Module conditional 

Conditional graph nodes (cudaGraphConditionalNode, CUDA 12.4+).

Gated behind the graphs-conditional Cargo feature. Even with the feature on, the [GraphActor] runtime probe disables the path on older drivers — IfNodeDescriptor::record returns Unrecoverable("conditional graphs unsupported") if the cuGraphConditionalHandleCreate symbol can’t be resolved.

Public surface:

• ConditionalKind — If or While.
• IfNodeDescriptor / WhileNodeDescriptor — typed descriptors carrying the inner graph that will be replayed when the predicate is non-zero.

Structs

IfNodeDescriptor

Descriptor for an If-style conditional node. The inner graph is out-parameter-allocated by CUDA when the node is created — callers receive its handle back so they can populate it before exec instantiation.

WhileNodeDescriptor

Descriptor for a While-style conditional node.

Enums

ConditionalKind

Kind of conditional node. Matches CU_GRAPH_COND_TYPE_*.

Functions

build_params

Build the raw CUDA_CONDITIONAL_NODE_PARAMS for kind against parent’s context. The returned struct embeds an out-pointer (phGraph_out) that CUDA fills with the inner graph; the actor adds it to the parent via cuGraphAddNode_v2.

driver_supports_conditional

Probe whether the running CUDA driver supports conditional graphs. Returns Ok(true) if cuGraphConditionalHandleCreate is callable (i.e. CUDA ≥ 12.4 with the symbol present); Ok(false) otherwise; Err(GpuError::Unrecoverable) if the loader panics.