% contract the d-th dimension of tensor t with the vector v to produce
% a matrix

function a = tcontract(t,v,d)

tdim = tdimensions(t);

adim = [];
for p=1:3,
  if p ~= d,
    adim = [adim tdim(p)];
  end
end

a = zeros(adim);

for s=1:tdim(d),
  a = a + v(s)*tgetmatrix(t,s,d);
end