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RROMPy/examples/8_damped_mass_chain/damped_mass_chain_engine.py
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damped_mass_chain_engine.py
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### example from Lohmann, Eid. Efficient Order Reduction of Parametric and
### Nonlinear Models by Superposition of Locally Reduced Models.
import numpy as np
import matplotlib.pyplot as plt
from rrompy.hfengines.scipy_engines import (OscillatorProblemEngine,
AugmentedOscillatorProblemEngine)
from rrompy.utilities.expression import Expression as Expr
lines = ["-", "--", ":", "-."] * 5
def bode(freq, mus, models):
x = np.hstack((freq.reshape(-1, 1), np.tile(np.array(mus).reshape(1, -1),
(len(freq), 1))))
fig = plt.figure(figsize = (7.5, 4.5))
ax = fig.add_subplot(1, 1, 1)
for model, line in zip(models, lines[: len(models)]):
ax.semilogx(x[:, 0], 20 * np.log10(np.abs(model(x).data.T)), line)
ax.set_xlim(freq[0], freq[-1])
ax.set_xlabel("omega")
ax.set_ylabel("output")
ax.set_title(str(mus))
ax.grid()
plt.show()
return fig
def bodeLin(freq, mus, models):
x = np.hstack((freq.reshape(-1, 1), np.tile(np.array(mus).reshape(1, -1),
(len(freq), 1))))
fig = plt.figure(figsize = (7.5, 4.5))
ax = fig.add_subplot(1, 1, 1)
for model, line in zip(models, lines[: len(models)]):
ax.plot(x[:, 0], 20 * np.log10(np.abs(model(x).data.T)), line)
ax.set_xlim(freq[0], freq[-1])
ax.set_xlabel("omega")
ax.set_ylabel("output")
ax.set_title(str(mus))
ax.grid()
plt.show()
return fig
def bodeLog(freq, mus, models):
x = np.hstack((freq.reshape(-1, 1), np.tile(np.array(mus).reshape(1, -1),
(len(freq), 1))))
fig = plt.figure(figsize = (7.5, 4.5))
ax = fig.add_subplot(1, 1, 1)
for model, line in zip(models, lines[: len(models)]):
ax.semilogx(10. ** x[:, 0], 20 * np.log10(np.abs(model(x).data.T)),
line)
ax.set_xlim(10 ** freq[0], 10 ** freq[-1])
ax.set_xlabel("omega")
ax.set_ylabel("output")
ax.set_title(str(mus))
ax.grid()
plt.show()
return fig
class MassChainEngine(OscillatorProblemEngine): pass
class AugmentedMassChainEngine(AugmentedOscillatorProblemEngine): pass
class MassChainEngineLog(MassChainEngine):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self._affinePoly = False
deg = [1] + [0] * (self.npar - 1)
for j in range(self.npar):
self.thAs[3 * j] = [Expr(self.thAs[3 * j][0])]
self.thAs[3 * j + 1] = [Expr(self.thAs[3 * j][0]
+ ('*', (10., "**", ("prod", {"axis" : 1},
("data", "x", "**", deg)))))]
self.thAs[3 * j + 2] = [Expr(self.thAs[3 * j][0]
+ ('*', (100., "**", ("prod", {"axis" : 1},
("data", "x", "**", deg)))))]
class AugmentedMassChainEngineLog(AugmentedMassChainEngine):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self._affinePoly = False
deg = [1] + [0] * (self.npar - 1)
for j in range(self.npar):
self.thAs[2 * j] = [Expr(self.thAs[2 * j][0])]
self.thAs[2 * j + 1] = [Expr(self.thAs[2 * j][0]
+ ('*', (10., "**", ("prod", {"axis" : 1},
("data", "x", "**", deg)))))]
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