Judge an array contains a given value or not.

Accelerated Computing CUDA CUDA Programming and Performance
1

What is the quickest way to judge an array contains a given value or not.I want to set a global flag, once a thread find the value, set the flag is true. But it is time-costuming for other threads to search for once the flag is true. How to skip searching actions from other threads once the flag is true?

Regards,

zlf

2

Generally you can read in one element per thread, use the warp voting function to determine if any thread in the warp contains the value:

float val = d_ptr[ idx ] ;

int valueInThisWarp = __any( val == givenValue );

if( valueInThisWarp  )
d_global_flag[0] = 1;

Now to speed this up you may have few blocks searching through many elements ( many elements per thread), hence there will be fewer active threads after the value has been found.