def prox_soft_plus(X, step, thresh=0):
    """Soft thresholding with projection onto non-negative numbers
    """
    return prox_plus(prox_soft(X, step, thresh=thresh), step)
def prox_soft_plus ( X , step , thresh = 0 ) : return prox_plus ( prox_soft ( X , step , thresh = thresh ) , step )
Soft thresholding with projection onto non-negative numbers