Backend Planner

The planner is the bridge between a semantic graph and backend capsules.

At this stage it is deliberately small: given an execution config, an operation tag, and a capsule registry, choose an admissible capsule or explain why none is available. Graph-aware layers can recover those operation tags from NN.IR.OpKind, lower adjacent nodes, and eventually produce executable command buffers without changing the contract story.

structure NN.Backend.PlannedKernel : Type

A backend choice for one graph operation or fused operation.

• op : BackendOp
• capsule : KernelCapsule

def NN.Backend.instReprPlannedKernel.repr : PlannedKernel → Nat → Std.Format

@[implicit_reducible]

instance NN.Backend.instReprPlannedKernel : Repr PlannedKernel

structure NN.Backend.ExecutionPlan : Type

A simple execution plan: one selected capsule per requested operation.

• kernels : List PlannedKernel

@[implicit_reducible]

instance NN.Backend.instReprExecutionPlan : Repr ExecutionPlan

def NN.Backend.instReprExecutionPlan.repr : ExecutionPlan → Nat → Std.Format

def NN.Backend.ExecutionPlan.capsuleNames (p : ExecutionPlan) : List String

Names of the selected backend capsules, useful for audits and logs.

def NN.Backend.ExecutionPlan.admissible (cfg : ExecutionConfig) (p : ExecutionPlan) : Bool

Whether every selected capsule is admitted by the config's trust/device/backend policy.

def NN.Backend.orderByPreference (cfg : ExecutionConfig) (capsules : List KernelCapsule) : List KernelCapsule

Put preferred-provider capsules first while preserving the relative order otherwise.

def NN.Backend.planOp (cfg : ExecutionConfig) (registry : List KernelCapsule) (op : BackendOp) : Except String PlannedKernel

Choose a backend capsule for one operation.

def NN.Backend.planOps (cfg : ExecutionConfig) (registry : List KernelCapsule) (ops : List BackendOp) : Except String ExecutionPlan

Choose backend capsules for a sequence of operations.

def NN.Backend.planOpsAvailable (cfg : ExecutionConfig) (availability : Availability) (registry : List KernelCapsule) (ops : List BackendOp) : Except String ExecutionPlan

Choose backend capsules after filtering the registry by machine/build availability.