Using Ascent with data on host and device

[benjaminjeliot]

Hi everyone,

Can I use Ascent with data distributed on the host and device -- e.g. GPU? Are there any examples that demonstrate how to achieve this? Or does the data have to be copied to the host before setting up the simulation data with Conduit?

For data that requires processing before passing to Ascent, is there a way to use a callback (or similar) from Ascent when the data is required? For example, to call a function when an Ascent trigger condition is met? Or alternatively pass a get function instead of a pointer when adding data to Conduit?

Many thanks,
Jim

[JustinPrivitera]

We are working on adding device support to Conduit, which will be leveraged in Ascent at a later date. Other developers (@cyrush?) may know if there are currently other, more limited ways of using Ascent with data distributed on host and device.

[cyrush]

@benjaminjeliot You can pass device pointers to Ascent via Conduit trees built using set_external calls. Ascent has checks to see if the data is on the host or on the device and will move as necessary.

So in most cases there is nothing special you need to do to pass device pointers as long as it is valid Conduit Blueprint.

We do not have a specific GPU tutorial / example, but we can help if you have any issues.

[benjaminjeliot]

Thanks for your reply @cyrush . That's really helpful, I'll give it a try.