Returns information about effect of constraints on population.

        :param primarylist:
           List of constraint names that you want specific information on
           (i.e., not blended within "multiple constraints".)

        :return:
           ``dict`` of what percentage of population is ruled out by
           each  constraint, including a "multiple constraints" entry.

def constraint_stats(self,primarylist=None):
        """Returns information about effect of constraints on population.

        :param primarylist:
           List of constraint names that you want specific information on
           (i.e., not blended within "multiple constraints".)

        :return:
           ``dict`` of what percentage of population is ruled out by
           each  constraint, including a "multiple constraints" entry.
        """
        if primarylist is None:
            primarylist = []
        n = len(self.stars)
        primaryOK = np.ones(n).astype(bool)
        tot_reject = np.zeros(n)

        for name in self.constraints:
            if name in self.selectfrac_skip:
                continue
            c = self.constraints[name]
            if name in primarylist:
                primaryOK &= c.ok
            tot_reject += ~c.ok
        primary_rejected = ~primaryOK
        secondary_rejected = tot_reject - primary_rejected
        lone_reject = {}
        for name in self.constraints:
            if name in primarylist or name in self.selectfrac_skip:
                continue
            c = self.constraints[name]
            lone_reject[name] = ((secondary_rejected==1) & (~primary_rejected) & (~c.ok)).sum()/float(n)
        mult_rejected = (secondary_rejected > 1) & (~primary_rejected)
        not_rejected = ~(tot_reject.astype(bool))
        primary_reject_pct = primary_rejected.sum()/float(n)
        mult_reject_pct = mult_rejected.sum()/float(n)
        not_reject_pct = not_rejected.sum()/float(n)
        tot = 0

        results = {}
        results['pri'] = primary_reject_pct
        tot += primary_reject_pct
        for name in lone_reject:
            results[name] = lone_reject[name]
            tot += lone_reject[name]
        results['multiple constraints'] = mult_reject_pct
        tot += mult_reject_pct
        results['remaining'] = not_reject_pct
        tot += not_reject_pct

        if tot != 1:
            logging.warning('total adds up to: %.2f (%s)' % (tot,self.model))

        return results