contiguous

Possible Duplicate: Are std::vector elements guaranteed to be contiguous? I have come across a technique in which people use a vector in C++ to receive or send data for MPI operations as it is said to store elements contiguously in memory. However, I remain skeptical of whether this approach would remain robust for a vector of any size, especially when the vector grows to a certain size, where this assumption could break down. Below is an example of what I am talking about : MPI_Recv( &partials[0] , partials.size() , mpi_partial , 0, DALG_ELIMINATE_REQ_MSG ,MPI_COMM_WORLD , &status ); Yes, C++

I was going through this example of a LSTM language model on github (link) . What it does in general is pretty clear to me. But I'm still struggling to understand what calling contiguous() does, which occurs several times in the code. For example in line 74/75 of the code input and target sequences of the LSTM are created. Data (stored in ids ) is 2-dimensional where first dimension is the batch size. for i in range(0, ids.size(1) - seq_length, seq_length): # Get batch inputs and targets inputs = Variable(ids[:, i:i+seq_length]) targets = Variable(ids[:, (i+1):(i+1)+seq_length].contiguous())

The specialisation of std::vector<bool> , as specified in C++11 23.3.7/1, doesn't declare a data member (e.g. mentioned here and here ). The question is: Why does a std::vector have no .data()? This is the very same question as why is a vector of bools not stored contiguously in memory. What are the benefits in not doing so? Why can a pointer to an array of bools not be returned? gsamaras Why does a std::vector have no .data()? Because an std::vector<bool> stores multiple values in 1 byte. Think about it like a compressed storage system, where every boolean value needs 1 bit. So, instead of