indicator function u0192 1 x y 1 if water occurs nearby and values in the range u2212 u221e lt u03bb 1 lt u221e we call this style u201c double sided u201d indicators u0192 1 x y 1 if water occurs nearby and y river and u0192 2 x y 1 if water occurs nearby and y financial in this case one could allow either u2212 u221e lt u03bb 1 u03bb 2 u2266 u221e or 0 u2266 u03bb 1 u03bb 2 lt u221e this style with two indicators can be referred to as u201c single sided u201d with a gaussian prior it does not matter which style one uses u2014 one can show that by changing u03c3 2 exactly the same results will be achieved with a laplacian double sided exponential one could also use either style with an exponential prior only positive values are allowed so one must use the double sided style so that one can learn that some indicators push towards one sense and some push towards the other u2014 that is rather than having one weight which is positive or negative we have two weights which are positive or zero one of which pushes towards one answer and the other pushing towards the other according to an aspect of the present invention the constraints and learning algorithm can be derived in part by maximizing the log of equation 2 rather than the equation itself this leads to an objective function note that this objective function is convex since it is the sum of two convex functions thus.