How to sum a series of functions generated from data

Question

Jonathan Davidson 2019-4-25

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/458574-how-to-sum-a-series-of-functions-generated-from-data

回答： Mark Sherstan 2019-4-25

采纳的回答： Mark Sherstan

在 MATLAB Online 中打开

I have some 2D XRD data in array form(details don't matter).

Essentially I have a list of peak intensities, and miller indices h,k

I wish to plot the paterson function which in this case is

Where u and v are coordinates on the unit mesh.

Converting u,v to x,y and plotting them is straightforward. But I can't seem to get a handle on how to do the summation.

My initial attempt was to define a Paterson function for each individual reflection in my dataset, and then sum them together.

However it seems Matlab isn't happy having u and v defined in the way I have done.

clear all
%define unit mesh
a = 20.46;
b = 9.99;
gamma = 34.12;
%create array
x = [-2*a:1:2*a];
y = [-2*a:1:2*a];
%define u and v
u = x - y*cot(gamma*pi/180);
v = y*csc(gamma*pi/180);
%import data and create Paterson for each reflection
data = csvread('mydata.csv');
for N =1 : size(data,1);
    peakn = data(N,1);
    F = data(N,2);
    h = data(N,3);
    k = data(N,4);
    Paterson(N,u,v) = F^2*cos(2*pi*(h*u+k*v));
end

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Answer 1

Mark Sherstan 2019-4-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/458574-how-to-sum-a-series-of-functions-generated-from-data#answer_372309

在 MATLAB Online 中打开

The variable Paterson requires intergers as indices not doubles hence the error. Consider changing that last section as follows:

%import data and create Paterson for each reflection
data = csvread('mydata.csv');
for N =1 : size(data,1);
    peakn = data(N,1);
    F = data(N,2);
    h = data(N,3);
    k = data(N,4);
    Paterson(N,:) = [u v F^2*cos(2*pi*(h*u+k*v))];
end