[GitHub] aaronmarkham opened a new issue #12401: cpp_package instructions need clarification and examples need repair

[GitBox <gi...@apache.org>]

aaronmarkham opened a new issue #12401: cpp_package instructions need clarification and examples need repair
URL: https://github.com/apache/incubator-mxnet/issues/12401
 
 
   I tried following the [instructions for building c++ examples](https://github.com/apache/incubator-mxnet/tree/master/cpp-package#building-c-examples-in-examples-folder).
   
   The resulting binaries don't work out of the box, and after troubleshooting some terminate abruptly, core dump or do nothing.
   
   ```
   ./alexnet: error while loading shared libraries: libmxnet.so: cannot open shared object file: No such file or directory
   ```
   
   I worked on the example C++ for image prediction (#12397) that has its own Makefile that points to libmxnet.so specifically, and was able to get it to run without hunting for the mxnet library. The Makefile for the `cpp-package/example` files does not mention the library at all. Maybe that's a problem? 
   
   The steps in the README could use some clarification. Eventually after trying a bunch of things, I found a reference that led me to try this:
   
   ```
   export LD_LIBRARY_PATH=~/incubator-mxnet/lib
   ```
   
   And some of the examples started working! At least they're finding the library. I can add this line to the instructions if this is what we should recommend that people do after building from source with the cpp package flag turned on.  Is it?
   
   But, then there's also the fact that several the examples core dump:
   
   ```
   ./mlp_gpu
   [21:13:44] src/io/iter_mnist.cc:110: MNISTIter: load 60000 images, shuffle=1, shape=(100,784)
   [21:13:44] src/io/iter_mnist.cc:110: MNISTIter: load 10000 images, shuffle=1, shape=(100,784)
   terminate called after throwing an instance of 'dmlc::Error'
     what():  [21:13:44] ../include/mxnet-cpp/ndarray.hpp:54: Check failed: MXNDArrayCreate(shape.data(), shape.size(), context.GetDeviceType(), context.GetDeviceId(), delay_alloc, &handle) == 0 (-1 vs. 0) 
   ```
   
   ```
   ./inception_bn 
   terminate called after throwing an instance of 'dmlc::Error'
     what():  [21:15:16] ../include/mxnet-cpp/symbol.hpp:219: Check failed: MXSymbolInferShape(GetHandle(), keys.size(), keys.data(), arg_ind_ptr.data(), arg_shape_data.data(), &in_shape_size, &in_shape_ndim, &in_shape_data, &out_shape_size, &out_shape_ndim, &out_shape_data, &aux_shape_size, &aux_shape_ndim, &aux_shape_data, &complete) == 0 (-1 vs. 0) 
   ```
   
   ```
   ./test_score 
   terminate called after throwing an instance of 'std::logic_error'
     what():  basic_string::_M_construct null not valid
   Aborted (core dumped)
   ```
   
   Or do nothing:
   
   ```
   ./test_optimizer 
   ```
   

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