22 lines
737 B
Matlab
22 lines
737 B
Matlab
function dy=glfdiff_mem(y,t,gam,L0)
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% glfdiff_mem - evaluation of O(h) GL derivatives with short memory principle
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%
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% dy=glfdiff_mem(y,t,gam,L0)
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%
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% y - the samples of the function handle of the original function
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% t - the time vector
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% gam - the fractional order
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% L0 - the memory length
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% dy - the fractional-order derivatives, or integrals if gam<0
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% Copyright (c) Dingyu Xue, Northeastern University, China
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% Last modified 28 March, 2017
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% Last modified 18 May, 2022
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arguments, y(:,1), t(:,1), gam(1,1), L0=length(t); end
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[y,h,n]=fdiffcom(y,t); w=[1,zeros(1,n-1)]; dy(1)=0;
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for j=2:L0+1, w(j)=w(j-1)*(1-(gam+1)/(j-1)); end
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for i=1:n
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L=min([i,L0]); dy(i,1)=w(1:L)*y(i:-1:i-L+1)/h^gam;
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end
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end
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