def test_transfer_cuda_gpu():
    import theano.sandbox.cuda as cuda_ndarray
    if cuda_ndarray.cuda_available is False:
        raise SkipTest("Can't test interaction with cuda if cuda not present")
    g = GpuArrayType(dtype='float32', broadcastable=(False, False))('g')
    c = cuda_ndarray.CudaNdarrayType((False, False))('c')

    av = theano._asarray(rng.rand(5, 4), dtype='float32')
    gv = gpuarray.array(av)
    cv = cuda_ndarray.CudaNdarray(av)
    gvs = gv[:, ::-2]
    cvs = cv[:, ::-2]

    f = theano.function([c], gpu_from_cuda(c))
    fv = f(cv)
    assert GpuArrayType.values_eq_approx(fv, gv)

    fvs = f(cvs)
    assert GpuArrayType.values_eq_approx(fvs, gvs)

    f = theano.function([g], cuda_from_gpu(g))
    fv = f(gv)
    assert cuda_ndarray.CudaNdarrayType.values_eq_approx(fv, cv)

    fvs = f(gvs)
    assert cuda_ndarray.CudaNdarrayType.values_eq_approx(fvs, cvs)

def rand_gpuarray(*shape, **kwargs):
    r = rng.rand(*shape) * 2 - 1
    dtype = kwargs.pop('dtype', theano.config.floatX)
    cls = kwargs.pop('cls', None)
    if len(kwargs) != 0:
        raise TypeError('Unexpected argument %s', kwargs.keys()[0])
    return gpuarray.array(r, dtype=dtype, cls=cls)

def test_transfer_cpu_gpu():
    a = T.fmatrix('a')
    g = GpuArrayType(dtype='float32', broadcastable=(False, False))('g')

    av = numpy.asarray(rng.rand(5, 4), dtype='float32')
    gv = gpuarray.array(av)

    f = theano.function([a], gpu_from_host(a))
    fv = f(av)
    assert GpuArrayType.values_eq(fv, gv)

    f = theano.function([g], host_from_gpu(g))
    fv = f(gv)
    assert numpy.all(fv == av)

def test_transfer_strided():
    # This is just to ensure that it works in theano
    # compyte has a much more comprehensive suit of tests to ensure correctness
    a = T.fmatrix('a')
    g = GpuArrayType(dtype='float32', broadcastable=(False, False))('g')

    av = numpy.asarray(rng.rand(5, 8), dtype='float32')
    gv = gpuarray.array(av)

    av = av[:,::2]
    gv = gv[:,::2]

    f = theano.function([a], gpu_from_host(a))
    fv = f(av)
    assert GpuArrayType.values_eq(fv, gv)

    f = theano.function([g], host_from_gpu(g))
    fv = f(gv)
    assert numpy.all(fv == av)