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

# ## Lecture for the course [Python for MATLAB users](http://sese.nu/python-for-matlab-users/), by Olivier Verdier

# We begin by importing scientific packages in the global namespace:

# In[2]:


get_ipython().run_line_magic('pylab', '')


# We tell `matplotlib` to plot inside this notebook.

# In[3]:


get_ipython().run_line_magic('matplotlib', 'inline')


# ## Notebook

# Shift+enter, help, save, `%whos`, `%pylab`, `%debug`, text+Python, up-downloadable, [Python notebook for matlab users](http://xcorr.net/2013/04/19/ipython-and-ipython-notebook-for-matlab-users/), [Nature article](http://www.nature.com/news/interactive-notebooks-sharing-the-code-1.16261), nonlinear evaluation

# In[4]:


a = 3
b = 10


# ## Basic types

# * Integers
# * Floats
# * Complex (conjugate, real(), imag(), .real, .imag)
# 
# Operations (`*`,`+`,`-`,`**`,`/`), and `//`. Operations `%`, `int`?

# In[5]:


i = 3


# In[8]:


print(i)


# In[7]:


i


# In[9]:


Out[7] + 10


# In[10]:


type(i)


# In[14]:


get_ipython().run_line_magic('whos', '')


# In[15]:


f = 2.3


# In[16]:


type(f)


# In[17]:


f + i


# In[18]:


print(type(1))
print(type(1.))


# In[19]:


z = 1. + 2.j


# In[20]:


print(z)


# In[21]:


J = 1.j


# In[22]:


2 + 3*J


# In[24]:


type(2+3j)


# In[25]:


z


# In[27]:


z.real


# In[28]:


z.imag


# In[30]:


z.conjugate()


# In[31]:


get_ipython().run_line_magic('whos', '')


# In[32]:


f * i


# In[33]:


f + i


# In[34]:


2^3


# In[35]:


2**3


# In[36]:


2/3


# In[37]:


2//3


# In[38]:


10//4


# In[42]:


print(10.1//4.1)
print(floor(10.1/4.1))


# In[43]:


# comment


# In[ ]:





# In[ ]:





# In[ ]:





# In[44]:


pi


# ## Strings

# Double, single quotes, triple, escape (`\`), concatenation (`+`), interpolation (`%`, `format`)

# In[49]:


s = "hello " 


# In[50]:


me = "Olivier"


# In[51]:


s + me


# In[60]:


template = "Hello {}, my name is {}"


# In[61]:


template.format("Olivier", "Jupyter")


# In[ ]:





# In[54]:


template.format("Åsa")


# In[55]:


s_ = 'single quotes instead'


# In[56]:


s__ = "I'm happy"


# In[58]:


print(s)
print(s__)


# In[ ]:


s = """Three quotes
with return inside
another one
"""


# In[63]:


s = "hello, \nI'm happy"
print(s)


# In[ ]:





# ## Functions

# `def`, name, parameters, colon `:`, *indentation block*, `return`, execution with `()`, pass function around

# In[67]:


def my_function(param):
    print(param)
    return 3


# In[68]:


a = my_function("argument")


# In[69]:


a


# In[78]:


def add_prod(x1, x2):
    """This is a nice function,
    which computes add and product of
    two numbers"""
    return x1 + x2, x1*x2


# In[79]:


get_ipython().run_line_magic('pinfo', 'add_prod')


# In[74]:


r = add_prod(2,3)


# In[75]:


print(r)


# In[76]:


r[0]


# In[77]:


r[1]


# In[ ]:





# In[73]:


print(s,p)


# In[ ]:





# In[ ]:





# In[104]:


def greetings(name):
    template = "Hello {}, how are you??"
    print(template)
    print("still in function")
    

print("I'm outside the function")


# In[86]:


greetings(3)


# In[88]:


def print_greetings():
    print("Hi!")


# In[96]:


def compute():
    x = 2 + 5
    return x


# In[97]:


def post_process(x):
    return x + 10


# In[98]:


post_process(compute())


# In[ ]:





# In[99]:


x = print_greetings


# In[100]:


print(x)


# In[101]:


x()


# In[ ]:





# In[89]:


print_greetings() # function execution


# In[90]:


print_greetings # just the function


# In[102]:


def execute(f):
    f()


# In[103]:


execute(print_greetings)


# In[ ]:





# In[ ]:


x = print_greetings


# In[ ]:


x()


# In[ ]:


def get_number():
    return 2.


# In[ ]:


y = get_number
y + 2


# In[ ]:


"2" + 3


# In[ ]:


2. + 3


# In[ ]:


x = 2.


# In[ ]:


x.__add__(3)


# ## If Statements

# step function (plot+`vectorize`?), comparison ops `==`, `!=`, `<`, `>`, `<=`, `>=`. Logical ops `not`, `and`, `or`, `bool`

# In[108]:


def sign(x):
    if x > 0:
        # several instructions here
        return 1.
    elif x > -1:
        return 0.
    else:
        return -1


# In[ ]:





# In[110]:


def inside(x):
    if (x < 0) and (x > -1):
        return "fantastic"
    else:
        return "too bad"


# In[112]:


inside(-.5)


# In[113]:


2 > 3 or 10 > 5


# In[114]:


not 3 < 5


# In[ ]:





# In[109]:


sign(-.5)


# In[106]:


sign(3)


# In[107]:


sign(-1)


# In[ ]:





# ## Lists

# `[]`, accessing (from zero!), altering, `append`, `len`, concatenate `+`, and `*`, slicing `:`, last element `-1`

# In[115]:


L = [2, 3, 4]


# In[116]:


L[0]


# In[117]:


L[1]


# In[118]:


len(L)


# In[119]:


L.append(10)
print(L)


# In[120]:


L.append("hello")
print(L)


# In[121]:


L[4] = 11
print(L)


# In[122]:


L[-1]


# In[123]:


L[-2]


# In[124]:


L[-0]


# In[125]:


L


# In[126]:


L[1:4]


# In[127]:


L[1:-1]


# In[128]:


L[2:-1]


# In[129]:


L[1:-2]


# In[130]:


L[1:-1:2]


# In[131]:


L


# In[133]:


L[::-2]


# In[ ]:


Lm = ["Good bye", 3, print_greetings]


# `L[i:j]` means take `i-j` elements, starting at `i` included

# In[ ]:


middle = len(Lb)//2
print(middle)
print(Lb[:middle])
print(Lb[middle:])


# In[ ]:


pseudo_matrix = [[1,2],[3,4]]


# In[ ]:


pseudo_matrix[0][1]


# ## For loops

# In[143]:


for i in range(10):
    if i > 5:
        break
    print(i)


# In[136]:


L


# In[139]:


for x in L:
    print(x**2)


# In[140]:


list(range(10))


# In[142]:


range(10000000000000000000000000000)


# ## Variables

# Pointers (two lists), [Python tutor](http://www.pythontutor.com/visualize.html#mode=edit)? args by reference, copy with `list`, deep copy?, `is`, tuples

# In[144]:


L = [2,3,4]


# In[145]:


L_ = L


# In[146]:


L_[0] = 100


# In[147]:


print(L_)


# In[148]:


print(L)


# In[149]:


print(L)


# In[150]:


print(L_)


# In[151]:


L is L_


# In[152]:


L_copy = L[:]


# In[153]:


print(L_copy)


# In[154]:


L is L_copy


# In[156]:


import copy


# In[ ]:


copy.deepcopy


# In[169]:


L.sort()


# In[170]:


L


# In[171]:


L.reverse()


# In[172]:


L


# In[ ]:





# In[166]:


y  = 10
def add_y(x):
    y = 100
    return x + y


# In[167]:


add_y(100)


# In[168]:


y


# In[165]:


add_y(100)


# In[158]:


L = [2,3,4]


# In[159]:


add_10(L)


# In[160]:


L


# In[174]:


L + L


# In[ ]:





# ## Linear algebra

# `array`, vectors, matrices, shape, access `[3,4]`, difference with lists, no append, `concatenate`

# Difference vector matrices

# In[173]:


V = array([2.,3.,4])


# In[175]:


V + V


# In[176]:


M = array([[2,.3],[1,4]])


# In[177]:


print(M)


# In[178]:


V


# In[179]:


V[0]


# In[180]:


M[0,0]


# In[181]:


V


# In[182]:


V * V


# In[183]:


shape(V)


# In[185]:


CV = array([[2.],[3.],[4.]])


# In[186]:


print(CV)


# In[187]:


shape(CV)


# In[188]:


RV = array([[2.,3,4]])


# In[189]:


print(RV)


# In[190]:


shape(RV)


# In[192]:


row_0 = [3,4,5.]


# In[193]:


M = array([row_0])


# In[194]:


print(M)


# In[195]:


shape(M)


# In[196]:


V


# In[197]:


V.reshape((1,3))


# In[198]:


M = V.reshape((3,1))


# In[199]:


T = arange(8).reshape((2,2,2))


# In[200]:


print(T)


# In[201]:


arange(10)


# In[202]:


array(list(range(10)))


# `concatenate`

# pointwise operations,

#  `dot`, 

# In[204]:


M = arange(4).reshape((2,2))


# In[205]:


print(M)


# In[206]:


V = array([2,3])


# In[207]:


M*V # NOT matrix vector multiplication!!!


# In[208]:


dot(M,V)


# In[209]:


dot(V,M)


# In[210]:


dot(V,V)


# In[211]:


CV = V.reshape((2,1))


# In[212]:


dot(M,CV)


# In[214]:


shape(CV)


# In[215]:


CV.T


# In[216]:


shape(CV.T)


# In[217]:


shape(V)


# In[218]:


V.T


# In[219]:


shape(V.T)


# In[222]:


V * V.reshape((2,1))


# In[213]:


dot(CV,M)


# `shape`, `.shape`. `[:,i]`. `transpose`, `.T`, vector transpose. `shape`, `reshape`, column & row matrices. `reshape(-1)`. 

# (`flags`?)

# Array creation: `zeros`, `ones`, `empty`, `eye` (`identity`)

# In[224]:


zeros((2,3))


# In[226]:


ones((3,2))


# In[227]:


identity(3) # eye(3)


# Solving linear systems. `allclose`

# In[230]:


print(M)
print(V)
x = solve(M,V)
print(x)
print(dot(M,x))
print(V)


# Slicing and shape

# ### Concatenation

# Concatenation with `concatenate`, `array`, block matrices together, vectors into row or columns.

# ## Plotting

# same syntax, no hold, figure, `axis('equal')`. `title`, `xlabel`, `ylabel`, `label`, `legend`.

# In[234]:


xs = linspace(0,2*pi,100)
ys = sin(xs)
zs = cos(3*xs)
plot(xs, ys, 'o')
plot(xs, zs, '.')
figure()
plot(xs, ys+.3*zs)
savefig('name.pdf')


# In[ ]:


plot(xs,ys)
figure()
plot(xs,zs)


# In[ ]:


get_ipython().run_line_magic('pinfo', 'plot')


# 0702683132