 <p>In general, thrust operations dispatched on the "host" are not run in parallel. They use a single host thread.</p> <p>If you want to run thrust operations in parallel on the CPU (using multiple CPU threads) then the recommended practice would be to use the thrust OpenMP backend.</p> <p>A fully worked example is <a href="https://github.com/thrust/thrust/wiki/Direct-System-Access" rel="nofollow noreferrer">here</a>.</p> <p>Another worked example is <a href="http://stackoverflow.com/questions/25311538/thrust-equivalent-of-open-mp-code">here</a>.</p>