Struct DeviceGroup 

pub struct DeviceGroup { /* private fields */ }

A set of devices participating in single-process collectives.

The first device is the leader: reductions land there, because a reduced value has to live somewhere and the caller needs to know where without asking.

Implementations

impl DeviceGroup

pub fn new(devices: Vec<Device>) -> Result<Self>

Build a group over devices. The first is the leader.

Returns Err for an empty list rather than panicking — a group with no devices has no leader, so every collective on it would be undefined.

pub fn size(&self) -> usize

Number of devices in the group.

pub fn leader(&self) -> &Device

The leader device — where reductions land.

pub fn devices(&self) -> &[Device]

The devices in this group, in rank order.

pub fn all_reduce(&self, shards: &[Tensor], op: ReduceOp) -> Result<Tensor>

Reduce shards element-wise onto the leader device.

Shard i is taken to live on device i — the group’s device list is the residency map, so shards.len() must not exceed size. Each shard is brought to the leader (staging through CPU when it must cross vendors) and folded with op.

pub fn all_gather(&self, shards: &[Tensor], dim: usize) -> Result<Tensor>

Concatenate shards along dim onto the leader device.

The gather counterpart of all_reduce: where reduce combines values element-wise, this preserves every shard’s contribution.

pub fn realize_f32(&self, t: &Tensor) -> Result<Vec<f32>>

Realize t as f32, seeding a device handle for every device in the group.

A plain Tensor::realize_f32 seeds only the primary device, so a graph whose nodes span several backends cannot be executed through it — the non-primary backends have no handle to allocate against. This routes through pipelined_bridge::realize_one_as_multi_device with the leader as primary and the remaining group devices as extras, which is the entry the existing live multi-vendor tests use.

Callers should not have to know that: the group already owns the device list, so it is the natural place for the seeding to live.

Trait Implementations

impl Clone for DeviceGroup

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DeviceGroup

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.