/
data_utils.py
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/
data_utils.py
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"""### Data Tools
Functions for dealing with datasets. These are not importable from
the top level `energyflow` module, but must instead be imported
from `energyflow.utils`.
"""
from __future__ import absolute_import, division, print_function
import hashlib
import os
import sys
import numpy as np
from six.moves.urllib.error import HTTPError, URLError
from energyflow.utils.generic_utils import ALL_EXAMPLES
__all__ = [
'get_examples',
'data_split',
'to_categorical',
'remap_pids'
]
def get_examples(path='~/.energyflow', which='all', overwrite=False):
"""Pulls examples from GitHub. To ensure availability of all examples
update EnergyFlow to the latest version.
**Arguments**
- **path** : _str_
- The destination for the downloaded files. Note that `examples`
is automatically appended to the end of this path.
- **which** : {_list_, `'all'`}
- List of examples to download, or the string `'all'` in which
case all the available examples are downloaded.
- **overwrite** : _bool_
- Whether to overwrite existing files or not.
"""
# all current examples
all_examples = set(ALL_EXAMPLES)
# process which examples are selected
if which == 'all':
examples = all_examples
else:
if not isinstance(which, (tuple, list)):
which = [which]
examples = all_examples.intersection(which)
base_url = 'https://github.com/pkomiske/EnergyFlow/raw/master/examples/'
cache_dir = os.path.expanduser(path)
# get each example
files = []
for example in examples:
# remove file if necessary
file_path = os.path.join(cache_dir, 'examples', example)
if overwrite and os.path.exists(file_path):
os.remove(file_path)
files.append(_get_filepath(example, base_url+example, cache_dir, cache_subdir='examples'))
# print summary
print()
print('Summary of examples:')
for f in files:
path, fname = os.path.split(f)
print(fname, 'exists at', path)
print()
# data_split(*args, train=-1, val=0.0, test=0.1, shuffle=True)
def data_split(*args, **kwargs):
"""A function to split a dataset into train, test, and optionally
validation datasets.
**Arguments**
- ***args** : arbitrary _numpy.ndarray_ datasets
- An arbitrary number of datasets, each required to have
the same number of elements, as numpy arrays.
- **train** : {_int_, _float_}
- If a float, the fraction of elements to include in the training
set. If an integer, the number of elements to include in the
training set. The value `-1` is special and means include the
remaining part of the dataset in the training dataset after
the test and (optionally) val parts have been removed
- **val** : {_int_, _float_}
- If a float, the fraction of elements to include in the validation
set. If an integer, the number of elements to include in the
validation set. The value `0` is special and means do not form
a validation set.
- **test** : {_int_, _float_}
- If a float, the fraction of elements to include in the test
set. If an integer, the number of elements to include in the
test set.
- **shuffle** : _bool_
- A flag to control whether the dataset is shuffled prior to
being split into parts.
**Returns**
- _list_
- A list of the split datasets in train, [val], test order. If
datasets `X`, `Y`, and `Z` were given as `args` (and assuming a
non-zero `val`), then [`X_train`, `X_val`, `X_test`, `Y_train`,
`Y_val`, `Y_test`, `Z_train`, `Z_val`, `Z_test`] will be returned.
"""
# handle valid kwargs
train, val, test = kwargs.pop('train', -1), kwargs.pop('val', 0.0), kwargs.pop('test', 0.1)
shuffle = kwargs.pop('shuffle', True)
if len(kwargs):
raise TypeError('following kwargs are invalid: {}'.format(kwargs))
# validity checks
if len(args) == 0:
raise RuntimeError('Need to pass at least one argument to data_split')
# check for consistent length
n_samples = len(args[0])
for arg in args[1:]:
assert len(arg) == n_samples, 'args to data_split have different length'
# determine numbers
num_val = int(n_samples*val) if val<=1 else val
num_test = int(n_samples*test) if test <=1 else test
num_train = n_samples - num_val - num_test if train==-1 else (int(n_samples*train) if train<=1 else train)
assert num_train >= 0, 'bad parameters: negative num_train'
assert num_train + num_val + num_test <= n_samples, 'too few samples for requested data split'
# calculate masks
perm = np.random.permutation(n_samples) if shuffle else np.arange(n_samples)
train_mask = perm[:num_train]
val_mask = perm[-num_val:]
test_mask = perm[num_train:num_train+num_test]
# apply masks
masks = [train_mask, val_mask, test_mask] if num_val > 0 else [train_mask, test_mask]
# return list of new datasets
return [arg[mask] for arg in args for mask in masks]
def to_categorical(labels, num_classes=None):
"""One-hot encodes class labels.
**Arguments**
- **labels** : _1-d numpy.ndarray_
- Labels in the range `[0,num_classes)`.
- **num_classes** : {_int_, `None`}
- The total number of classes. If `None`, taken to be the
maximum label plus one.
**Returns**
- _2-d numpy.ndarray_
- The one-hot encoded labels.
"""
# get num_classes from max label if None
if num_classes is None:
num_classes = np.int(np.max(labels)) + 1
y = np.asarray(labels, dtype=int)
n = y.shape[0]
categorical = np.zeros((n, num_classes))
# index into array and set appropriate values to 1
categorical[np.arange(n), y] = 1
return categorical
# PDGid to small float dictionary
pid2float_mapping = {22: 0,
211: .1, -211: .2,
321: .3, -321: .4,
130: .5,
2112: .6, -2112: .7,
2212: .8, -2212: .9,
11: 1.0, -11: 1.1,
13: 1.2, -13: 1.3}
def remap_pids(events, pid_i=3):
"""Remaps PDG id numbers to small floats for use in a neural network.
`events` are modified in place and nothing is returned.
**Arguments**
- **events** : _3-d numpy.ndarray_
- The events as an array of arrays of particles.
- **pid_i** : _int_
- The index corresponding to pid information along the last
axis of `events`.
"""
events_shape = events.shape
pids = events[:,:,pid_i].astype(int).reshape((events_shape[0]*events_shape[1]))
events[:,:,pid_i] = np.asarray([pid2float_mapping.get(pid, 0) for pid in pids]).reshape(events_shape[:2])
# the following code is closely based on analogous parts of Keras
if sys.version_info[0] == 2:
from contextlib import closing
from six.moves.urllib.request import urlopen
def urlretrieve(url, filename, reporthook=None, data=None):
"""Replacement for `urlretrive` for Python 2.
Under Python 2, `urlretrieve` relies on `FancyURLopener` from legacy
`urllib` module, known to have issues with proxy management.
# Arguments
url: url to retrieve.
filename: where to store the retrieved data locally.
reporthook: a hook function that will be called once
on establishment of the network connection and once
after each block read thereafter.
The hook will be passed three arguments;
a count of blocks transferred so far,
a block size in bytes, and the total size of the file.
data: `data` argument passed to `urlopen`.
"""
def chunk_read(response, chunk_size=8192, reporthook=None):
content_type = response.info().get('Content-Length')
total_size = -1
if content_type is not None:
total_size = int(content_type.strip())
count = 0
while True:
chunk = response.read(chunk_size)
count += 1
if reporthook is not None:
reporthook(count, chunk_size, total_size)
if chunk:
yield chunk
else:
break
with closing(urlopen(url, data)) as response, open(filename, 'wb') as fd:
for chunk in chunk_read(response, reporthook=reporthook):
fd.write(chunk)
else:
from six.moves.urllib.request import urlretrieve
def _pad_events_axis1(events, axis1_shape):
"""Pads the first axis of the NumPy array `events` with zero subarrays
such that the first dimension of the results has size `axis1_shape`.
"""
num_zeros = axis1_shape - events.shape[1]
if num_zeros > 0:
zeros = np.zeros([num_zeros if i == 1 else s for i,s in enumerate(events.shape)])
return np.concatenate((events, zeros), axis=1)
return events
def _hash_file(fpath, algorithm='sha256', chunk_size=131071):
"""Calculates a file sha256 or md5 hash.
# Example
```python
>>> from keras.data_utils import _hash_file
>>> _hash_file('/path/to/file.zip')
'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855'
```
# Arguments
fpath: path to the file being validated
algorithm: hash algorithm, one of 'auto', 'sha256', or 'md5'.
The default 'auto' detects the hash algorithm in use.
chunk_size: Bytes to read at a time, important for large files.
# Returns
The file hash
"""
if (algorithm == 'sha256') or (algorithm == 'auto'):
hasher = hashlib.sha256()
else:
hasher = hashlib.md5()
with open(fpath, 'rb') as fpath_file:
for chunk in iter(lambda: fpath_file.read(chunk_size), b''):
hasher.update(chunk)
return hasher.hexdigest()
def _validate_file(fpath, file_hash, algorithm='auto', chunk_size=131071):
"""Validates a file against a sha256 or md5 hash.
# Arguments
fpath: path to the file being validated
file_hash: The expected hash string of the file.
The sha256 and md5 hash algorithms are both supported.
algorithm: Hash algorithm, one of 'auto', 'sha256', or 'md5'.
The default 'auto' detects the hash algorithm in use.
chunk_size: Bytes to read at a time, important for large files.
# Returns
Whether the file is valid
"""
if ((algorithm == 'sha256') or (algorithm == 'auto' and len(file_hash) == 64)):
hasher = 'sha256'
else:
hasher = 'md5'
return str(_hash_file(fpath, hasher, chunk_size)) == str(file_hash)
def _get_filepath(filename, url, cache_dir, cache_subdir='datasets', file_hash=None):
"""Pulls file from the internet."""
# handle '~' in path
datadir_base = os.path.expanduser(cache_dir)
# ensure that directory exists
datadir = os.path.join(datadir_base, cache_subdir)
if not os.path.exists(datadir):
os.makedirs(datadir)
# handle case where cache is not writeable
if not os.access(datadir_base, os.W_OK):
datadir = os.path.join('/tmp', '.energyflow', cache_subdir)
if not os.path.exists(datadir):
os.makedirs(datadir)
fpath = os.path.join(datadir, filename)
# determine if file needs to be downloaded
download = False
if os.path.exists(fpath):
if file_hash is not None and not _validate_file(fpath, file_hash):
print('Local file hash does not match so we will redownload...')
download = True
else:
download = True
if download:
print('Downloading {} from {} to {}'.format(filename, url, datadir))
error_msg = 'URL fetch failure on {}: {} -- {}'
try:
try:
urlretrieve(url, fpath)
except URLError as e:
raise Exception(error_msg.format(url, e.errno, e.reason))
except HTTPError as e:
raise Exception(error_msg.format(url, e.code, e.msg))
except (Exception, KeyboardInterrupt):
if os.path.exists(fpath):
os.remove(fpath)
raise
if file_hash is not None:
assert _validate_file(fpath, file_hash), 'Hash of downloaded file incorrect.'
return fpath