message: Add ptr constructor to ek::Tensor
diff: @@ -145,6 +145,14 @@ struct Tensor
  size, data.size());
  }
  + Tensor(const void *ptr, size_t ndim, const size_t *shape)
  + : m_shape(shape, shape + ndim) {
  + size_t size = 1;
  + for (size_t i = 0; i < ndim; ++i)
  + size *= shape[i];
  + m_array = load<Array>(ptr, size);
  + }
  +
  operator Array() const { return m_array; }
  Tensor add_(const Tensor &b) const {
  