def _compute_v1_factor(self, imt):
        """
        Compute and return v1 factor, equation 6, page 77.
        """
        if imt.name == "SA":
            t = imt.period
            if t <= 0.50:
                v1 = 1500.0
            elif t > 0.50 and t <= 1.0:
                v1 = np.exp(8.0 - 0.795 * np.log(t / 0.21))
            elif t > 1.0 and t < 2.0:
                v1 = np.exp(6.76 - 0.297 * np.log(t))
            else:
                v1 = 700.0
        elif imt.name == "PGA":
            v1 = 1500.0
        else:
            # this is for PGV
            v1 = 862.0

        return v1
def _compute_v1_factor ( self , imt ) : if imt . name == "SA" : t = imt . period if t <= 0.50 : v1 = 1500.0 elif t > 0.50 and t <= 1.0 : v1 = np . exp ( 8.0 - 0.795 * np . log ( t / 0.21 ) ) elif t > 1.0 and t < 2.0 : v1 = np . exp ( 6.76 - 0.297 * np . log ( t ) ) else : v1 = 700.0 elif imt . name == "PGA" : v1 = 1500.0 else : v1 = 862.0 return v1
Compute and return v1 factor, equation 6, page 77.