def intmM(L,m0,m1,M0,M1,w=0,EI=1.):
    return (L/24.)*(m0*(w*L*L + 8.*M0 + 4.*M1) + m1*(w*L*L + 4.*M0 + 8.*M1))/EI

# units are kN and m
EI = 90000 # kN m^2
intmM( L=2, m0=0, m1=3, M0=0, M1=-30, EI=EI) + \
intmM( L=3, m0=3, m1=0, M0=-30, M1=0, EI=EI ) + \
intmM( L=2, m0=0, m1=-2, M0=0, M1=-20, EI=EI ) + \
intmM( L=2, m0=-2, m1=0, M0=-20, M1=0, EI=EI )