def parallel_function(dataset_name,
method,
tol=1e-5,
n_outer=50,
tolerance_decrease='constant'):
# load data
X, y = fetch_libsvm(dataset_name)
y -= np.mean(y)
# compute alpha_max
alpha_max = np.abs(X.T @ y).max() / len(y)
if model_name == "logreg":
alpha_max /= 2
alpha_min = alpha_max * dict_palphamin[dataset_name]
if model_name == "enet":
estimator = linear_model.ElasticNet(fit_intercept=False,
max_iter=10_000,
warm_start=True,
tol=tol)
model = ElasticNet(estimator=estimator)
elif model_name == "logreg":
model = SparseLogreg(estimator=estimator)
# TODO improve this
try:
n_outer = dict_n_outers[dataset_name, method]
except Exception:
n_outer = 20
size_loop = 2
for _ in range(size_loop):
if model_name == "lasso" or model_name == "enet":
sub_criterion = HeldOutMSE(None, None)
elif model_name == "logreg":
criterion = HeldOutLogistic(None, None)
kf = KFold(n_splits=5, shuffle=True, random_state=42)
criterion = CrossVal(sub_criterion, cv=kf)
algo = ImplicitForward(tol_jac=1e-3)
monitor = Monitor()
t_max = dict_t_max[dataset_name]
if method == 'grid_search':
num1D = dict_point_grid_search[dataset_name]
alpha1D = np.geomspace(alpha_max, alpha_min, num=num1D)
alphas = [np.array(i) for i in product(alpha1D, alpha1D)]
grid_search(algo,
criterion,
model,
X,
y,
alpha_min,
alpha_max,
monitor,
max_evals=100,
tol=tol,
alphas=alphas)
elif method == 'random' or method == 'bayesian':
hyperopt_wrapper(algo,
criterion,
model,
X,
y,
alpha_min,
alpha_max,
monitor,
max_evals=30,
tol=tol,
method=method,
size_space=2,
t_max=t_max)
elif method.startswith("implicit_forward"):
# do gradient descent to find the optimal lambda
alpha0 = np.array([alpha_max / 100, alpha_max / 100])
n_outer = 30
if method == 'implicit_forward':
optimizer = GradientDescent(n_outer=n_outer,
p_grad_norm=1,
verbose=True,
tol=tol,
t_max=t_max)
else:
optimizer = GradientDescent(n_outer=n_outer,
p_grad_norm=1,
verbose=True,
tol=tol,
t_max=t_max,
tol_decrease="geom")
grad_search(algo, criterion, model, optimizer, X, y, alpha0,
monitor)
else:
raise NotImplementedError
monitor.times = np.array(monitor.times)
monitor.objs = np.array(monitor.objs)
monitor.objs_test = 0 # TODO
monitor.alphas = np.array(monitor.alphas)
return (dataset_name, method, tol, n_outer, tolerance_decrease,
monitor.times, monitor.objs, monitor.objs_test, monitor.alphas,
alpha_max, model_name)
Y,
results.T / scaling_factor,
levels=levels,
cmap="viridis")
ax.scatter(X,
Y,
s=10,
c="orange",
marker="o",
label="$0$th order (grid search)",
clip_on=False)
for method in dict_monitor.keys():
if method != 'grid_search':
monitor = dict_monitor[method]
monitor.alphas = np.array(monitor.alphas)
n_outer = len(monitor.objs)
color = discrete_color(n_outer, dict_colors[method])
ax.scatter(monitor.alphas[:, 0] / alpha_max,
monitor.alphas[:, 1] / alpha_max,
s=50,
color=color,
marker="X",
label="$1$st order",
clip_on=False)
ax.set_xlim(X.min(), X.max())
ax.set_xlabel("L1 regularization")
ax.set_ylabel("L2 regularization")
ax.set_ylim(Y.min(), Y.max())
ax.set_title("Elastic net held out prediction loss on test set")
cb = fig.colorbar(cp)
