C++ API print DLTensor values?

jinfagang · March 23, 2022, 9:00am

How to convenient print DLTensor values?

Like

DLTensor* a;

I have to using ((float*)a->data)[0] any better way to print one value out?

ganler · March 25, 2022, 12:17am

@jinfagang

convert DLTensor to NDArray; https://github.com/apache/tvm/blob/58716081637fdf21bdae44122086f1dbc35f7c35/include/tvm/runtime/ndarray.h#L92
Print NDArray: https://github.com/apache/tvm/blob/8bbb2066860670e67389496f91b81d3d1f9e3170/src/printer/tvmscript_printer.cc#L422

jinfagang · March 25, 2022, 2:18am

thanks. does there any demo to call these api? for instance, I have a tvm::runtime::NDArray a

can I using cout << a to print values?

ganler · March 25, 2022, 3:42am

Maybe no (need to confirm) but you can use NDArrayToTIR<float>(a, std::cout) from here:

github.com

apache/tvm/blob/8bbb2066860670e67389496f91b81d3d1f9e3170/src/printer/tvmscript_printer.cc#L423


    return header;
  }
};


/*!
 * \brief special method to print NDArray in TIR
 * \param arr the NDArray to be printed
 * \param os the output stream where the NDArray will be printed to
 */
template <typename T>
void NDArrayToTIR(::tvm::runtime::NDArray arr, std::ostream& os) {
  int ndim = arr->ndim;
  int tot_dim = 1;
  for (int i = 0; i < ndim; i++) {
    tot_dim *= arr->shape[i];
  }
  T* data_ptr = reinterpret_cast<T*>(arr->data);
  os << "[";
  for (int i = 0; i < tot_dim; i++) {
    os << (i != 0 ? ", " : "") << data_ptr[i];
  }

I note that this is from source file so maybe just copy and paste the implementation to your project.