You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
25 lines
886 B
25 lines
886 B
1 year ago
|
function val = dC_eval_dt2(C,t0)
|
||
|
|
% Given a bernstein polynomial, evaluates its second derivative at t0;
|
||
|
|
% Input parameters
|
||
|
|
% C: This is a bernstein polynomial's control points (aka coefficients)
|
||
|
|
% t0: This is the point at which we wish to split the polynomial
|
||
|
|
% Output parameters
|
||
|
|
% val: row vector of values of the bernstein polynomial defined by C at t0
|
||
|
|
t0=reshape(t0,1,1,length(t0));
|
||
|
|
[d,n] = size(C);
|
||
|
|
val=zeros(length(t0),d);
|
||
|
|
for j=1:d
|
||
|
|
cdiv_mat=zeros(n,n,length(t0));
|
||
|
|
cdiv_mat(1,:,:)=repmat(C(j,:),1,1,length(t0));
|
||
|
|
for i=2:n
|
||
|
|
cdiv_mat(i,:,:)=cdiv_mat(i-1,:,:).*(1-t0) + circshift(cdiv_mat(i-1,:,:),-1,2).*t0;
|
||
|
|
end
|
||
|
|
% cdiv_mat=triu(fliplr(cdiv_mat));
|
||
|
|
if n>2
|
||
|
|
% val(:,j) = (n-1)*(cdiv_mat(end-1,2,:)-cdiv_mat(end-1,1,:));
|
||
|
|
val(:,j) = (n-1)*(n-2)*(cdiv_mat(end-2,3,:)-2*cdiv_mat(end-2,2,:)+cdiv_mat(end-2,1,:));
|
||
|
|
else
|
||
|
|
val=0;
|
||
|
|
end
|
||
|
|
end
|