astronomy.py 文件源码

def int_imf_dm(m1,m2,m,imf,bywhat='bymass',integral='normal'):
    ''' 
    Integrate IMF between m1 and m2.

    Parameters
    ----------
    m1 : float
        Min mass
    m2 : float
        Max mass
    m : float
        Mass array
    imf : float
        IMF array
    bywhat : string, optional
        'bymass' integrates the mass that goes into stars of
        that mass interval; or 'bynumber' which integrates the number
        of stars in that mass interval.  The default is 'bymass'.
    integrate : string, optional
        'normal' uses sc.integrate.trapz; 'cum' returns cumulative
        trapezoidal integral.  The default is 'normal'.

    '''


    ind_m = (m >= min(m1,m2)) & (m <= max(m1,m2))
    if integral is 'normal':
        int_func = sc.integrate.trapz
    elif integral is 'cum':
        int_func = sc.integrate.cumtrapz
    else:
        print("Error in int_imf_dm: don't know how to integrate")
        return 0

    if bywhat is 'bymass':
        return int_func(m[ind_m]*imf[ind_m],m[ind_m])
    elif bywhat is 'bynumber':
        return int_func(imf[ind_m],m[ind_m])
    else:
        print("Error in int_imf_dm: don't know by what to integrate")
        return 0