C++/STL: std::transform with given stride?

Question

I have a 1d array containing Nd data, I would like to effectively traverse on it with std::transform or std::for_each.

unigned int nelems;
unsigned int strid         


        

Answer 1

Well, I have decided to use for_each instead of transform any other decisions are welcome:

generator gen(0, 1);
            vector idx(m_nelem);//make an index
            std::generate(idx.begin(), idx.end(),gen);
            std::for_each(idx.begin(), idx.end(), strMover(&pPOS[0],&m_COM[0],stride));

where

template T op_sum (T i, T j) { return i+j; }
template 
class strMover
    {
    T *pP_;
    T *pMove_;
    unsigned int stride_;
    public:
        strMover(T *pP,T *pMove, unsigned int stride):pP_(pP), pMove_(pMove),stride_(stride)
            {}
        void operator() ( const unsigned int ip )
            {
            std::transform(&pP_[ip*stride_], &pP_[ip*stride_]+stride_, 
                pMove_, &pP_[ip*stride_], op_sum);
            }
    };

From first look this is a thread safe solution.