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34 lines
1.1 KiB
34 lines
1.1 KiB
1 year ago
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function [l,Bas] = ComputeSplineBasis(xi,p,Xi)
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if xi>=0.0 && xi<1.0
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l=which_knot(xi,Xi);
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% offset=p-l+1;
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N=zeros(p,length(Xi)-1);
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N(1,l)=1;
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for k=2:(p+1)
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for i=1:(length(Xi)-k)
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% if i>=(1)
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% Bik = (xi-Xi(i))/(Xi(i+k)-Xi(i));
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% N(i,k) = Bik*N(i,k-1);
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% elseif i<=0
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% Bi1k = (xi-Xi(i+1))/(Xi(i+1+k)-Xi(i+1));
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% N(i,k) = (1-Bi1k)*N(i+1,k-1);
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% else
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Bik = (xi-Xi(i))/(Xi(i+k-1)-Xi(i));
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Bi1k = (xi-Xi(i+1))/(Xi(i+1+(k-1))-Xi(i+1));
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if isnan(Bik)||Bik==-Inf || Bik==Inf
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Bik=0;
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end
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if isnan(Bi1k)||Bi1k==-Inf || Bi1k==Inf
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Bi1k=0;
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end
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N(k,i) = (1-Bi1k)*N(k-1,i+1)+Bik*N(k-1,i);
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% end
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end
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end
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% Bas=zeros(1,length(Xi)-p-1)
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Bas=N(end,:);
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else
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l=0;
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Bas=zeros(1,length(Xi)-p-1);
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end
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end
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