Alexandre Sirois-Vigneux

It's a different algorithm using an octree to solve the pressure projection instead of a regular grid. You can get more information about this DOP here:

https://www.sidefx.com/docs/houdini/nodes/dop/gasprojectnondivergentadaptive.html [www.sidefx.com]

Currently this algorithm is not implemented in OpenCL and, therefore, cannot run on the GPU. Depending on the simulation and hardware, a powerful GPU running on a regular grid can outperform an adaptive pressure solve on the CPU.

You don't need to unlock the solver to get your GPU going.

As Thomas said, OpenCL is only used for viscosity and pressure projection. One thing that is not obvious at the moment, is that OpenCL is only used for pressure projection if adaptivity is off.

By default, the shelf tools use adaptive pressure projection, which means you have to uncheck "Solve Pressure with Adaptivity" otherwise OpenCL is only used for viscosity. I will add more info to the tooltip so this is properly documented and hopefully more user-friendly

Let us know if this solves your issue.