JITCompiler¶

Overview¶

template <class Real, std::size_t N = 1> class JITCompiler;

JITCompiler is a tape-like recorder/executor for JIT-enabled builds. It:

• records computations into a JITGraph
• compiles the graph using a pluggable JITBackend
• provides forward execution and adjoint propagation

Typical usage¶

using AD = xad::AReal<double, 1>;

xad::JITCompiler<double, 1> jit;

AD x = 2.0;
AD y = 3.0;

jit.registerInput(x);
jit.registerInput(y);

jit.newRecording();
AD z = x * y + x;
jit.registerOutput(z);

jit.compile();

double out = 0.0;
jit.forward(&out);

Recording control (TLS)¶

JITCompiler mirrors the tape pattern: a thread-local “active” compiler can be set, so that XAD expression construction/assignment can record into the active JIT compiler when no tape is active.

isActive¶

bool isActive() const

Checks whether this instance is the active compiler for the current thread.

getActive¶

static JITCompiler* getActive()

Returns the active compiler for the current thread, or nullptr if none is active.

activate / deactivate / deactivateAll¶

void activate(), void deactivate(), static void deactivateAll()

Manage the thread-local active compiler pointer.

Graph and backend¶

getGraph¶

JITGraph& getGraph()

Access the recorded graph (mainly for backends and debugging).

setBackend¶

void setBackend(std::unique_ptr<JITBackend> backend)

Replaces the execution backend (requires recompilation of the current graph).

compile¶

void compile()

Compiles the currently recorded graph with the current backend.

Inputs/outputs¶

registerInput / registerInputs¶

Registers independent variables as graph inputs.

registerOutput / registerOutputs¶

Registers dependent variables as graph outputs.

newRecording¶

void newRecording()

Starts a new recording using the existing registered inputs.

Execution¶

forward¶

void forward(double* outputs)

Executes the forward pass and fills the output array.

computeAdjoints¶

void computeAdjoints()

Computes adjoints for the currently recorded graph (after seeding output derivatives).