x lines of Python¶

Code golf: Let x = 1¶

Code golf... reducing functions to their smallest possible size. Like x lines of Python, but x = 1.

This notebook goes with a blog post of the same name.

Ricker wavelet: 95 chars¶

First, define our short function:

In [1]:

def r(l,d,f):import numpy as n;t=n.arange(-l/2,l/2,d);k=(n.pi*f*t)**2;return t,(1-2*k)/n.exp(k)

Now import the version in bruges for comparison:

In [2]:

from bruges.filters import ricker

Plot the two together:

In [3]:

import matplotlib.pyplot as plt
%matplotlib inline

t, w = r(0.128, 0.004, 25)

plt.figure(figsize=(10,3))
plt.plot(t, ricker(0.128, 0.004, 25), 'o')  # Compare to bruges.
plt.plot(t, w)
plt.xlim(-0.07, 0.07)
plt.show()

We can use the inspect module ot compare the source code:

In [10]:

import inspect
inspect.getsource(r).strip()

Out[10]:

'def r(l,d,f):import numpy as n;t=n.arange(-l/2,l/2,d);k=(n.pi*f*t)**2;return t,(1-2*k)/n.exp(k)'

In [11]:

len(inspect.getsource(r).strip())

Out[11]:

In [12]:

len(inspect.getsource(ricker).strip())

Out[12]:

Ormsby wavelet: 169 chars¶

In [13]:

def o(l,d,f):import numpy as n;t=n.arange(-l/2,l/2,d);p=n.pi;f,g,h,i=f;λ=lambda ϕ,t:(n.sinc(ϕ*t)*p*ϕ)**2;A=(λ(i,t)-λ(h,t))/(i-h)-(λ(g,t)-λ(f,t))/(g-f);return t,A/max(A)

In [14]:

from bruges.filters import ormsby

In [15]:

import matplotlib.pyplot as plt
%matplotlib inline

t, w = o(0.128, 0.004, [8, 12, 60, 80])

plt.figure(figsize=(10,3))
plt.plot(t, ormsby(0.128, 0.004, [8, 12, 60, 80]), 'o')  # Compare to bruges.
plt.plot(t, w)
plt.xlim(-0.07, 0.07)
plt.show()

In [16]:

inspect.getsource(r).strip()

Out[16]:

'def r(l,d,f):import numpy as n;t=n.arange(-l/2,l/2,d);k=(n.pi*f*t)**2;return t,(1-2*k)/n.exp(k)'

In [17]:

len(inspect.getsource(o).strip())

Out[17]:

In [18]:

len(inspect.getsource(ormsby).strip())

Out[18]:

Aki-Richards: 192 chars¶

In [19]:

def r(a,c,e,b,d,f,t):import numpy as n;w=f-e;x=f+e;y=d+c;p=n.pi*t/180;s=n.sin(p);return((w/x)-(y/a)**2*w/x*s**2+((b-a)/(b+a))/n.cos((p+n.arcsin(b/a*s))/2)**2-4*((y/2)/a)**2*((d-c)/(y/2))*s**2)

In [20]:

from bruges.reflection import akirichards

In [23]:

# 4-term Aki-Richards equation in 255 characters!
# http://subsurfwiki.org/wiki/Aki–Richards_equation
import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline

rock1 = (2300, 1200, 2500)  # Vp, Vs, rho for layer 1
rock2 = (2400, 1250, 2450)  # Vp, Vs, rho for layer 2
theta1 = np.arange(40)

result = r(*rock1, *rock2, np.arange(40))

plt.figure(figsize=(10,4))
plt.plot(akirichards(*rock1, *rock2, np.arange(40)), 'o')
plt.plot(result)

plt.show()

In [26]:

inspect.getsource(r).strip()

Out[26]:

'def r(a,c,e,b,d,f,t):import numpy as n;w=f-e;x=f+e;y=d+c;p=n.pi*t/180;s=n.sin(p);return((w/x)-(y/a)**2*w/x*s**2+((b-a)/(b+a))/n.cos((p+n.arcsin(b/a*s))/2)**2-4*((y/2)/a)**2*((d-c)/(y/2))*s**2)'

In [27]:

len(inspect.getsource(r).strip())

Out[27]:

In [28]:

len(inspect.getsource(akirichards).strip())

Out[28]:

Exact Zoeppritz: 386 chars¶

From Dvorkin et al. (2014). Seismic Reflections of Rock Properties. Cambridge.

I can't find a way to get rid of any of the newlines or indents.

In [29]:

def z(α,β,ρ,χ,ψ,ω,t):import numpy as n;t=n.pi*t/180;C=n.cos;A=n.arcsin;S=n.sin;p=S(t)/α;u=A(p*χ);ϕ=A(p*β);υ=A(p*ψ);v=lambda w,x,y,z: y-2*y*S(z)**2+2*w*S(x)**2;a=ω-2*ω*S(υ)**2-ρ+2*ρ*S(ϕ)**2;b=v(ρ,ϕ,ω,υ);x=v(ω,υ,ρ,ϕ);d=2*(ω*ψ**2-ρ*β**2);E=b*C(t)/α+x*C(u)/χ;F=b*C(ϕ)/β+x*C(υ)/ψ;G=a-d*C(t)/α*C(υ)/ψ;H=a-d*C(u)/χ*C(ϕ)/β;return(F*(b*C(t)/α-x*C(u)/χ)-H*p**2*(a+d*C(t)/α*C(υ)/ψ))/(E*F+G*H*p**2)

In [30]:

from bruges.reflection import zoeppritz_rpp

In [31]:

result = z(*rock1, *rock2, np.arange(40))

plt.figure(figsize=(10,4))
plt.plot(zoeppritz_rpp(*rock1, *rock2, np.arange(40)), 'o')
plt.plot(result)
plt.show()

In [32]:

inspect.getsource(z).strip()

Out[32]:

'def z(α,β,ρ,χ,ψ,ω,t):import numpy as n;t=n.pi*t/180;C=n.cos;A=n.arcsin;S=n.sin;p=S(t)/α;u=A(p*χ);ϕ=A(p*β);υ=A(p*ψ);v=lambda w,x,y,z: y-2*y*S(z)**2+2*w*S(x)**2;a=ω-2*ω*S(υ)**2-ρ+2*ρ*S(ϕ)**2;b=v(ρ,ϕ,ω,υ);x=v(ω,υ,ρ,ϕ);d=2*(ω*ψ**2-ρ*β**2);E=b*C(t)/α+x*C(u)/χ;F=b*C(ϕ)/β+x*C(υ)/ψ;G=a-d*C(t)/α*C(υ)/ψ;H=a-d*C(u)/χ*C(ϕ)/β;return(F*(b*C(t)/α-x*C(u)/χ)-H*p**2*(a+d*C(t)/α*C(υ)/ψ))/(E*F+G*H*p**2)'

In [33]:

len(inspect.getsource(z).strip())

Out[33]:

In [34]:

len(inspect.getsource(zoeppritz_rpp).strip())

Out[34]: