exemple pendule à ressort

This commit is contained in:
Didictateur 2026-02-16 11:33:29 +01:00
parent d2f533dce9
commit 6abe888da4
4 changed files with 249 additions and 62 deletions

58
chute_libre.py Normal file
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@ -0,0 +1,58 @@
import legrandchien as lgc
import matplotlib.pyplot as plt
import matplotlib.animation as animation
g = lgc.Const(10)
m = lgc.Const(1)
x = lgc.Var("x")
y = lgc.Var("y")
T = 0.5 * m * (x.diff() * x.diff() + y.diff() * y.diff())
V = m * g * y
L = T - V
dico = {
"x" : 0,
"d_x" : 1,
"y" : 0,
"d_y" : 1
}
values = L.solve(dico, 10, 0.1)
# Extraire les données pour x et y
times = sorted(values.keys())
positions_x = [values[t]["x"] for t in times]
positions_y = [values[t]["y"] for t in times]
# Créer la figure
fig, ax = plt.subplots(figsize=(8, 8))
ax.set_xlim(min(positions_x) - 5, max(positions_x) + 5)
ax.set_ylim(min(positions_y) - 5, max(positions_y) + 5)
ax.set_xlabel("X (m)")
ax.set_ylabel("Y (m)")
ax.grid(True)
# Point animé
point, = ax.plot([], [], 'ro', markersize=15, label="Particule")
# Trajectoire
line, = ax.plot([], [], 'b-', alpha=0.3, linewidth=2, label="Trajectoire")
# Texte temps
time_text = ax.text(0.02, 0.95, '', transform=ax.transAxes, fontsize=12)
ax.legend()
def animate(frame):
# Point courant
point.set_data([positions_x[frame]], [positions_y[frame]])
# Trajectoire jusqu'au point courant
line.set_data(positions_x[:frame + 1], positions_y[:frame + 1])
# Texte
time_text.set_text(f"t = {times[frame]:.2f}s\nx = {positions_x[frame]:.2f}m, y = {positions_y[frame]:.2f}m")
return point, line, time_text
ani = animation.FuncAnimation(fig, animate, frames=len(times),
interval=50, blit=True, repeat=True)
plt.show()

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@ -1,59 +0,0 @@
import legrandchien as lgc
import matplotlib.pyplot as plt
import matplotlib.animation as animation
if __name__ == "__main__":
g = lgc.Const(10)
m = lgc.Const(1)
x = lgc.Var("x")
y = lgc.Var("y")
T = 0.5 * m * (x.diff() * x.diff() + y.diff() * y.diff())
V = m * g * y
L = T - V
dico = {
"x" : 0,
"d_x" : 1,
"y" : 0,
"d_y" : 1
}
values = L.solve(dico, 10, 0.1)
# Extraire les données pour x et y
times = sorted(values.keys())
positions_x = [values[t]["x"] for t in times]
positions_y = [values[t]["y"] for t in times]
# Créer la figure
fig, ax = plt.subplots(figsize=(8, 8))
ax.set_xlim(min(positions_x) - 5, max(positions_x) + 5)
ax.set_ylim(min(positions_y) - 5, max(positions_y) + 5)
ax.set_xlabel("X (m)")
ax.set_ylabel("Y (m)")
ax.grid(True)
# Point animé
point, = ax.plot([], [], 'ro', markersize=15, label="Particule")
# Trajectoire
line, = ax.plot([], [], 'b-', alpha=0.3, linewidth=2, label="Trajectoire")
# Texte temps
time_text = ax.text(0.02, 0.95, '', transform=ax.transAxes, fontsize=12)
ax.legend()
def animate(frame):
# Point courant
point.set_data([positions_x[frame]], [positions_y[frame]])
# Trajectoire jusqu'au point courant
line.set_data(positions_x[:frame + 1], positions_y[:frame + 1])
# Texte
time_text.set_text(f"t = {times[frame]:.2f}s\nx = {positions_x[frame]:.2f}m, y = {positions_y[frame]:.2f}m")
return point, line, time_text
ani = animation.FuncAnimation(fig, animate, frames=len(times),
interval=50, blit=True, repeat=True)
plt.show()

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@ -1,5 +1,6 @@
from enum import Enum
import numpy as np
from tqdm import tqdm
class Operation(Enum):
VAR = 1
@ -363,6 +364,8 @@ class Equation:
return Equation(Operation.CONST, None, None, Const(self.value.value))
if self.op == Operation.VAR:
return Equation(Operation.VAR, None, None, Var(self.value.name, self.value.degree))
if self.op in {Operation.SIN, Operation.COS}:
return Equation(self.op, None, None, self.value.copy())
return Equation(self.op, self.left.copy(), self.right.copy(), None)
def diff(self):
@ -379,6 +382,10 @@ class Equation:
if self.op == Operation.DIV:
return (self.left.diff()*self.right.copy() - self.left.copy()*self.right.diff()) \
/ (self.right.copy()*self.right.copy())
if self.op == Operation.SIN:
return self.value.diff() * Equation(Operation.COS, None, None, self.value.copy())
if self.op == Operation.COS:
return Const(-1) * self.value.diff() * Equation(Operation.SIN, None, None, self.value.copy())
def partial(self, var_name):
if self.op == Operation.CONST:
@ -397,6 +404,10 @@ class Equation:
if self.op == Operation.DIV:
return (self.left.partial(var_name)*self.right.copy() - self.left.copy()*self.right.partial(var_name)) \
/ (self.right.copy()*self.right.copy())
if self.op == Operation.SIN:
return self.value.partial(var_name) * Equation(Operation.COS, None, None, self.value.copy())
if self.op == Operation.COS:
return Const(-1) * self.value.partial(var_name) * Equation(Operation.SIN, None, None, self.value.copy())
def evaluate(self, dico):
if self.op == Operation.CONST:
@ -411,17 +422,23 @@ class Equation:
return self.left.evaluate(dico) * self.right.evaluate(dico)
if self.op == Operation.DIV:
return self.left.evaluate(dico) / self.right.evaluate(dico)
if self.op == Operation.SIN:
return np.sin(self.value.evaluate(dico))
if self.op == Operation.COS:
return np.cos(self.value.evaluate(dico))
def solve(self, dico, tmax=10, dt=0.01):
self.simplify()
variables = self.getAllVar()
equations = []
print([v.name for v in variables])
# print([v.name for v in variables])
for var in variables:
equations.append(self.partial(var.diff().name).diff() - self.partial(var.name))
unknown = self.getUnknown(dico)
for eq in equations:
eq.simplify()
unknown = unknown.union(eq.getUnknown(dico))
t = 0
@ -430,6 +447,8 @@ class Equation:
for var in unknown:
dico[var.name] = 0.
# print([var.name for var in unknown])
# print(equations[0])
assert(len(unknown) == len(equations))
n = len(unknown)
@ -437,9 +456,13 @@ class Equation:
unknown = list(unknown)
equations = list(equations)
while t <= tmax:
for t in tqdm([n * dt for n in range(int(tmax/dt))]):
err = 1
while err > 10**-6:
iterations = 0
max_iteration = 50
while err > 10**-6 and iterations < max_iteration:
iterations += 1
# jacobian
J = np.zeros((n, n))
F = np.zeros(n)
@ -483,17 +506,102 @@ class Equation:
return {self.value.copy()}
else:
return {Var(self.value.name[2*self.value.degree:], 0)}
if self.op in {Operation.SIN, Operation.COS}:
return self.value.getAllVar()
return self.left.getAllVar().union(self.right.getAllVar())
def getUnknown(self, dico):
# print(self)
if self.op == Operation.CONST:
return set()
if self.op == Operation.VAR:
if self.value.name not in dico:
return {self.value}
return set()
if self.op in {Operation.SIN, Operation.COS}:
return self.value.getUnknown(dico)
return self.left.getUnknown(dico).union(self.right.getUnknown(dico))
def simplify(self):
if self.left != None:
self.left.simplify()
if self.right != None:
self.right.simplify()
if self.op in {Operation.SIN, Operation.COS}:
self.value.simplify()
if self.op == Operation.CONST:
pass
if self.op == Operation.VAR:
pass
if self.op == Operation.ADD:
if self.left.op == Operation.CONST and self.right.op == Operation.CONST:
self.op = Operation.CONST
self.value = Const(self.left.value.value + self.right.value.value)
self.left = None
self.right = None
elif self.left.op == Operation.CONST and self.left.value.value == 0:
self.op = self.right.op
self.left = self.right.left
self.value = self.right.value
self.right = self.right.right
elif self.right.op == Operation.CONST and self.right.value.value == 0:
self.op = self.left.op
self.right = self.left.right
self.value = self.left.value
self.left = self.left.left
if self.op == Operation.SUB:
if self.left.op == Operation.CONST and self.right.op == Operation.CONST:
self.op = Operation.CONST
self.value = Const(self.left.value.value - self.right.value.value)
self.left = None
self.right = None
elif self.right.op == Operation.CONST and self.right.value.value == 0:
self = self.left
if self.op == Operation.MULT:
if self.left.op == Operation.CONST and self.right.op == Operation.CONST:
self.op = Operation.CONST
self.value = Const(self.left.value.value * self.right.value.value)
self.left = None
self.right = None
elif self.left.op == Operation.CONST and self.left.value.value == 0:
self.op = Operation.CONST
self.left = None
self.right = None
self.value = Const(0)
elif self.right.op == Operation.CONST and self.right.value.value == 0:
self.op = Operation.CONST
self.left = None
self.right = None
self.value = Const(0)
elif self.left.op == Operation.CONST and self.left.value.value == 1:
self.op = self.right.op
self.left = self.right.left
self.value = self.right.value
self.right = self.right.right
elif self.right.op == Operation.CONST and self.right.value.value == 1:
self.op = self.left.op
self.right = self.left.right
self.value = self.left.value
self.left = self.left.left
if self.op == Operation.SIN:
if self.value.op == Operation.CONST:
self.op = Operation.CONST
self.left = None
self.right = None
self.value = Const(np.sin(self.value.value))
if self.op == Operation.COS:
if self.value.op == Operation.CONST:
self.op = Operation.CONST
self.left = None
self.right = None
self.value = Const(np.cos(self.value.value))
def __str__(self):
if self.op == Operation.CONST:
return str(self.value.value)
@ -507,6 +615,10 @@ class Equation:
return f"({str(self.left)})*({str(self.right)})"
if self.op == Operation.DIV:
return f"({str(self.left)})/({str(self.right)})"
if self.op == Operation.SIN:
return f"sin({str(self.value)})"
if self.op == Operation.COS:
return f"cos({str(self.value)})"
def __add__(self, other):
if other.type == "Const":
@ -595,3 +707,23 @@ class Equation:
def __rtruediv__(self, other):
if isinstance(other, (int, float)):
return Const(other) / self
def cos(value):
if isinstance(value, (float, int)):
return Equation(Operation.CONST, None, None, np.cos(value))
if value.type == "Const":
return Equation(Operation.CONST, None, None, np.cos(value.value))
if value.type == "Var":
return Equation(Operation.COS, None, None, Equation(Operation.VAR, None, None, value.copy()))
if value.type == "Equation":
return Equation(Operation.COS, None, None, value.copy())
def sin(value):
if isinstance(value, (float, int)):
return Equation(Operation.CONST, None, None, np.sin(value))
if value.type == "Const":
return Equation(Operation.CONST, None, None, np.sin(value.value))
if value.type == "Var":
return Equation(Operation.SIN, None, None, Equation(Operation.VAR, None, None, value.copy()))
if value.type == "Equation":
return Equation(Operation.SIN, None, None, value.copy())

56
pendule_a_ressort.py Normal file
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@ -0,0 +1,56 @@
import legrandchien as lgc
import matplotlib.pyplot as plt
import matplotlib.animation as animation
import numpy as np
g = lgc.Const(10)
m = lgc.Const(1)
k = lgc.Const(10)
r0 = lgc.Const(1)
theta = lgc.Var("theta")
r = lgc.Var("r")
x = r * lgc.cos(theta)
y = r * lgc.sin(theta)
T = 0.5 * m * (x.diff()*x.diff() + y.diff()*y.diff())
V = m * g * r * lgc.cos(theta) + k * (r - r0) * (r - r0)
L = T - V
dico = {
"theta" : -3.14/2,
"d_theta" : 0,
"r" : 1.2,
"d_r" : 0,
}
data = L.solve(dico, 10, 0.01)
# Extraire les positions
times = sorted(data.keys())
positions = [data[t] for t in times]
x_positions = [p["r"] * np.sin(p["theta"]) for p in positions]
y_positions = [p["r"] * np.cos(p["theta"]) for p in positions]
# Créer la figure et l'axe
fig, ax = plt.subplots(figsize=(8, 8))
ax.set_xlim(-3, 3)
ax.set_ylim(-3, 3)
ax.set_xlabel("X (m)")
ax.set_ylabel("Y (m)")
ax.grid(True)
line, = ax.plot([], [], 'o-', lw=2, markersize=8)
trace, = ax.plot([], [], 'r-', alpha=0.3, lw=1)
def animate(frame):
line.set_data([0, x_positions[frame]], [0, y_positions[frame]])
trace.set_data(x_positions[:frame+1], y_positions[:frame+1])
return line, trace
anim = animation.FuncAnimation(fig, animate, frames=len(x_positions), interval=50, blit=True, repeat=True)
plt.show()