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MSc2-Project-Chaos/Source/poincare_sections.py
Yael-II 6b06be4a6b update
2025-01-19 17:31:02 +01:00

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Python

#!/usr/bin/env python
"""
Poincaré Sections
Computes the Poincaré Sections
@ Author: Moussouni, Yaël (MSc student) & Bhat, Junaid Ramzan (MSc student)
@ Institution: Université de Strasbourg, CNRS, Observatoire astronomique
de Strasbourg, UMR 7550, F-67000 Strasbourg, France
@ Date: 2024-11-29
"""
import numpy as np
def pcs_find(pos_x, pos_y, vel_x, vel_y):
"""Find Poincaré sections (PCS; x = 0)
@ params:
- pos_x: position along the x axis
- pos_y: position along the y axis
- pos_x: velocity along the x axis
- pos_y: velocity along the y axis
@ returns: (tuple)
- pcs_pos_y: position of the points in the PCS along the y axis
- pcs_vel_y: velocity of the points in the PCS along the y axis
"""
if np.ndim(pos_x) == 1:
pos_x = np.array([pos_x])
pos_y = np.array([pos_y])
vel_x = np.array([vel_x])
vel_y = np.array([vel_y])
pcs_pos_y = []
pcs_vel_y = []
for j in range(len(pos_x[0])): # for each particle
i = 0
x = pos_x[:,j]
y = pos_y[:,j]
u = vel_x[:,j]
v = vel_y[:,j]
while i < len(x) - 1:
if x[i] * x[i+1] < 0:
y0 = y[i] \
+ (y[i+1] - y[i])/(x[i+1] - x[i]) \
* (0 - x[i])
v0 = v[i] \
+ (v[i+1] - v[i])/(x[i+1] - x[i])\
* (0 - x[i])
pcs_pos_y.append(y0)
pcs_vel_y.append(v0)
i += 1
return pcs_pos_y, pcs_vel_y
def pcs_find_legacy(pos_x, pos_y, vel_x, vel_y):
"""DEPRECIATED - DO NOT USE
Depreciated legacy function that should not be used
"""
if np.ndim(pos_x) == 1:
pos_x = np.array([pos_x])
pos_y = np.array([pos_y])
vel_x = np.array([vel_x])
vel_y = np.array([vel_y])
pcs_pos_y = []
pcs_vel_y = []
for j in range(len(pos_x)): # for each particle
i = 0
x = pos_x[j]
y = pos_y[j]
u = vel_x[j]
v = vel_y[j]
while i < len(x) - 1:
if x[i] * x[i+1] < 0:
y0 = y[i] \
+ (y[i+1] - y[i])/(x[i+1] - x[i]) \
* (0 - x[i])
v0 = v[i] \
+ (v[i+1] - v[i])/(x[i+1] - x[i])\
* (0 - x[i])
pcs_pos_y.append(y0)
pcs_vel_y.append(v0)
i += 1
return pcs_pos_y, pcs_vel_y