def test_genn(self):
import numpy as np
import matplotlib.pyplot as plt
from smt.surrogate_models.genn import GENN, load_smt_data
# Training data
lower_bound = -np.pi
upper_bound = np.pi
number_of_training_points = 4
xt = np.linspace(lower_bound, upper_bound, number_of_training_points)
yt = xt * np.sin(xt)
dyt_dxt = np.sin(xt) + xt * np.cos(xt)
# Validation data
number_of_validation_points = 30
xv = np.linspace(lower_bound, upper_bound, number_of_validation_points)
yv = xv * np.sin(xv)
dyv_dxv = np.sin(xv) + xv * np.cos(xv)
# Truth model
x = np.arange(lower_bound, upper_bound, 0.01)
y = x * np.sin(x)
# GENN
genn = GENN()
genn.options[
"alpha"] = 0.1 # learning rate that controls optimizer step size
genn.options[
"beta1"] = 0.9 # tuning parameter to control ADAM optimization
genn.options[
"beta2"] = 0.99 # tuning parameter to control ADAM optimization
genn.options[
"lambd"] = 0.1 # lambd = 0. = no regularization, lambd > 0 = regularization
genn.options[
"gamma"] = 1.0 # gamma = 0. = no grad-enhancement, gamma > 0 = grad-enhancement
genn.options["deep"] = 2 # number of hidden layers
genn.options["wide"] = 6 # number of nodes per hidden layer
genn.options[
"mini_batch_size"] = 64 # used to divide data into training batches (use for large data sets)
genn.options["num_epochs"] = 20 # number of passes through data
genn.options[
"num_iterations"] = 100 # number of optimizer iterations per mini-batch
genn.options["is_print"] = True # print output (or not)
load_smt_data(
genn, xt, yt, dyt_dxt
) # convenience function to read in data that is in SMT format
genn.train() # API function to train model
genn.plot_training_history(
) # non-API function to plot training history (to check convergence)
genn.goodness_of_fit(
xv, yv,
dyv_dxv) # non-API function to check accuracy of regression
y_pred = genn.predict_values(
x) # API function to predict values at new (unseen) points
# Plot
fig, ax = plt.subplots()
ax.plot(x, y_pred)
ax.plot(x, y, "k--")
ax.plot(xv, yv, "ro")
ax.plot(xt, yt, "k+", mew=3, ms=10)
ax.set(xlabel="x", ylabel="y", title="GENN")
ax.legend(["Predicted", "True", "Test", "Train"])
plt.show()
def run_demo_1D(is_gradient_enhancement=True): # pragma: no cover
"""Test and demonstrate GENN using a 1D example"""
# Test function
f = lambda x: x * np.sin(x)
df_dx = lambda x: np.sin(x) + x * np.cos(x)
# Domain
lb = -np.pi
ub = np.pi
# Training data
m = 4
xt = np.linspace(lb, ub, m)
yt = f(xt)
dyt_dxt = df_dx(xt)
# Validation data
xv = lb + np.random.rand(30, 1) * (ub - lb)
yv = f(xv)
dyv_dxv = df_dx(xv)
# Initialize GENN object
genn = GENN()
genn.options["alpha"] = 0.05
genn.options["beta1"] = 0.9
genn.options["beta2"] = 0.99
genn.options["lambd"] = 0.05
genn.options["gamma"] = int(is_gradient_enhancement)
genn.options["deep"] = 2
genn.options["wide"] = 6
genn.options["mini_batch_size"] = 64
genn.options["num_epochs"] = 25
genn.options["num_iterations"] = 100
genn.options["seed"] = SEED
genn.options["is_print"] = True
# Load data
load_smt_data(genn, xt, yt, dyt_dxt)
# Train
genn.train()
genn.plot_training_history()
genn.goodness_of_fit(xv, yv, dyv_dxv)
# Plot comparison
if genn.options["gamma"] == 1.0:
title = 'with gradient enhancement'
else:
title = 'without gradient enhancement'
x = np.arange(lb, ub, 0.01)
y = f(x)
y_pred = genn.predict_values(x)
fig, ax = plt.subplots()
ax.plot(x, y_pred)
ax.plot(x, y, 'k--')
ax.plot(xv, yv, 'ro')
ax.plot(xt, yt, 'k+', mew=3, ms=10)
ax.set(xlabel='x', ylabel='y', title=title)
ax.legend(['Predicted', 'True', 'Test', 'Train'])
plt.show()
