def test_host_write(self, backend, elems, x, g):
        kernel = """void k(unsigned int *x, unsigned int *g) { *g += *x; }"""
        x.data[:] = 1
        g.data[:] = 0
        op2.par_loop(op2.Kernel(kernel, 'k'), elems,
                     x(op2.READ), g(op2.INC))
        _nelems = elems.size
        assert g.data[0] == _nelems

        x.data[:] = 2
        g.data[:] = 0
        op2.par_loop(op2.Kernel(kernel, 'k'), elems,
                     x(op2.READ), g(op2.INC))
        assert g.data[0] == 2 * _nelems
Increment a global by the values of a Dat.
dataset/ETHPy150Open OP2/PyOP2/test/unit/test_direct_loop.py/TestDirectLoop.test_host_write