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Add get masses/positions/momenta methods and modify frogleap input/output

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This commit is contained in:
Thibault Barnouin
2021-10-22 16:23:08 +02:00
parent e1431ce1b4
commit 3e40f412e6
3 changed files with 26 additions and 8 deletions
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21
lib/integrator.py
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@@ -24,12 +24,16 @@ def dp_dt(m_array, q_array):
dp_array[np.isnan(dp_array)] = 0.
return dp_array
def frogleap(duration, step, m_array, q_array, p_array, display=False):
def frogleap(duration, step, dyn_syst, display=False):
"""
Leapfrog integrator for first order partial differential equations.
iteration : half-step drift -> full-step kick -> half-step drift
"""
N = np.ceil(duration/step).astype(int)
m_array = dyn_syst.get_masses()
q_array = dyn_syst.get_positions()
p_array = dyn_syst.get_momenta()
if display:
d = DynamicUpdate()
d.min_x, d.max_x = -1.5*np.abs(q_array).max(), +1.5*np.abs(q_array).max()
@@ -42,14 +46,17 @@ def frogleap(duration, step, m_array, q_array, p_array, display=False):
# half-step drift
q_array, p_array = q_array + step/2*p_array/m_array , p_array
#print(p_array)
# In center of mass frame
q_cm = np.sum(m_array.reshape((q_array.shape[0],1))*q_array, axis=0)/m_array.sum()
q_array -= q_cm
if display:
# In center of mass frame
q_cm = np.array([0.,0.])#np.sum(m_array.reshape((q_array.shape[0],1))*q_array, axis=0)/m_array.sum()
# display progression
d.on_running(q_array[:,0], q_array[:,1])
d.on_running(q_array[:,0]-q_cm[0], q_array[:,1]-q_cm[1])
time.sleep(0.01)
for i, body in enumerate(dyn_syst.bodylist):
body.q = q_array[i]
body.p = p_array[i]
body.v = body.p/body.m
return q_array, p_array
return dyn_syst