local_vars = {
'ns0': lambda sdei: sympy.sqrt(sdei.S.d0 * sdei.S.dt * 2.0 / sdei.S.gam1),
'ns1': lambda sdei: sympy.sqrt(sdei.S.d0 * sdei.S.dt * 2.0 / sdei.S.gam2),
}
const_pars = {
'phi0': lambda sdei: numpy.random.uniform(0.0, 2.0 * numpy.pi, sdei.num_threads)
}
code = """
dx0 = (is * sinf(x0 - x1) + f1 + amp * cosf(t + phi0)) / gam1;
dx1 = (-is * sinf(x0 - x1) + f2) / gam2;
"""
ns_map = {0: ['ns0', 0], 1: [0, 'ns1']}
period_map = {0: sde.PeriodInfo(period=2.0 * math.pi, freq=1.0)}
sdei = sde.SDE(code, sim_params, num_vars=2, num_noises=2, noise_map=ns_map, period_map=period_map,
local_vars=local_vars, const_pars=const_pars)
output = {'path': {
'main': [sde.OutputDecl(func=sde.avg_moments, vars=[0, 1])],
},
'summary': {
'main': [sde.OutputDecl(func=sde.drift_velocity, vars=[0, 1])],
}
}
sdei.prepare(sde.SRK2, init_vector)
sdei.simulate(output, block_size=128)
'a2': 'AC drive amplitude for the 2nd particle',
'omega': 'AC drive frequency'
}
local_vars = {
'ns0': lambda sdei: sympy.sqrt(sdei.S.d0 * sdei.S.dt),
}
code = """
dx0 = i1 - sinf(x0) + alpha * (i2 - sinf(x1)) + (a1 + alpha * a2) * cosf(omega * t + phi0);
dx1 = i2 - sinf(x1) + alpha * (i1 - sinf(x0)) + (alpha * a1 + a2) * cosf(omega * t + phi0);
"""
ns_map = {0: ['ns0', 0], 1: [0, 'ns0']}
period_map = {
0: sde.PeriodInfo(period=2.0 * math.pi, freq=1),
1: sde.PeriodInfo(period=2.0 * math.pi, freq=1)
}
sdei = sde.SDE(code,
sim_params,
num_vars=2,
num_noises=2,
const_pars=const_pars,
noise_map=ns_map,
period_map=period_map,
local_vars=local_vars)
output = {
'path': {
'main': [sde.OutputDecl(func=sde.avg_moments, vars=[0, 1])],
'gamma_': 'damping constant',
'psd': 'potential strenght',
'd0': 'noise strength'
}
local_vars = {
'ns': lambda sdei: sympy.sqrt(sdei.S.d0 * sdei.S.dt * 2.0 * sdei.S.gamma_)
}
code = """
dx0 = x1;
dx1 = -psd * sinf(x0) - gamma_ * x1 + force;
"""
noise_map = {1: ['ns']}
period_map = {0: sde.PeriodInfo(period=2.0 * numpy.pi, freq=1)}
sde_ = sde.SDE(code,
params,
num_vars=2,
num_noises=1,
noise_map=noise_map,
period_map=period_map,
local_vars=local_vars)
output = {
'summary': {
'main': [sde.OutputDecl(func=sde.diffusion_coefficient, vars=[0])],
},
'path': {
'main': [