Sanity-check the arguments for :func:`fgivenx.drivers.compute_samples`.

    Parameters
    ----------
    f, x, samples, weights:
        see arguments for :func:`fgivenx.drivers.compute_samples`

def _check_args(logZ, f, x, samples, weights):
    """ Sanity-check the arguments for :func:`fgivenx.drivers.compute_samples`.

    Parameters
    ----------
    f, x, samples, weights:
        see arguments for :func:`fgivenx.drivers.compute_samples`
    """
    # convert to arrays
    if logZ is None:
        logZ = [0]
        f = [f]
        samples = [samples]
        weights = [weights]

    # logZ
    logZ = numpy.array(logZ, dtype='double')
    if len(logZ.shape) is not 1:
        raise ValueError("logZ should be a 1D array")

    # x
    x = numpy.array(x, dtype='double')
    if len(x.shape) is not 1:
        raise ValueError("x should be a 1D array")

    # f
    if len(logZ) != len(f):
        raise ValueError("len(logZ) = %i != len(f)= %i"
                         % (len(logZ), len(f)))
    for func in f:
        if not callable(func):
            raise ValueError("first argument f must be function"
                             "(or list of functions) of two variables")

    # samples
    if len(logZ) != len(samples):
        raise ValueError("len(logZ) = %i != len(samples)= %i"
                         % (len(logZ), len(samples)))
    samples = [numpy.array(s, dtype='double') for s in samples]
    for s in samples:
        if len(s.shape) is not 2:
            raise ValueError("each set of samples should be a 2D array")

    # weights
    if len(logZ) != len(weights):
        raise ValueError("len(logZ) = %i != len(weights)= %i"
                         % (len(logZ), len(weights)))
    weights = [numpy.array(w, dtype='double') if w is not None
               else numpy.ones(len(s), dtype='double')
               for w, s in zip(weights, samples)]

    for w, s in zip(weights, samples):
        if len(w.shape) is not 1:
            raise ValueError("each set of weights should be a 1D array")
        if len(w) != len(s):
            raise ValueError("len(w) = %i != len(s) = %i" % (len(s), len(w)))

    return logZ, f, x, samples, weights