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ode_system.py
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ode_system.py
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from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import numpy as np
import tensorflow as tf
import deepxde as dde
def main():
def ode_system(x, y):
"""ODE system.
dy1/dx = y2
dy2/dx = -y1
"""
y1, y2 = y[:, 0:1], y[:, 1:]
dy1_x = tf.gradients(y1, x)[0]
dy2_x = tf.gradients(y2, x)[0]
return [dy1_x - y2, dy2_x + y1]
def boundary(x, on_boundary):
return on_boundary and np.isclose(x[0], 0)
def func(x):
"""
y1 = sin(x)
y2 = cos(x)
"""
return np.hstack((np.sin(x), np.cos(x)))
geom = dde.geometry.Interval(0, 10)
bc1 = dde.DirichletBC(geom, np.sin, boundary, component=0)
bc2 = dde.DirichletBC(geom, np.cos, boundary, component=1)
data = dde.data.PDE(geom, 2, ode_system, [bc1, bc2], 35, 2, func=func, num_test=100)
layer_size = [1] + [50] * 3 + [2]
activation = "tanh"
initializer = "Glorot uniform"
net = dde.maps.FNN(layer_size, activation, initializer)
model = dde.Model(data, net)
model.compile("adam", lr=0.001, metrics=["l2 relative error"])
losshistory, train_state = model.train(epochs=20000)
dde.saveplot(losshistory, train_state, issave=True, isplot=True)
if __name__ == "__main__":
main()