chx_generic_functions.py 文件源码

def flow_para_function_explicitq( x, beta, relaxation_rate, flow_velocity, baseline=1, qr=1, q_ang=0 ):
    '''Nov 9, 2017 Basically, make q vector to (qr, angle),  relaxation_rate is actually a diffusion rate
    flow_velocity: q.v (q vector dot v vector = q*v*cos(angle) )'''

    Diff_part=    np.exp(-2 * relaxation_rate* qr**2 * x)
    Flow_part =  np.pi**2/(16*x*flow_velocity*qr* np.cos(q_ang) ) *  abs(  erf(  np.sqrt(   4/np.pi * 1j* x * flow_velocity * qr* np.cos(q_ang) ) ) )**2    
    return  beta*Diff_part * Flow_part + baseline