sorting array

[rhaney]

Hello all,

I have gotten a great deal of help from this forum so far - thanks to all who have assisted me. However, I have another question that is likely simple, but I am relatively new, regarding sorting.

Is there a call available in CUB that does simple array sorting? For example, I have an array of floating-point values (e.g. float arr*) that I wish to sort in ascending order, no keys just the actual values themselves, and I would like it to be device-wide if possible.

Thank you for any help/hints.

[Robert Crovella]

Yes

http://nvlabs.github.io/cub/

that is the entry page for the cub documentation

click on "Device-wide primitives" to get started

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[rhaney]

Thank you for the link and information.

[rhaney]

I was successful in completing a simple sort of floating-point array using CUB. Can you tell me if my function below (where the argument array is allocated on Device) is correct - i.e., will it have performance issues down the road if passed arrays of varying length(s)?

void cubSortArray(float *d_array, unsigned int num_items){
    void *d_temp_storage = NULL;
    size_t temp_storage_bytes = 0;
    cub::DeviceRadixSort::SortPairs(d_temp_storage, temp_storage_bytes,
                                    d_array, d_array, d_array, d_array, num_items);


    cudaMalloc(&d_temp_storage, temp_storage_bytes);
   
    // run sorting operation
    cub::DeviceRadixSort::SortPairs(d_temp_storage, temp_storage_bytes,
                                    d_array, d_array, d_array, d_array, num_items);
   
    // free DEVICE memory
    cudaFree(d_temp_storage);
}

Thanks again for all the help.

On Thursday, April 25, 2019 at 12:05:06 PM UTC-4, txbob wrote:

[Robert Crovella]

There is no reason to be using ::SortPairs if you are not doing key-value sorting.  ::SortKeys may be what you want.