def transform(x,a,b):
    """Transforms points from the interval [-1,1] to the interval [a,b].
    
    Parameters
    ----------
    x : numpy array
        The points to be tranformed.
    a : float or numpy array
        The lower bound on the interval. Float if one-dimensional, numpy array if multi-dimensional
    b : float or numpy array
        The upper bound on the interval. Float if one-dimensional, numpy array if multi-dimensional
    
    Returns
    -------
    transform : numpy array
        The transformed points.
    """
    return ((b-a)*x+(b+a))/2