Continuum Analytics: Documentation

# GPU Reduction

Writing a reduction algorithm for CUDA GPU can be tricky. Numba provides a `@reduce` decorator for converting simple binary operation into a reduction kernel.

## `@reduce`

Example:

    import numpy
    from numba import cuda

    @cuda.reduce
    def sum_reduce(a, b):
        return a + b

    A = (numpy.arange(1234, dtype=numpy.float64)) + 1
    expect = A.sum()      # numpy sum reduction
    got = sum_reduce(A)   # cuda sum reduction
    assert expect == got

User can also use a lambda function:

    sum_reduce = cuda.reduce(lambda a, b: a + b)

## class Reduce

The `reduce` decorator creates an instance of the `Reduce` class. (Currently, `reduce` is an alias to `Reduce`, but this behavior is not guaranteed.)

class `numba.cuda.``Reduce`(binop)