input : N tensors (p0, …, pN−1),

N+2(k-1) monotonically increasing

knots (t−k+1, …, tN−1+k−1)

k, and a small value e

output: N-1+k-1 control tensors

(c0, …, cN−1+k−2)

‖ X0 ‖ ← e+1;

while $\text{∑}_j\Vert {\mathbf{\text{X}}}_j\Vert >e$ do

for j=0 to N-1+k-2 do

Xj ← zero matrix ;

for i=0 to N-1 do

Xj ← Xj +

Λcj(pi,S(ti))Nj,k(ti) ;

end

c′j ← Expcj Xj ;

end

c ← c′ ;

end