def plot_roc_curve(model, partition):
r"""Display ROC Curves with Cross-Validation.
Parameters
----------
model : alphapy.Model
The model object with plotting specifications.
partition : alphapy.Partition
Reference to the dataset.
Returns
-------
None : None
References
----------
http://scikit-learn.org/stable/modules/model_evaluation.html#receiver-operating-characteristic-roc
"""
logger.info("Generating ROC Curves")
pstring = datasets[partition]
# For classification only
if model.specs['model_type'] != ModelType.classification:
logger.info('ROC Curves are for classification only')
return None
# Get X, Y for correct partition.
X, y = get_partition_data(model, partition)
# Initialize plot parameters.
plt.style.use('classic')
plt.figure()
lw = 2
# Plot a ROC Curve for each algorithm.
for algo in model.algolist:
logger.info("ROC Curve for Algorithm: %s", algo)
# compute ROC curve and ROC area for each class
probas = model.probas[(algo, partition)]
fpr, tpr, _ = roc_curve(y, probas)
roc_auc = auc(fpr, tpr)
plt.plot(fpr, tpr, lw=lw, label='%s (area = %0.2f)' % (algo, roc_auc))
# draw the luck line
plt.plot([0, 1], [0, 1], linestyle='--', color='k', label='Luck')
# define plot characteristics
plt.xlim([-0.05, 1.05])
plt.ylim([-0.05, 1.05])
plt.xlabel('False Positive Rate')
plt.ylabel('True Positive Rate')
title = BSEP.join([algo, "ROC Curve [", pstring, "]"])
plt.title(title)
plt.legend(loc="lower right")
# save chart
plot_dir = get_plot_directory(model)
write_plot('matplotlib', plt, 'roc_curve', pstring, plot_dir)
def plot_validation_curve(model, partition, pname, prange):
r"""Generate scikit-learn validation curves.
Parameters
----------
model : alphapy.Model
The model object with plotting specifications.
partition : alphapy.Partition
Reference to the dataset.
pname : str
Name of the hyperparameter to test.
prange : numpy array
The values of the hyperparameter that will be evaluated.
Returns
-------
None : None
References
----------
http://scikit-learn.org/stable/auto_examples/model_selection/plot_validation_curve.html#sphx-glr-auto-examples-model-selection-plot-validation-curve-py
"""
logger.info("Generating Validation Curves")
plot_dir = get_plot_directory(model)
pstring = datasets[partition]
# Extract model parameters.
cv_folds = model.specs['cv_folds']
n_jobs = model.specs['n_jobs']
scorer = model.specs['scorer']
verbosity = model.specs['verbosity']
# Get X, Y for correct partition.
X, y = get_partition_data(model, partition)
# Define plotting constants.
spacing = 0.5
alpha = 0.2
# Calculate a validation curve for each algorithm.
for algo in model.algolist:
logger.info("Algorithm: %s", algo)
# get estimator
estimator = model.estimators[algo]
# set up plot
train_scores, test_scores = validation_curve(estimator,
X,
y,
param_name=pname,
param_range=prange,
cv=cv_folds,
scoring=scorer,
n_jobs=n_jobs)
train_scores_mean = np.mean(train_scores, axis=1)
train_scores_std = np.std(train_scores, axis=1)
test_scores_mean = np.mean(test_scores, axis=1)
test_scores_std = np.std(test_scores, axis=1)
# set up figure
plt.style.use('classic')
plt.figure()
# plot learning curves
title = BSEP.join([algo, "Validation Curve [", pstring, "]"])
plt.title(title)
# x-axis
x_min, x_max = min(prange) - spacing, max(prange) + spacing
plt.xlabel(pname)
plt.xlim(x_min, x_max)
# y-axis
plt.ylabel("Score")
plt.ylim(0.0, 1.1)
# plot scores
plt.plot(prange, train_scores_mean, label="Training Score", color="r")
plt.fill_between(prange,
train_scores_mean - train_scores_std,
train_scores_mean + train_scores_std,
alpha=alpha,
color="r")
plt.plot(prange,
test_scores_mean,
label="Cross-Validation Score",
color="g")
plt.fill_between(prange,
test_scores_mean - test_scores_std,
test_scores_mean + test_scores_std,
alpha=alpha,
color="g")
plt.legend(loc="best") # save the plot
tag = USEP.join([pstring, algo])
write_plot('matplotlib', plt, 'validation_curve', tag, plot_dir)
def plot_learning_curve(model, partition):
r"""Generate learning curves for a given partition.
Parameters
----------
model : alphapy.Model
The model object with plotting specifications.
partition : alphapy.Partition
Reference to the dataset.
Returns
-------
None : None
References
----------
http://scikit-learn.org/stable/auto_examples/ensemble/plot_forest_importances.html
"""
logger.info("Generating Learning Curves")
plot_dir = get_plot_directory(model)
pstring = datasets[partition]
# Extract model parameters.
cv_folds = model.specs['cv_folds']
n_jobs = model.specs['n_jobs']
seed = model.specs['seed']
shuffle = model.specs['shuffle']
verbosity = model.specs['verbosity']
# Get original estimators
estimators = get_estimators(model)
# Get X, Y for correct partition.
X, y = get_partition_data(model, partition)
# Set cross-validation parameters to get mean train and test curves.
cv = StratifiedKFold(n_splits=cv_folds, shuffle=shuffle, random_state=seed)
# Plot a learning curve for each algorithm.
ylim = (0.4, 1.01)
for algo in model.algolist:
logger.info("Learning Curve for Algorithm: %s", algo)
# get estimator
est = estimators[algo].estimator
# plot learning curve
title = BSEP.join([algo, "Learning Curve [", pstring, "]"])
# set up plot
plt.style.use('classic')
plt.figure()
plt.title(title)
if ylim is not None:
plt.ylim(*ylim)
plt.xlabel("Training Examples")
plt.ylabel("Score")
# call learning curve function
train_sizes = np.linspace(0.1, 1.0, cv_folds)
train_sizes, train_scores, test_scores = \
learning_curve(est, X, y, train_sizes=train_sizes, cv=cv,
n_jobs=n_jobs, verbose=verbosity)
train_scores_mean = np.mean(train_scores, axis=1)
train_scores_std = np.std(train_scores, axis=1)
test_scores_mean = np.mean(test_scores, axis=1)
test_scores_std = np.std(test_scores, axis=1)
plt.grid()
# plot data
plt.fill_between(train_sizes,
train_scores_mean - train_scores_std,
train_scores_mean + train_scores_std,
alpha=0.1,
color="r")
plt.fill_between(train_sizes,
test_scores_mean - test_scores_std,
test_scores_mean + test_scores_std,
alpha=0.1,
color="g")
plt.plot(train_sizes,
train_scores_mean,
'o-',
color="r",
label="Training Score")
plt.plot(train_sizes,
test_scores_mean,
'o-',
color="g",
label="Cross-Validation Score")
plt.legend(loc="lower right")
# save the plot
tag = USEP.join([pstring, algo])
write_plot('matplotlib', plt, 'learning_curve', tag, plot_dir)
def plot_importance(model, partition):
r"""Display scikit-learn feature importances.
Parameters
----------
model : alphapy.Model
The model object with plotting specifications.
partition : alphapy.Partition
Reference to the dataset.
Returns
-------
None : None
References
----------
http://scikit-learn.org/stable/auto_examples/ensemble/plot_forest_importances.html
"""
logger.info("Generating Feature Importance Plots")
plot_dir = get_plot_directory(model)
pstring = datasets[partition]
# For each algorithm that has importances, generate the plot.
n_top = 20
for algo in model.algolist:
logger.info("Feature Importances for Algorithm: %s", algo)
try:
# get feature importances
importances = np.array(model.importances[algo])
imp_flag = True
except:
imp_flag = False
if imp_flag:
# sort the importances by index
indices = np.argsort(importances)[::-1]
# get feature names
feature_names = np.array(model.fnames_algo[algo])
n_features = len(feature_names)
# log the feature ranking
logger.info("Feature Ranking:")
n_min = min(n_top, n_features)
for i in range(n_min):
logger.info("%d. %s (%f)" % (i + 1, feature_names[indices[i]],
importances[indices[i]]))
# plot the feature importances
title = BSEP.join([algo, "Feature Importances [", pstring, "]"])
plt.figure()
plt.title(title)
plt.barh(range(n_min), importances[indices][:n_min][::-1])
plt.yticks(range(n_min), feature_names[indices][:n_min][::-1])
plt.ylim([-1, n_min])
plt.xlabel('Relative Importance')
# save the plot
tag = USEP.join([pstring, algo])
write_plot('matplotlib', plt, 'feature_importance', tag, plot_dir)
else:
logger.info("No Feature Importances for %s" % algo)
def plot_candlestick(df, symbol, datecol='date', directory=None):
r"""Plot time series data.
Parameters
----------
df : pandas.DataFrame
The dataframe containing the ``target`` feature.
symbol : str
Unique identifier of the data to plot.
datecol : str, optional
The name of the date column.
directory : str, optional
The full specification of the plot location.
Returns
-------
None : None.
Notes
-----
The dataframe ``df`` must contain these columns:
* ``open``
* ``high``
* ``low``
* ``close``
References
----------
http://bokeh.pydata.org/en/latest/docs/gallery/candlestick.html
"""
df[datecol] = pd.to_datetime(df[datecol])
mids = (df.open + df.close) / 2
spans = abs(df.close - df.open)
inc = df.close > df.open
dec = df.open > df.close
w = 12 * 60 * 60 * 1000 # half day in ms
TOOLS = "pan, wheel_zoom, box_zoom, reset, save"
p = figure(x_axis_type="datetime",
tools=TOOLS,
plot_width=1000,
toolbar_location="left")
p.title = BSEP.join([symbol.upper(), "Candlestick"])
p.xaxis.major_label_orientation = math.pi / 4
p.grid.grid_line_alpha = 0.3
p.segment(df.date, df.high, df.date, df.low, color="black")
p.rect(df.date[inc],
mids[inc],
w,
spans[inc],
fill_color="#D5E1DD",
line_color="black")
p.rect(df.date[dec],
mids[dec],
w,
spans[dec],
fill_color="#F2583E",
line_color="black")
# Save the plot
write_plot('bokeh', p, 'candlestick_chart', symbol, directory)
def plot_confusion_matrix(model, partition):
r"""Draw the confusion matrix.
Parameters
----------
model : alphapy.Model
The model object with plotting specifications.
partition : alphapy.Partition
Reference to the dataset.
Returns
-------
None : None
References
----------
http://scikit-learn.org/stable/modules/model_evaluation.html#confusion-matrix
"""
logger.info("Generating Confusion Matrices")
plot_dir = get_plot_directory(model)
pstring = datasets[partition]
# For classification only
if model.specs['model_type'] != ModelType.classification:
logger.info('Confusion Matrix is for classification only')
return None
# Get X, Y for correct partition.
X, y = get_partition_data(model, partition)
for algo in model.algolist:
logger.info("Confusion Matrix for Algorithm: %s", algo)
# get predictions for this partition
y_pred = model.preds[(algo, partition)]
# compute confusion matrix
cm = confusion_matrix(y, y_pred)
logger.info('Confusion Matrix:')
logger.info('%s', cm)
# initialize plot
np.set_printoptions(precision=2)
plt.style.use('classic')
plt.figure()
# plot the confusion matrix
cmap = plt.cm.Blues
plt.imshow(cm, interpolation='nearest', cmap=cmap)
title = BSEP.join([algo, "Confusion Matrix [", pstring, "]"])
plt.title(title)
plt.colorbar()
# set up x and y axes
y_values, y_counts = np.unique(y, return_counts=True)
tick_marks = np.arange(len(y_values))
plt.xticks(tick_marks, y_values, rotation=45)
plt.yticks(tick_marks, y_values)
# normalize confusion matrix
cmn = cm.astype('float') / cm.sum(axis=1)[:, np.newaxis]
# place text in square of confusion matrix
thresh = (cm.max() + cm.min()) / 2.0
for i, j in product(list(range(cm.shape[0])),
list(range(cm.shape[1]))):
cmr = round(cmn[i, j], 3)
plt.text(j,
i,
cmr,
horizontalalignment="center",
color="white" if cm[i, j] > thresh else "black")
# labels
plt.tight_layout()
plt.ylabel('True Label')
plt.xlabel('Predicted Label')
# save the chart
tag = USEP.join([pstring, algo])
write_plot('matplotlib', plt, 'confusion', tag, plot_dir)
def vexec(f, v, vfuncs=None):
r"""Add a variable to the given dataframe.
This is the core function for adding a variable to a dataframe.
The default variable functions are already defined locally
in ``alphapy.var``; however, you may want to define your
own variable functions. If so, then the ``vfuncs`` parameter
will contain the list of modules and functions to be imported
and applied by the ``vexec`` function.
To write your own variable function, your function must have
a pandas *DataFrame* as an input parameter and must return
a pandas *Series* that represents the new variable.
Parameters
----------
f : pandas.DataFrame
Dataframe to contain the new variable.
v : str
Variable to add to the dataframe.
vfuncs : dict, optional
Dictionary of external modules and functions.
Returns
-------
f : pandas.DataFrame
Dataframe with the new variable.
Other Parameters
----------------
Variable.variables : dict
Global dictionary of variables
"""
vxlag, root, plist, lag = vparse(v)
logger.debug("vexec : %s", v)
logger.debug("vxlag : %s", vxlag)
logger.debug("root : %s", root)
logger.debug("plist : %s", plist)
logger.debug("lag : %s", lag)
if vxlag not in f.columns:
if root in Variable.variables:
logger.debug("Found variable %s: ", root)
vroot = Variable.variables[root]
expr = vroot.expr
expr_new = vsub(vxlag, expr)
estr = "%s" % expr_new
estr = BSEP.join([vxlag, '=', estr])
logger.debug("Expression: %s", estr)
# pandas eval
f.eval(estr, inplace=True)
else:
logger.debug("Did not find variable: %s", root)
# Must be a function call
func_name = root
# Convert the parameter list and prepend the data frame
newlist = []
for p in plist:
try:
newlist.append(int(p))
except:
try:
newlist.append(float(p))
except:
newlist.append(p)
newlist.insert(0, f)
# Find the module and function
module = None
if vfuncs:
for m in vfuncs:
funcs = vfuncs[m]
if func_name in funcs:
module = m
break
# If the module was found, import the external treatment function,
# else search the local namespace.
if module:
ext_module = import_module(module)
func = getattr(my_module, func_name)
# Create the variable by calling the function
f[v] = func(*newlist)
else:
modname = globals()['__name__']
module = sys.modules[modname]
if func_name in dir(module):
func = getattr(module, func_name)
# Create the variable
f[v] = func(*newlist)
else:
logger.debug("Could not find function %s", func_name)
# if necessary, add the lagged variable
if lag > 0 and vxlag in f.columns:
f[v] = f[vxlag].shift(lag)
# output frame
return f
