def eigs_s(infile="", dir_path='.'):
    """
    Converts eigenparamters format data to s format

    Parameters
    ___________________
    Input:
        file : input file name with eigenvalues (tau) and eigenvectors (V) with  format:
            tau_1 V1_dec V1_inc tau_2 V2_dec V2_inc tau_3 V3_dec V3_inc
    Output
         the six tensor elements as a nested array
          [[x11,x22,x33,x12,x23,x13],....]

    """
    file = os.path.join(dir_path, infile)
    eigs_data = np.loadtxt(file)
    Ss = []
    for ind in range(eigs_data.shape[0]):
        tau, Vdirs = [], []
        for k in range(0, 9, 3):
            tau.append(eigs_data[ind][k])
            Vdirs.append([eigs_data[ind][k+1], eigs_data[ind][k+2]])
        s = list(pmag.doeigs_s(tau, Vdirs))
        Ss.append(s)
    return Ss
Converts eigenparamters format data to s format

    Parameters
    ___________________
    Input:
        file : input file name with eigenvalues (tau) and eigenvectors (V) with  format:
            tau_1 V1_dec V1_inc tau_2 V2_dec V2_inc tau_3 V3_dec V3_inc
    Output
         the six tensor elements as a nested array
          [[x11,x22,x33,x12,x23,x13],....]