macOS 10.15 to install tensorflow 2.4 for python

Tensorflow is a popular framework for machine learning.

The latest version tensorflow 2 runs on python 3.

My default python version in OSX is  2.7.18

To avoid messing the system, I am going to install tensorflow in a python virtual environment.

* * * * * 

# get the latest python 3

$ brew install python3       # or 

$ brew upgrade python3

# mine installed to  /usr/local/opt/python@3.9@ -> ../Cellar/python@3.9/3.9.2_1

# upgrade pip

/usr/local/opt/python@3.9/bin/python3.9 -m pip install --upgrade pip

(pls refer to official doc for installing virtualenv)

# upgrade virtualenv

/usr/local/opt/python@3.9/bin/python3.9 -m pip install --upgrade virtualenv

# if permission error, append '-user' option to the end

/usr/local/opt/python@3.9/bin/python3.9 -m pip install --upgrade virtualenv -user

# also upgrade the wrapper

/usr/local/opt/python@3.9/bin/python3.9 -m pip install --upgrade virtualenvwrapper

# create new virtual environment

mkvirtualenv -p python3 tf

# enter venv

workon tf

# upgrade pip

~/.virtualenvs/tf/bin/python -m pip install --upgrade pip

# install tensorflow

$ ~/.virtualenvs/tf/bin/python -m pip install tensorflow

# launch python; note version 3.x will be in greeting text

$ python

# check tensorflow installation successful

>>> import tensorflow as tf

>>> tf.__version__

'2.4.1'

# first tensorflow (v1) program

>>> import tensorflow.compat.v1 as tf

>>> tf.disable_v2_behavior()

>>> a = tf.constant(1, name='a')

>>> b = tf.constant(1, name='b')

>>> c = a + b

>>> with tf.compat.v1.Session() as sess:

...     print(sess.run(c))

... 

2021-03-07 12:05:15.104500: I tensorflow/compiler/jit/xla_cpu_device.cc:41] Not creating XLA devices, tf_xla_enable_xla_devices not set

2021-03-07 12:05:15.106227: I tensorflow/compiler/mlir/mlir_graph_optimization_pass.cc:196] None of the MLIR optimization passes are enabled (registered 0 passes)

2

>>>

a, b, and c are objects

>>> print(a)

Tensor("a:0", shape=(), dtype=int32)

when done, 

ctrl+d to quit python

then deactivate venv

$ deactivate