 Titan is available for any scientific purpose; access depends on the importance of the project and its potential to exploit the hybrid architecture. Any selected code must also be executable on other supercomputers to avoid sole dependence on Titan. Six vanguard codes were the first selected. They dealt mostly with molecular scale physics or climate models, while 25 others queued behind them. The inclusion of GPUs compelled authors to alter their codes. The modifications typically increased the degree of parallelism, given that GPUs offer many more simultaneous threads than CPUs. The changes often yield greater performance even on CPU-only machines.
