def index_function(n):
index = Function.index(nargs=(n, ), shape=(), integer=True)
k = Symbol.k(integer=True)
def eval(x, *indices):
(j, ), *_ = indices
return LAMBDA[k:n](KroneckerDelta(x[k], j)) @ LAMBDA[k:n](k)
index.eval = eval
return index
k = Symbol.k(integer=True)
index = Function.index(nargs=(n, ),
shape=(),
integer=True,
eval=lambda x, *indices: LAMBDA[k:n]
(KroneckerDelta(x[k], indices[0][0])) @ LAMBDA[k:n]
(k))
return index
