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KICKSTART YOUR PYTHON PROJECT

Part 1: Coockiecutter, git and virtualenv

Cookiecutter

Install cookiecutter in your system/user python profile (not a virtual environment).
```
$ pip install --user cookiecutter
```
Surf the file system until your code folder (e.g. path/to/repos_folder). This is the parent folder of your code. NB: cookiecutter will create a new folder project_name with everything inside. Your actual code will be in a subfolder, i.e. path/to/repos_folder/project_name/src/ Then run cookiecutter with the link to the data-science-template and prompt the question it will ask you:
```
$ cd Documents/xxx/xxx/Code/
$ cookiecutter https://github.com/drivendata/cookiecutter-data-science
# fill the question using project name: kickstart_python
# once it is finished, cd the forder kickstart_python
$ cd kickstart_python
```
From now on, our current directory will be path/to/kickstarn_python/ unless specified

Virtual Environment pt1

set up a virtual environment, named venv, specifying the python version. venv is a typical convention, you could call it remi if you want. This code will create a folder named venv containing lot of things and a local copy of all the packages you will pip-install from now on.
```
$ virtualenv venv -p python3
```
edit the .gitignore by adding the virtualenv's folder with you favorite text editor or just run the following command
```
$ echo venv >> .gitignore
```

GIT

set up git and link it to a new github/gitlab reporitory:

On github.com create an empty reporitory online (it means no README and no license. If you do so it will display usefull command).
Start git locally and synch it with the following commands:

$ git init
# check we are not 'saving' wried files
$ git status
# if so, commit
$ git add .
$ git commit -m "first commit"

# If github
$ git remote add origin https://github.com/USER/python_kickstart.git

$ git push -u origin master
# avoid writing login and password for the future time
$ git config credential.helper store

Virtual Environment pt2

Activate the virtualenv

[user@localhost] project_name/ $ source venv/bin/activate
# check that it is activated. You should have (venv) at the beginnig of your command line
(venv) [user@localhost] project_name/ $

Install the basic dependencies of cookiecutter (if you want). Notice that doing so also you will install the src package by default. Then install your everyday-coding-favorite-life packages: numpy, matplotlib, jupyter
```
(venv) $ pip install -r requirements.txt
(venv) $ pip install numpy matplotlib jupyter
```
Freeze the requirements ('>' overwrite, '>>' append)
```
(venv) $ pip freeze >> requirements.txt
```
Install the package for a toy example
```
(venv) $ pip install sklearn
```

in src/ create the main.py file and paste the following code:

from numpy.random import permutation
from sklearn import svm, datasets

C = 1.0
gamma = 0.7
iris = datasets.load_iris()
perm = permutation(iris.target.size)
iris.data = iris.data[perm]
iris.target = iris.target[perm]
model = svm.SVC(C, 'rbf', gamma=gamma)
model.fit(iris.data[:90],
        iris.target[:90])
print(model.score(iris.data[90:],
                iris.target[90:]))

commit the changes
```
$ git add .
$ git commit -m 'toy svm'
```

edit the models/train_model.py and models/predict_model.py files. I In both of the files (actually python modules) create new function respectively In ./src/models/train_model.py:

from sklearn import svm
def train(data, target, C, gamma):
    clf = svm.SVC(C, 'rbf', gamma=gamma)
    clf.fit(data[:90],
            target[:90])
    return clf

In ./src/models/predict_model.py:

def predict(clf, data, target):
    return clf.score(data, target)

Update the main file in order to import with the following imports In src/main.py add:

from models.predict_model import predict
from models.train_model import train

Now The main code should looks like:

# std imports
from numpy.random import permutation
from sklearn import datasets
# my imports
from models.predict_model import predict
from models.train_model import train

C = 1.0
gamma = 0.7
iris = datasets.load_iris()
per = permutation(iris.target.size)
iris.data = iris.data[per]
iris.target = iris.target[per]
model = train(iris.data[:90], iris.target[:90], C, gamma)
score = predict(model, iris.data[90:], iris.target[90:])
print(score)

Run and debug
```
(venv) $ python src/main.py
```

Sacred

PIP-install Sacred for tracking experiments
```
(venv) $ pip install sacred pymongo
```

create a new function for the parameters C and gamma and add the colorators for Sacred

#...add here the new nice imports and add the followings
from sacred import Experiment
ex = Experiment('iris_svm') # id of the experiments

@ex.config
def cfg():
    C = 1.0
    gamma = 0.7

@ex.automain
def run(C, gamma):
    # ...
    # ... paste here the main
    #...
    return score

run it from the project's root directory
```
(venv) $ python src/main.py
```

MongoDB and Omniboard

install mongodb in your system. In a new terminal

$ sudo dnf install mongodb mongodb-server mongoose
# start service
$ sudo service mongod start
# verify it is woring
$ mongo  # it will start the mongo-db-shell

Run and re-run as many time as you want the code with the database flag:
```
(venv) $ python src/main.py -m MY_IRIS_EXP
```
notice how the ID value increase at each run
In a mongo shell (just run mongo in the command line) check if the MY_IRIS_EXP database exists
```
$ mongo
# after in the mongo shell
> show dbs
# look for MY_IRIS_EXP entry
```
download and install Ominboard, the sacred+mongo frontends
```
# in a new terminal
$ sudo npm install -g omniboard
```

In the same shell run the server listener

$ omniboard -m localhost:27017:MY_IRIS_EXP

go to http://localhost:9000 to access omniboard frontends:
play with it

Experiment metrics and omniboard visualization

add a metric in the main.py file add

@ex.automain
def run(C, gamma):
    ... # the code before
    ex.log_scalar("val.score", score)
    return score

And what about a typical loss fuction in a for loop? for instance add the following line. We need to pass the object _run at the main()

@ex.automain
def run(_run, C, gamma):
    ... # the code before
    my_loss = 0
    for i in range(20):
        # Explicit step counter (0, 1, 2, 3, ...)
        # incremented with each call for training.accuracy:
        _run.log_scalar("training.loss", my_loss, i)
        my_loss += 1.5*i + np.random.random(1)
    return score

run some experiments
play in omniboard

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