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@nicoguaro
nicoguaro / least_sq_fit.py
Created May 8, 2013
Compute the least square fitting for a function of two variables and also the coefficient of determination (R**2).
View least_sq_fit.py
from scipy import zeros, dot, linspace, linalg, array, sqrt, loadtxt, meshgrid
from scipy import shape, mean
from numpy.linalg import norm
from scipy.optimize import minimize
x = loadtxt('x.txt')
t = loadtxt('t.txt')
S = loadtxt('Syy.txt')
X, T = meshgrid(x,t)
@nicoguaro
nicoguaro / poly_lsq.py
Last active Dec 18, 2015
Computes the least squares fitting for a polynomial of order k, for a data-set in a file with columns for x and y. The condition k< n should be satisfied.
View poly_lsq.py
"""
Computes the least squares fitting for a polynomial of order k.
The condition k< n should be satisfied.
"""
from scipy import zeros, dot, array, loadtxt
from scipy import shape, mean
from numpy.linalg import norm, solve
@nicoguaro
nicoguaro / ode.py
Created Sep 30, 2013
Solve and first order ODE system, the right hand side is given as a string.
View ode.py
from numpy import *
from scipy import integrate
def ode(f, t0, tf, n_steps, X0):
"""
Solve an ODE in the time interval [t0, tf] using a number of steps given
by nsteps, with initial conditions X0. The differential equation is
written as a system of linear equations
x'_i = f(x_j)
@nicoguaro
nicoguaro / plotdf.py
Last active Nov 24, 2020
Plot the vector field for an autonomous ODE written in the form x' = F(x,y), y' = G(x,y).
View plotdf.py
import numpy as np
from matplotlib import pyplot as plt
def plotdf(f, xran=[-5, 5], yran=[-5, 5], grid=[21, 21], color='k'):
"""
Plot the direction field for an ODE written in the form
x' = F(x,y)
y' = G(x,y)
The functions F,G are defined in the list of strings f.
@nicoguaro
nicoguaro / videos.sh
Last active Nov 6, 2019
Generate videos from a sequence of images with consecutive numbering
View videos.sh
#!/bin/bash
#
# Generate an animation (.avi, .gif) from a sequence of image with
# the same name and a sequence of numbers.
#
mencoder "mf://*.png" -mf type=png:fps=5 -ovc lavc -o vid.avi
convert img*.png -delay 20 -loop 0 -channel Alpha vid.gif
rm img*.png
View superquads.ipynb
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@nicoguaro
nicoguaro / zoomed_inset_axes_example.py
Created Oct 7, 2014
An example of a zoom in a simple plot using `zoomed_inset_axes`.
View zoomed_inset_axes_example.py
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1.inset_locator import zoomed_inset_axes
from mpl_toolkits.axes_grid1.inset_locator import mark_inset
import numpy as np
fig, ax = plt.subplots()
View circular_membrane.py
from __future__ import division
from numpy import pi, sin, cos, mgrid
from scipy.special import jn, jn_zeros
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
import matplotlib.animation as animation
from matplotlib import rcParams
# In Windows the next line should provide the full path to convert.exe
@nicoguaro
nicoguaro / plot_guy.py
Last active Aug 29, 2015
Plot stick men.
View plot_guy.py
import matplotlib.pyplot as plt
import numpy as np
def plot_guy(x, y, frown=False, **plot_args):
"""Plot a stick man of 2 units wide and 6 units tall.
http://nbviewer.ipython.org/gist/theandygross/4544012
"""
an = np.array(np.linspace(0,2*np.pi,100))
head, = plt.plot(np.cos(an)+x, np.sin(an)+y + 5, **plot_args)
View butterfly_curves.py
"""
Plot multiple butterfly curves.
"""
import numpy as np
import matplotlib.pyplot as plt
def curve(turns, npts):
t = np.linspace(0, 2*turns*np.pi, npts)
x = np.sin(t)*(np.exp(np.cos(t))- 2*np.cos(4*t) - np.sin(t/12)**5)