I need to read a file in my train module into a np.array (i want to use the array as label_keys in a DNNClassifier).
I tried tf.read_file and tf.TextLineReader() but i can´t get them to just output the rows to a np.array.
Is it possible?
(why not just read a file with open? I´m training in GCS and want to get the file from storage :)
To access a file from GCS using TensorFlow, you can use the Python tf.gfile.GFile API, which acts like a regular Python file object, but allows you to use TensorFlow's filesystem connectors:
with tf.gfile.GFile("gs://...") as f:
file_contents = f.read()
Related
I've tried looking for this and haven't had any meaningful results.
I have a keras model that has multi input and my data was getting too large for my pandas approach so I preprocessed it and saved it parquet file. I'm not sure how to open it with keras.
I looked up tf.datasets but I still cannot figure out how to read a parquet file that I can pass to my model.
Does anyone know how to use open parquet files? I can't seem to figure out how to do this in tensorflow and can't find anything related to it in keras.
You can probably keep your pandas approach, but you would have to breakdown your data into chunks.
If you have already broken it down to create your parquet file, you should be able to use the same method to have only a subset of your data opened in pandas at a time.
If you need to extract the data from your parquet file here's a link on how to create chunks of data for a pandas dataframe:
How to read a CSV file subset by subset with Pandas?
Once you have a chunk of data you can call model.fit on that chunk of data and then go on to the next chunk and call model.fit
You can look into TensorFlow I/O which is a collection of file systems and file formats that are not available in TensorFlow's built-in support. Here you can find functionalities such tfio.IODataset.from_parquet, and also tfio.IOTensor.from_parquet to work with the parquet file formats.
!pip install tensorflow_io -U -q
import tensorflow_io as tfio
df = pd.DataFrame({"data": tf.random.normal([20], 0, 1, tf.float32),
"label": np.random.randint(2, size=(20))})
df.to_parquet("df.parquet")
pd.read_parquet('/content/df.parquet')[:2]
data label
0 0.721347 1
1 -1.215225 1
ds = tfio.IODataset.from_parquet('/content/df.parquet')
ds
FYI, I think you should also consider using the feather format rather than the parquet file format, AFAIK, the parquet file can be really heavy to load and can slow down your training pipelines, whereas feather is comparatively fast (very fast).
I am new to both python and tensorflow.
I am trying to make a input pipeline for a generative adversarial network with input complex number data in .mat format and loaded it with loadmat() from scipy.io library. Now I am trying to prepare my data for giving input to my network and i tried from_tensor_slices(). But it can not be converted into tensor because of the headers in it. I looked up how to remove header from files by python and found some techniques that can be applied to .csv file but nothing on .mat files. How can I remove the header from .mat files? Also, the loadmat() function returns a list of dictionary I think. How can I extract the data from the file under such condition? Thank you.
Tensorflow seems to lack a reader for ".npy" files.
How can I read my data files into the new tensorflow.data.Dataset pipline?
My data doesn't fit in memory.
Each object is saved in a separate ".npy" file. each file contains 2 different ndarrays as features and a scalar as their label.
It is actually possible to read directly NPY files with TensorFlow instead of TFRecords. The key pieces are tf.data.FixedLengthRecordDataset and tf.io.decode_raw, along with a look at the documentation of the NPY format. For simplicity, let's suppose that a float32 NPY file containing an array with shape (N, K) is given, and you know the number of features K beforehand, as well as the fact that it is a float32 array. An NPY file is just a binary file with a small header and followed by the raw array data (object arrays are different, but we're considering numbers now). In short, you can find the size of this header with a function like this:
def npy_header_offset(npy_path):
with open(str(npy_path), 'rb') as f:
if f.read(6) != b'\x93NUMPY':
raise ValueError('Invalid NPY file.')
version_major, version_minor = f.read(2)
if version_major == 1:
header_len_size = 2
elif version_major == 2:
header_len_size = 4
else:
raise ValueError('Unknown NPY file version {}.{}.'.format(version_major, version_minor))
header_len = sum(b << (8 * i) for i, b in enumerate(f.read(header_len_size)))
header = f.read(header_len)
if not header.endswith(b'\n'):
raise ValueError('Invalid NPY file.')
return f.tell()
With this you can create a dataset like this:
import tensorflow as tf
npy_file = 'my_file.npy'
num_features = ...
dtype = tf.float32
header_offset = npy_header_offset(npy_file)
dataset = tf.data.FixedLengthRecordDataset([npy_file], num_features * dtype.size, header_bytes=header_offset)
Each element of this dataset contains a long string of bytes representing a single example. You can now decode it to obtain an actual array:
dataset = dataset.map(lambda s: tf.io.decode_raw(s, dtype))
The elements will have indeterminate shape, though, because TensorFlow does not keep track of the length of the strings. You can just enforce the shape since you know the number of features:
dataset = dataset.map(lambda s: tf.reshape(tf.io.decode_raw(s, dtype), (num_features,)))
Similarly, you can choose to perform this step after batching, or combine it in whatever way you feel like.
The limitation is that you had to know the number of features in advance. It is possible to extract it from the NumPy header, though, just a bit of a pain, and in any case very hardly from within TensorFlow, so the file names would need to be known in advance. Another limitation is that, as it is, the solution requires you to either use only one file per dataset or files that have the same header size, although if you know that all the arrays have the same size that should actually be the case.
Admittedly, if one considers this kind of approach it may just be better to have a pure binary file without headers, and either hard code the number of features or read them from a different source...
You can do it with tf.py_func, see the example here.
The parse function would simply decode the filename from bytes to string and call np.load.
Update: something like this:
def read_npy_file(item):
data = np.load(item.decode())
return data.astype(np.float32)
file_list = ['/foo/bar.npy', '/foo/baz.npy']
dataset = tf.data.Dataset.from_tensor_slices(file_list)
dataset = dataset.map(
lambda item: tuple(tf.py_func(read_npy_file, [item], [tf.float32,])))
Does your data fit into memory? If so, you can follow the instructions from the Consuming NumPy Arrays section of the docs:
Consuming NumPy arrays
If all of your input data fit in memory, the simplest way to create a Dataset from them is to convert them to tf.Tensor objects and use Dataset.from_tensor_slices().
# Load the training data into two NumPy arrays, for example using `np.load()`.
with np.load("/var/data/training_data.npy") as data:
features = data["features"]
labels = data["labels"]
# Assume that each row of `features` corresponds to the same row as `labels`.
assert features.shape[0] == labels.shape[0]
dataset = tf.data.Dataset.from_tensor_slices((features, labels))
In the case that the file doesn't fit into memory, it seems like the only recommended approach is to first convert the npy data into a TFRecord format, and then use the TFRecord data set format, which can be streamed without fully loading into memory.
Here is a post with some instructions.
FWIW, it seems crazy to me that TFRecord cannot be instantiated with a directory name or file name(s) of npy files directly, but it appears to be a limitation of plain Tensorflow.
If you can split the single large npy file into smaller files that each roughly represent one batch for training, then you could write a custom data generator in Keras that would yield only the data needed for the current batch.
In general, if your dataset cannot fit in memory, storing it as one single large npy file makes it very hard to work with, and preferably you should reformat the data first, either as TFRecord or as multiple npy files, and then use other methods.
Problem setup
I had a folder with images that were being fed into an InceptionV3 model for extraction of features. This seemed to be a huge bottleneck for the entire process. As a workaround, I extracted features from each image and then stored them on disk in a .npy format.
Now I had two folders, one for the images and one for the corresponding .npy files. There was an evident problem with the loading of .npy files in the tf.data.Dataset pipeline.
Workaround
I came across TensorFlow's official tutorial on show attend and tell which had a great workaround for the problem this thread (and I) were having.
Load numpy files
First off we need to create a mapping function that accepts the .npy file name and returns the numpy array.
# Load the numpy files
def map_func(feature_path):
feature = np.load(feature_path)
return feature
Use the tf.numpy_function
With the tf.numpy_function we can wrap any python function and use it as a TensorFlow op. The function must accept numpy object (which is exactly what we want).
We create a tf.data.Dataset with the list of all the .npy filenames.
dataset = tf.data.Dataset.from_tensor_slices(feature_paths)
We then use the map function of the tf.data.Dataset API to do the rest of our task.
# Use map to load the numpy files in parallel
dataset = dataset.map(lambda item: tf.numpy_function(
map_func, [item], tf.float16),
num_parallel_calls=tf.data.AUTOTUNE)
Google recently announced the Clould ML, https://cloud.google.com/ml/ and it's very useful. However, one limitation is that the input/out of a Tensorflow program should support gs://.
If we use all tensorflow APIS to read/write files, it should OK, since these APIs support gs://.
However, if we use native file IO APIs such as open, it does not work, because they don't understand gs://
For example:
with open(vocab_file, 'wb') as f:
cPickle.dump(self.words, f)
This code won't work in Google Cloud ML.
However, modifying all native file IO APIs to tensorflow APIs or Google Storage Python APIs is really tedious. Is there any simple way to do this? Any wrappers to support google storage systems, gs:// on top of the native file IO?
As suggested here Pickled scipy sparse matrix as input data?, perhaps we can use file_io.read_file_to_string('gs://...'), but still this requrements significant code modifcation.
Do it like this:
from tensorflow.python.lib.io import file_io
with file_io.FileIO('gs://.....', mode='w+') as f:
cPickle.dump(self.words, f)
Or you can read pickle file in like this:
file_stream = file_io.FileIO(train_file, mode='r')
x_train, y_train, x_test, y_test = pickle.load(file_stream)
One solution is to copy all of the data to local disk when the program starts up. You can do that using gsutil inside the Python script that gets run, something like:
vocab_file = 'vocab.pickled'
subprocess.check_call(['gsutil', '-m' , 'cp', '-r',
os.path.join('gs://path/to/', vocab_file), '/tmp'])
with open(os.path.join('/tmp', vocab_file), 'wb') as f:
cPickle.dump(self.words, f)
And if you have any outputs, you can write them to local disk and gsutil rsync them. (But, be careful to handle restarts correctly, because you may be put on a different machine).
The other solution is to monkey patch open (Note: untested):
import __builtin__
# NB: not all modes are compatible; should handle more carefully.
# Probably should be reported on
# https://github.com/tensorflow/tensorflow/issues/4357
def new_open(name, mode='r', buffering=-1):
return file_io.FileIO(name, mode)
__builtin__.open = new_open
Just be sure to do that before any module actually tries to read from GCS.
apache_beam has the gcsio module which can be used to return a standard Python file object to read/write GCS objects. You can use this object with any method that works with Python file objects. For example
def open_local_or_gcs(path, mode):
"""Opens the given path."""
if path.startswith('gs://'):
try:
return gcsio.GcsIO().open(path, mode)
except Exception as e: # pylint: disable=broad-except
# Currently we retry exactly once, to work around flaky gcs calls.
logging.error('Retrying after exception reading gcs file: %s', e)
time.sleep(10)
return gcsio.GcsIO().open(path, mode)
else:
return open(path, mode)
with open_local_or_gcs(vocab_file, 'wb') as f:
cPickle.dump(self.words, f)
After following this tutorial on summaries and TensorBoard, I've been able to successfully save and look at data with TensorBoard. Is it possible to open this data with something other than TensorBoard?
By the way, my application is to do off-policy learning. I'm currently saving each state-action-reward tuple using SummaryWriter. I know I could manually store/train on this data, but I thought it'd be nice to use TensorFlow's built in logging features to store/load this data.
As of March 2017, the EventAccumulator tool has been moved from Tensorflow core to the Tensorboard Backend. You can still use it to extract data from Tensorboard log files as follows:
from tensorboard.backend.event_processing.event_accumulator import EventAccumulator
event_acc = EventAccumulator('/path/to/summary/folder')
event_acc.Reload()
# Show all tags in the log file
print(event_acc.Tags())
# E. g. get wall clock, number of steps and value for a scalar 'Accuracy'
w_times, step_nums, vals = zip(*event_acc.Scalars('Accuracy'))
Easy, the data can actually be exported to a .csv file within TensorBoard under the Events tab, which can e.g. be loaded in a Pandas dataframe in Python. Make sure you check the Data download links box.
For a more automated approach, check out the TensorBoard readme:
If you'd like to export data to visualize elsewhere (e.g. iPython
Notebook), that's possible too. You can directly depend on the
underlying classes that TensorBoard uses for loading data:
python/summary/event_accumulator.py (for loading data from a single
run) or python/summary/event_multiplexer.py (for loading data from
multiple runs, and keeping it organized). These classes load groups of
event files, discard data that was "orphaned" by TensorFlow crashes,
and organize the data by tag.
As another option, there is a script
(tensorboard/scripts/serialize_tensorboard.py) which will load a
logdir just like TensorBoard does, but write all of the data out to
disk as json instead of starting a server. This script is setup to
make "fake TensorBoard backends" for testing, so it is a bit rough
around the edges.
I think the data are encoded protobufs RecordReader format. To get serialized strings out of files you can use py_record_reader or build a graph with TFRecordReader op, and to deserialize those strings to protobuf use Event schema. If you get a working example, please update this q, since we seem to be missing documentation on this.
I did something along these lines for a previous project. As mentioned by others, the main ingredient is tensorflows event accumulator
from tensorflow.python.summary import event_accumulator as ea
acc = ea.EventAccumulator("folder/containing/summaries/")
acc.Reload()
# Print tags of contained entities, use these names to retrieve entities as below
print(acc.Tags())
# E. g. get all values and steps of a scalar called 'l2_loss'
xy_l2_loss = [(s.step, s.value) for s in acc.Scalars('l2_loss')]
# Retrieve images, e. g. first labeled as 'generator'
img = acc.Images('generator/image/0')
with open('img_{}.png'.format(img.step), 'wb') as f:
f.write(img.encoded_image_string)
You can also use the tf.train.summaryiterator: To extract events in a ./logs-Folder where only classic scalars lr, acc, loss, val_acc and val_loss are present you can use this GIST: tensorboard_to_csv.py
Chris Cundy's answer works well when you have less than 10000 data points in your tfevent file. However, when you have a large file with over 10000 data points, Tensorboard will automatically sampling them and only gives you at most 10000 points. It is a quite annoying underlying behavior as it is not well-documented. See https://github.com/tensorflow/tensorboard/blob/master/tensorboard/backend/event_processing/event_accumulator.py#L186.
To get around it and get all data points, a bit hacky way is to:
from tensorboard.backend.event_processing.event_accumulator import EventAccumulator
class FalseDict(object):
def __getitem__(self,key):
return 0
def __contains__(self, key):
return True
event_acc = EventAccumulator('path/to/your/tfevents',size_guidance=FalseDict())
It looks like for tb version >=2.3 you can streamline the process of converting your tb events to a pandas dataframe using tensorboard.data.experimental.ExperimentFromDev().
It requires you to upload your logs to TensorBoard.dev, though, which is public. There are plans to expand the capability to locally stored logs in the future.
https://www.tensorflow.org/tensorboard/dataframe_api
You can also use the EventFileLoader to iterate through a tensorboard file
from tensorboard.backend.event_processing.event_file_loader import EventFileLoader
for event in EventFileLoader('path/to/events.out.tfevents.xxx').Load():
print(event)
Surprisingly, the python package tb_parse has not been mentioned yet.
From documentation:
Installation:
pip install tensorflow # or tensorflow-cpu pip install -U tbparse # requires Python >= 3.7
Note: If you don't want to install TensorFlow, see Installing without TensorFlow.
We suggest using an additional virtual environment for parsing and plotting the tensorboard events. So no worries if your training code uses Python 3.6 or older versions.
Reading one or more event files with tbparse only requires 5 lines of code:
from tbparse import SummaryReader
log_dir = "<PATH_TO_EVENT_FILE_OR_DIRECTORY>"
reader = SummaryReader(log_dir)
df = reader.scalars
print(df)