(k+1))/real(ck(k+1)))];
    
end
tiledlayout (2,1)
nexttile
plot_func('k' , 'phase(rad)', 0:N-1 , circshift(ck_phase,-1),'phase');
nexttile
plot_func('k', 'magnitude',0:N-1, circshift(ck_magnitude, -1),'magnitude');
end

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Matt J 2022-1-26

You need to post it in a form that we can run as you did, i.e., we need to see how the function was invoked.

Also, we need to see complete copy/pastes of the error messages that you see.

Joy 2022-1-26

the error message is

Not enough input arguments.

Error in lab2 (line 12)

N = length(N_func);

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Answer 1

Walter Roberson 2022-1-26

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1637060-not-enough-input-arguments-and-there-is-an-error-in-n-length-n_func#answer_882625

You cannot run that code just by clicking on the green Run button. You need to go down to the command line and invoke the code passing in a vector of data. (Or you could write a script that gathered the data and passed it to the function, and then you could press the green Run button on that script.)

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Joy 2022-1-27

but N_Func is te value a function. I cannot write it like 1 1 1

Walter Roberson 2022-1-27

在 MATLAB Online 中打开

N_func = YourNFunction(appropriate_input_for_function);
[ck , ck_magnitude, ck_phase] = analysis(N_func);

where YourNFunction is the function that calculates N_func given appropriate parameters.

... If I were to guess about what you are actually trying to do:

dinfo = dir('*.xlsx');
filenames = fullfile( {dinfo.folder}, {dinfo.name});
nfiles = length(filenames);
cks = cell(nfiles,1);
ck_magnitudes = cell(nfiles,1);
ck_phases = cell(nfiles,1);
for K = 1 : nfiles
   thisfile = filenames{K};
   T = readtable(thisfile);
   N_func = T{:,2};   %guessing about which column contains the data to be analyzed
   [cks{K}, ck_magnitudes{K},ck_phases{K}] = analysis(N_func);   
end

But I could easily be wrong. Perhaps instead you have a single signal and you have (somehow) split it into intervals, such as if you did silence detection.

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