m.scansum(seq,threshold = -1000) -- Sum of scores over every window in the sequence.  Returns
                                            total, number of matches above threshold, average score, sum of exp(score)

def scansum(self,seq,threshold = -1000):
        """
        m.scansum(seq,threshold = -1000) -- Sum of scores over every window in the sequence.  Returns
                                            total, number of matches above threshold, average score, sum of exp(score)
        """
        ll = self.ll
        sum = 0
        width        = self.width
        width_r      = range(width)
        width_rcr    = range(width-1,-1,-1)
        width_ranges = zip(width_r,width_rcr)
        seqcomp      = seq.translate(revcompTBL)

        total = 0
        hits  = 0
        etotal= 0
        for offset in range(len(seq)-width+1):
            total_f = 0
            total_r = 0
            for i,ir in width_ranges:
                pos = offset+i
                total_f = total_f + ll[i][    seq[pos]]
                total_r = total_r + ll[i][seqcomp[pos]]
            total_max = max(total_f,total_r)
            if total_max >= threshold:
                total = total + total_max
                etotal = etotal + math.exp(total_max)
                hits  = hits + 1
            if not hits:
                ave = 0
            else:
                ave = float(total)/float(hits)
        return(total,hits,ave,math.log(etotal))