The "local" cluster supports up to 512 cores, so you can set the cluster size to 64 and it should use the cores. The ga function also has built-in parallel support.
Some other concerns might come up:
- Each parallel worker is essentially another MATLAB session, so you need to have enough RAM to support 64 MATLAB sessions running simultaneously. The mimimum RAM requirement is 4 GB, recommended is 8 GB, and of course if your problem is bigger, you need more. So for supporting those workers you need 256 or 512 GB of RAM, maybe more.
- Disk I/O : if you have 64 processes accessing disk simultaneously doing heavy I/O you can become bottlenecked on read or write. So you may need to look at technologies like RAID to spread the reads and writes over several drives. A single drive might become your bottleneck (especially if it's also doing OS stuff). I only recommend SSDs nowadays.
- OS: Windows has different core limits for different versions. Make sure that you select a version that's allows the cores you have. Note also that it may be beneficial to disable hyperthreading, so you keep all your precessors in a processor group. On Linux this isn't an issue. For heavy math operations, hyperthreading doesn't really do anything for you anyway.
