#!/usr/bin/env python
# coding: utf-8

# ## Using Jupyter/IPython for Teaching
# 
# <p xmlns:dct="http://purl.org/dc/terms/">
#   <a rel="license"
#      href="http://creativecommons.org/publicdomain/zero/1.0/">
#     <img src="http://i.creativecommons.org/p/zero/1.0/88x31.png" style="border-style: none;" alt="CC0" />
#   </a>
# </p>

# This notebook is meant to be a slide show.
# If it doesn't look like a slide show, you probably have to install [RISE](https://github.com/damianavila/RISE/):
# 
#     python3 -m pip install rise --user
#     python3 -m notebook.nbextensions install --python rise --user
#     python3 -m notebook.nbextensions enable --python rise --user
# 
# If it doesn't work, you might have to use `python` instead of `python3`.
# 
# After the installation (and after re-loading the Jupyter notebook), you will have a new item in the toolbar which allows you to start the presentation.

# ### What is Jupyter?
# 
# * formerly known as *IPython* ("interactive Python")
# * an interactive terminal and a browser-based notebook
# * https://jupyter.org/

# * can be used with different programming languages:
# 
#   * **Ju**lia (http://julialang.org/)
#   
#   * **Pyt**hon (https://www.python.org/)
#   
#   * **R** (http://www.r-project.org/)
#   
#   * and many others ...

# ### What's so great about the Jupyter notebook?
# 
# * mix of text, code and results
# 
# * media
# 
#   * images, audio, video
#   
#   * anything a web browser can display
# 
# * equations

# ### One notebook, many uses
# 
# * interactive local use
# 
# * static online HTML pages on http://nbviewer.jupyter.org/
# 
# * interactive online use at https://mybinder.org/
# 
# * nbconvert
# 
#   * HTML
#   
#   * $\mathrm{\LaTeX}$ $\to$ PDF
#   
#   * `.py` files
#   
#   * ...
# 
# * slide shows!

# ### HTML5 `<audio>` tag
# 
# <audio src="data/singing.wav" controls>Your browser does not support the audio element.</audio>
# ![CC BY-SA](data/by-sa.png)[singing.wav](data/singing.wav) by [www.openairlib.net](http://www.openairlib.net/anechoicdb/content/operatic-voice); [CC BY-SA](http://creativecommons.org/licenses/by-sa/3.0/).
# 

# ### Loading Audio Data in Python

# In[1]:


import soundfile as sf
sig, fs = sf.read('data/singing.wav')


# ### Plotting

# In[2]:


get_ipython().run_line_magic('matplotlib', 'inline')
import matplotlib.pyplot as plt


# In[3]:


import numpy as np


# In[4]:


t = np.arange(len(sig)) / fs
plt.plot(t, sig)
plt.xlabel('time / seconds')
plt.grid()


# ### Spectrogram

# Squared magnitude of the Short Time Fourier Transform (STFT)
# 
# $$|\text{STFT}\{x[n]\}(m, \omega)|^2 = \left| \sum_{n=-\infty}^\infty x[n]w[n-m] \text{e}^{-j \omega n}\right|^2$$

# In[5]:


plt.specgram(sig, Fs=fs)
plt.ylabel('frequency / Hz')
plt.xlabel('time / seconds')
plt.ylim(0, 10000);


# ## Symbolic Math

# In[6]:


get_ipython().run_line_magic('matplotlib', 'inline')
import sympy as sp

sp.init_printing()

t, sigma, omega = sp.symbols(('t', 'sigma', 'omega'))

sigma = -2
omega = 10
s = sigma + sp.I * omega
x = sp.exp(s * t)
x


# In[7]:


sp.plotting.plot(sp.re(x),(t, 0, 2 * sp.pi), ylim=[-2, 2], ylabel='Re{$e^{st}$}')
sp.plotting.plot(sp.im(x),(t, 0, 2 * sp.pi), ylim=[-2, 2], ylabel='Im{$e^{st}$}');


# ## Example notebooks
# 
# [exercises for the lecture "communication acoustics"](http://nbviewer.ipython.org/github/spatialaudio/communication-acoustics-exercises/blob/master/index.ipynb)

# That's it for now!

# <p xmlns:dct="http://purl.org/dc/terms/">
#   <a rel="license"
#      href="http://creativecommons.org/publicdomain/zero/1.0/">
#     <img src="http://i.creativecommons.org/p/zero/1.0/88x31.png" style="border-style: none;" alt="CC0" />
#   </a>
#   <br />
#   To the extent possible under law,
#   <span rel="dct:publisher" resource="[_:publisher]">the person who associated CC0</span>
#   with this work has waived all copyright and related or neighboring
#   rights to this work.
# </p>