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Minor edits to coding style (#2835)

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* Some minor changes to the code style

Some minor changes to the code style in file basic_walkthrough.py

* coding style changes

* coding style changes arrcording PEP8

* Update basic_walkthrough.py
This commit is contained in:
LevineHuang 2017-10-27 11:12:54 +08:00 committed by Yuan (Terry) Tang
parent d9d5293cdb
commit 91af8f7106
10 changed files with 51 additions and 52 deletions
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34
demo/guide-python/basic_walkthrough.py
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@ -10,22 +10,22 @@ dtrain = xgb.DMatrix('../data/agaricus.txt.train')
dtest = xgb.DMatrix('../data/agaricus.txt.test')
# specify parameters via map, definition are same as c++ version
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic' }
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic'}
# specify validations set to watch performance
watchlist = [(dtest,'eval'), (dtrain,'train')]
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
num_round = 2
bst = xgb.train(param, dtrain, num_round, watchlist)
# this is prediction
preds = bst.predict(dtest)
labels = dtest.get_label()
print ('error=%f' % ( sum(1 for i in range(len(preds)) if int(preds[i]>0.5)!=labels[i]) /float(len(preds))))
print('error=%f' % (sum(1 for i in range(len(preds)) if int(preds[i] > 0.5) != labels[i]) / float(len(preds))))
bst.save_model('0001.model')
# dump model
bst.dump_model('dump.raw.txt')
# dump model with feature map
bst.dump_model('dump.nice.txt','../data/featmap.txt')
bst.dump_model('dump.nice.txt', '../data/featmap.txt')
# save dmatrix into binary buffer
dtest.save_binary('dtest.buffer')
@ -36,7 +36,7 @@ bst2 = xgb.Booster(model_file='xgb.model')
dtest2 = xgb.DMatrix('dtest.buffer')
preds2 = bst2.predict(dtest2)
# assert they are the same
assert np.sum(np.abs(preds2-preds)) == 0
assert np.sum(np.abs(preds2 - preds)) == 0
# alternatively, you can pickle the booster
pks = pickle.dumps(bst2)
@ -44,11 +44,11 @@ pks = pickle.dumps(bst2)
bst3 = pickle.loads(pks)
preds3 = bst3.predict(dtest2)
# assert they are the same
assert np.sum(np.abs(preds3-preds)) == 0
assert np.sum(np.abs(preds3 - preds)) == 0
###
# build dmatrix from scipy.sparse
print ('start running example of build DMatrix from scipy.sparse CSR Matrix')
print('start running example of build DMatrix from scipy.sparse CSR Matrix')
labels = []
row = []; col = []; dat = []
i = 0
@ -59,24 +59,22 @@ for l in open('../data/agaricus.txt.train'):
k,v = it.split(':')
row.append(i); col.append(int(k)); dat.append(float(v))
i += 1
csr = scipy.sparse.csr_matrix((dat, (row,col)))
dtrain = xgb.DMatrix(csr, label = labels)
watchlist = [(dtest,'eval'), (dtrain,'train')]
csr = scipy.sparse.csr_matrix((dat, (row, col)))
dtrain = xgb.DMatrix(csr, label=labels)
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
bst = xgb.train(param, dtrain, num_round, watchlist)
print ('start running example of build DMatrix from scipy.sparse CSC Matrix')
print('start running example of build DMatrix from scipy.sparse CSC Matrix')
# we can also construct from csc matrix
csc = scipy.sparse.csc_matrix((dat, (row,col)))
csc = scipy.sparse.csc_matrix((dat, (row, col)))
dtrain = xgb.DMatrix(csc, label=labels)
watchlist = [(dtest,'eval'), (dtrain,'train')]
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
bst = xgb.train(param, dtrain, num_round, watchlist)
print ('start running example of build DMatrix from numpy array')
print('start running example of build DMatrix from numpy array')
# NOTE: npymat is numpy array, we will convert it into scipy.sparse.csr_matrix in internal implementation
# then convert to DMatrix
npymat = csr.todense()
dtrain = xgb.DMatrix(npymat, label = labels)
watchlist = [(dtest,'eval'), (dtrain,'train')]
dtrain = xgb.DMatrix(npymat, label=labels)
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
bst = xgb.train(param, dtrain, num_round, watchlist)

3
demo/guide-python/boost_from_prediction.py
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@ -20,5 +20,6 @@ ptest = bst.predict(dtest, output_margin=True)
dtrain.set_base_margin(ptrain)
dtest.set_base_margin(ptest)
print ('this is result of running from initial prediction')
print('this is result of running from initial prediction')
bst = xgb.train(param, dtrain, 1, watchlist)

24
demo/guide-python/cross_validation.py
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@ -7,30 +7,30 @@ dtrain = xgb.DMatrix('../data/agaricus.txt.train')
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic'}
num_round = 2
print ('running cross validation')
print('running cross validation')
# do cross validation, this will print result out as
# [iteration] metric_name:mean_value+std_value
# std_value is standard deviation of the metric
xgb.cv(param, dtrain, num_round, nfold=5,
metrics={'error'}, seed = 0,
metrics={'error'}, seed=0,
callbacks=[xgb.callback.print_evaluation(show_stdv=True)])
print ('running cross validation, disable standard deviation display')
print('running cross validation, disable standard deviation display')
# do cross validation, this will print result out as
# [iteration] metric_name:mean_value
res = xgb.cv(param, dtrain, num_boost_round=10, nfold=5,
metrics={'error'}, seed = 0,
metrics={'error'}, seed=0,
callbacks=[xgb.callback.print_evaluation(show_stdv=False),
xgb.callback.early_stop(3)])
print (res)
print ('running cross validation, with preprocessing function')
print(res)
print('running cross validation, with preprocessing function')
# define the preprocessing function
# used to return the preprocessed training, test data, and parameter
# we can use this to do weight rescale, etc.
# as a example, we try to set scale_pos_weight
def fpreproc(dtrain, dtest, param):
label = dtrain.get_label()
ratio = float(np.sum(label == 0)) / np.sum(label==1)
ratio = float(np.sum(label == 0)) / np.sum(label == 1)
param['scale_pos_weight'] = ratio
return (dtrain, dtest, param)
@ -39,18 +39,18 @@ def fpreproc(dtrain, dtest, param):
# then the return value of fpreproc will be used to generate
# results of that fold
xgb.cv(param, dtrain, num_round, nfold=5,
metrics={'auc'}, seed = 0, fpreproc = fpreproc)
metrics={'auc'}, seed=0, fpreproc=fpreproc)
###
# you can also do cross validation with cutomized loss function
# See custom_objective.py
##
print ('running cross validation, with cutomsized loss function')
print('running cross validation, with cutomsized loss function')
def logregobj(preds, dtrain):
labels = dtrain.get_label()
preds = 1.0 / (1.0 + np.exp(-preds))
grad = preds - labels
hess = preds * (1.0-preds)
hess = preds * (1.0 - preds)
return grad, hess
def evalerror(preds, dtrain):
labels = dtrain.get_label()
@ -58,5 +58,5 @@ def evalerror(preds, dtrain):
param = {'max_depth':2, 'eta':1, 'silent':1}
# train with customized objective
xgb.cv(param, dtrain, num_round, nfold = 5, seed = 0,
obj = logregobj, feval=evalerror)
xgb.cv(param, dtrain, num_round, nfold=5, seed=0,
obj=logregobj, feval=evalerror)

4
demo/guide-python/custom_objective.py
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@ -4,7 +4,7 @@ import xgboost as xgb
###
# advanced: customized loss function
#
print ('start running example to used customized objective function')
print('start running example to used customized objective function')
dtrain = xgb.DMatrix('../data/agaricus.txt.train')
dtest = xgb.DMatrix('../data/agaricus.txt.test')
@ -22,7 +22,7 @@ def logregobj(preds, dtrain):
labels = dtrain.get_label()
preds = 1.0 / (1.0 + np.exp(-preds))
grad = preds - labels
hess = preds * (1.0-preds)
hess = preds * (1.0 - preds)
return grad, hess
# user defined evaluation function, return a pair metric_name, result

4
demo/guide-python/external_memory.py
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@ -12,13 +12,13 @@ dtrain = xgb.DMatrix('../data/agaricus.txt.train#dtrain.cache')
dtest = xgb.DMatrix('../data/agaricus.txt.test#dtest.cache')
# specify validations set to watch performance
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic' }
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic'}
# performance notice: set nthread to be the number of your real cpu
# some cpu offer two threads per core, for example, a 4 core cpu with 8 threads, in such case set nthread=4
#param['nthread']=num_real_cpu
watchlist = [(dtest,'eval'), (dtrain,'train')]
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
num_round = 2
bst = xgb.train(param, dtrain, num_round, watchlist)

4
demo/guide-python/gamma_regression.py
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@ -15,11 +15,11 @@ dtest = xgb.DMatrix(data[4741:6773, 0:34], data[4741:6773, 34])
param = {'silent':1, 'objective':'reg:gamma', 'booster':'gbtree', 'base_score':3}
# the rest of settings are the same
watchlist = [(dtest,'eval'), (dtrain,'train')]
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
num_round = 30
# training and evaluation
bst = xgb.train(param, dtrain, num_round, watchlist)
preds = bst.predict(dtest)
labels = dtest.get_label()
print ('test deviance=%f' % (2 * np.sum((labels - preds) / preds - np.log(labels) + np.log(preds))))
print('test deviance=%f' % (2 * np.sum((labels - preds) / preds - np.log(labels) + np.log(preds))))

6
demo/guide-python/generalized_linear_model.py
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@ -11,7 +11,7 @@ dtest = xgb.DMatrix('../data/agaricus.txt.test')
# lambda is the L2 regularizer
# you can also set lambda_bias which is L2 regularizer on the bias term
param = {'silent':1, 'objective':'binary:logistic', 'booster':'gblinear',
'alpha': 0.0001, 'lambda': 1 }
'alpha': 0.0001, 'lambda': 1}
# normally, you do not need to set eta (step_size)
# XGBoost uses a parallel coordinate descent algorithm (shotgun),
@ -22,9 +22,9 @@ param = {'silent':1, 'objective':'binary:logistic', 'booster':'gblinear',
##
# the rest of settings are the same
##
watchlist = [(dtest,'eval'), (dtrain,'train')]
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
num_round = 4
bst = xgb.train(param, dtrain, num_round, watchlist)
preds = bst.predict(dtest)
labels = dtest.get_label()
print ('error=%f' % ( sum(1 for i in range(len(preds)) if int(preds[i]>0.5)!=labels[i]) /float(len(preds))))
print('error=%f' % (sum(1 for i in range(len(preds)) if int(preds[i] > 0.5) != labels[i]) / float(len(preds))))

10
demo/guide-python/predict_first_ntree.py
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@ -5,16 +5,16 @@ import xgboost as xgb
### load data in do training
dtrain = xgb.DMatrix('../data/agaricus.txt.train')
dtest = xgb.DMatrix('../data/agaricus.txt.test')
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic' }
watchlist = [(dtest,'eval'), (dtrain,'train')]
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic'}
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
num_round = 3
bst = xgb.train(param, dtrain, num_round, watchlist)
print ('start testing prediction from first n trees')
print('start testing prediction from first n trees')
### predict using first 1 tree
label = dtest.get_label()
ypred1 = bst.predict(dtest, ntree_limit=1)
# by default, we predict using all the trees
ypred2 = bst.predict(dtest)
print ('error of ypred1=%f' % (np.sum((ypred1>0.5)!=label) /float(len(label))))
print ('error of ypred2=%f' % (np.sum((ypred2>0.5)!=label) /float(len(label))))
print('error of ypred1=%f' % (np.sum((ypred1 > 0.5) != label) / float(len(label))))
print('error of ypred2=%f' % (np.sum((ypred2 > 0.5) != label) / float(len(label))))

6
demo/guide-python/predict_leaf_indices.py
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@ -4,8 +4,8 @@ import xgboost as xgb
### load data in do training
dtrain = xgb.DMatrix('../data/agaricus.txt.train')
dtest = xgb.DMatrix('../data/agaricus.txt.test')
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic' }
watchlist = [(dtest,'eval'), (dtrain,'train')]
param = {'max_depth':2, 'eta':1, 'silent':1, 'objective':'binary:logistic'}
watchlist = [(dtest, 'eval'), (dtrain, 'train')]
num_round = 3
bst = xgb.train(param, dtrain, num_round, watchlist)
@ -15,5 +15,5 @@ leafindex = bst.predict(dtest, ntree_limit=2, pred_leaf=True)
print(leafindex.shape)
print(leafindex)
### predict all trees
leafindex = bst.predict(dtest, pred_leaf = True)
leafindex = bst.predict(dtest, pred_leaf=True)
print(leafindex.shape)

6
demo/guide-python/sklearn_examples.py
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@ -20,7 +20,7 @@ y = digits['target']
X = digits['data']
kf = KFold(n_splits=2, shuffle=True, random_state=rng)
for train_index, test_index in kf.split(X):
xgb_model = xgb.XGBClassifier().fit(X[train_index],y[train_index])
xgb_model = xgb.XGBClassifier().fit(X[train_index], y[train_index])
predictions = xgb_model.predict(X[test_index])
actuals = y[test_index]
print(confusion_matrix(actuals, predictions))
@ -31,7 +31,7 @@ y = iris['target']
X = iris['data']
kf = KFold(n_splits=2, shuffle=True, random_state=rng)
for train_index, test_index in kf.split(X):
xgb_model = xgb.XGBClassifier().fit(X[train_index],y[train_index])
xgb_model = xgb.XGBClassifier().fit(X[train_index], y[train_index])
predictions = xgb_model.predict(X[test_index])
actuals = y[test_index]
print(confusion_matrix(actuals, predictions))
@ -42,7 +42,7 @@ y = boston['target']
X = boston['data']
kf = KFold(n_splits=2, shuffle=True, random_state=rng)
for train_index, test_index in kf.split(X):
xgb_model = xgb.XGBRegressor().fit(X[train_index],y[train_index])
xgb_model = xgb.XGBRegressor().fit(X[train_index], y[train_index])
predictions = xgb_model.predict(X[test_index])
actuals = y[test_index]
print(mean_squared_error(actuals, predictions))