docs: function(q, lowerTail, logp) {
              var ind, ret;
  
              logp = logp === true;
              lowerTail = lowerTail !== false;
  
              if (utils.hasNaN(q)) { return NaN; }
              if (q < xs[0]) {
                 ret = lowerTail ? 0 : 1;
              } else if (q >= xs[xs.length - 1]) {
                 ret = lowerTail ? 1 : 0;
              } else {
                 ind = binSearch(xs, function(y) { return y <= q; });
                 ret = lowerTail ? cumsLeft[ind] : cumsRight[ind];
              }
              ret = Math.min(ret, 1);
              return logp ? Math.log(ret) : ret;
           }