reshape

auto x = tensor!([0, 2, 2])([1, 2, 3, 4]);
auto y = x.reshape!([0, 4]);

assert(y.shape == [1, 4]);
assert(y.value[0, 0] == 1);
assert(y.value[0, 1] == 2);
assert(y.value[0, 2] == 3);
assert(y.value[0, 3] == 4);

assert(x.grads == [[[0, 0], [0, 0]]]);
y.backward();
assert(x.grads == [[[1, 1], [1, 1]]]);

auto x = tensor!([0, 4], UseGradient.no)([1, 2, 3, 4]);
auto y = x.reshape!([1, 2, 2]);

assert(y.shape == [1, 2, 2]);
assert(y.value[0, 0, 0] == 1);
assert(y.value[0, 0, 1] == 2);
assert(y.value[0, 1, 0] == 3);
assert(y.value[0, 1, 1] == 4);

static assert(!canBackward!(typeof(y)));