Sub-functions

A @qd.kernel can call other functions, as long as those functions are annotated with @qd.func.

qd.func

@qd.func is the standard annotation for a function that can be called from a kernel. @qd.func functions can also call other @qd.func functions.

@qd.func is inlined into the calling kernel at compile time. This means:

• There is no function call overhead

• The compiler can optimize across the call boundary

• Recursive calls are not supported

@qd.func
def add(a: qd.i32, b: qd.i32) -> qd.i32:
    return a + b

@qd.kernel
def compute(a: qd.Template) -> None:
    for i in range(10):
        a[i] = add(i, 1)

Passing fields and ndarrays

Fields and ndarrays can be passed to @qd.func functions:

@qd.func
def increment(arr: qd.Template, idx: qd.i32) -> None:
    arr[idx] += 1

@qd.kernel
def compute(a: qd.Template) -> None:
    for i in range(10):
        increment(a, i)