Structure problem between host/kernel


I have data structures on the host side that looks like this. ( I show the relevant parts ). Why I need to have it like this is a long story but I think I need to keep this structure.

struct Bar {

    double ind[NR_OF_INPUTS - 2];

    int date;

    int time;


struct Week {

	int numBars;

	struct Bar* bars;


struct ThreadWeeksHolder {

	int nr_weeks_per_thread;

	struct Week* week;


On the host side I then have a an array like this “ThreadWeeksHolder kernel_thread_weeks_holder[32];” Which is filled with data that is read from a file. Everything works fine so far. My problem comes when I try to get this data to the kernel and keep the structure layout. I want to be able to use the same structure on the kernel. This turned out to be way much more complicated then I first thought.

My plan was to try to build a structure on the host with the gpu-pointers received from cudaMalloc and then copy them over to the graphic card but I can’t really get it to work. The problem is that the pointers that I receive from cudaMalloc makes no sense on the host side if I try to dereference them so to speak.( which totally makes sense ). So for example if I have a line like this

cudaMalloc((void**)&kernel_thread_weeks_holder[1].week[2].bars, threadWeeksHolder[i].week[j].numBars*sizeof(struct Bar));

Then I have a pointer kernel_thread_weeks_holder[i].week[j].bars that points to the appropriate place in the GPU-memory. But after that I also will need a “relationship” between kernel_thread_weeks_holder[i].week and kernel_thread_weeks_holder[i].week[j].bars so to speak. But on the host things get messed up then for me. Hope you can understand what I mean and what my problem is.

Anyone have any suggestions or hints how I can solve this problem?

Never dereference device pointers on the host. You have the corresponding host pointer in the original structure you are trying to replicate on the device, so use that one.

I believe that some advice i recently gave in another thread also applies here though.

Thanks! I read through the other thread as well. I think I got some ideas now, gonna try out some things tomorrow.