def METHOD_NAME(operator):
    '''Return a elementwisekernel with the operator being one of
    +, -, /, * as a string.
    '''
    _ker = pycuda.elementwise.ElementwiseKernel(
            'double* out, double* a, const double* b',
            'out[i] = a[i] %s b[0]' %operator
        )
    return _ker