HDF5-DIAG: Error detected in HDF5 (1.10.1) thread 0:
  #000: H5F.c line 408 in H5Fis_hdf5(): unable open file
    major: File accessibilty
    minor: Not an HDF5 file
  #001: H5Fint.c line 532 in H5F__is_hdf5(): unable to open file
    major: Low-level I/O
    minor: Unable to initialize object
  #002: H5FD.c line 809 in H5FD_open(): open failed
    major: Virtual File Layer
    minor: Unable to initialize object
  #003: H5FDsec2.c line 346 in H5FD_sec2_open(): unable to open file: name = 'mnist_first250_training_4s_and_9s.arm', errno = 2, error message = 'No such file or directory', flags = 0, o_flags = 0
    major: File accessibilty
    minor: Unable to open file

warning: Mat::load(): cannot open file mnist_first250_training_4s_and_9s.arm

error: Mat::submat(): indices out of bounds or incorrectly used
libc++abi.dylib: terminating with uncaught exception of type std::logic_error: Mat::submat(): indices out of bounds or incorrectly used
Abort trap: 6