code: function lnprior(theta) {
    var m = theta[0], b = theta[1], t = theta[2];
    if (0.0 < m && m < 1.0 && 0.0 < b && b < 10.0 && 0.0 < t && t < 100.0) {
      return 0.0;
    }
    return -Infinity;
  }
docs: uniform log-prior for m, b, t