Sorry about asking a stupid question. I'm just trying to use this, but don't know anything.

My problem is: I want to plot graph with python code.

I run it in terminal (I'm using mac) by calling: pdflatex -shell-escape plot_air_drag.tex

! I can't find file `plot_air_drag.tex'.

<*> plot_air_drag.tex

(Press Enter to retry, or Control-D to exit)

Please type another input file name:

What is the way to run it?

Here is my code:




    from pylab import *
from scipy.integrate import odeint
from functools import partial

## set initial conditions and parameters
g = 9.81            # acceleration due to gravity
th = 45.            # set launch angle
th = th * np.pi/180.   # convert launch angle to radians
v0 = 20.0           # set speed

x0=0                # specify initial conditions
vx0 = v0*sin(th)
vy0 = v0*cos(th)

## define function to compute f(X,t)
def f_func_k(k,state,time):
    f = zeros(4)    # create array to hold f vector
    f[0] = state[2] # f[0] = x component of velocity
    f[1] = state[3] # f[1] = x component of velocity
    f[2] = - k*(f[0]**2 + f[1]**2)**(0.5)*f[0]         # f[2] = acceleration in x direction
    f[3] = -g - k*(f[0]**2 + f[1]**2)**(0.5)*f[1]       # f[3] = acceleration in y direction
    return f

def gen_plot_data(s,k):
    f_func = partial(f_func_k,k)

    ## set initial state vector and time array
    X0 = [ x0, y0, vx0, vy0]        # set initial state of the system
    t0 = 0.
    # tf = input("Enter final time: ")
    # tau = input("Enter time step: ")
    tf = 3
    tau = 0.05

    # create time array starting at t0, ending at tf with a spacing tau
    t = arange(t0,tf,tau)

    ## solve ODE using odeint
    X = odeint(f_func,X0,t) # returns an 2-dimensional array with the
    # first index specifying the time and the
    # second index specifying the component of
    # the state vector

    # putting ':' as an index specifies all of the elements for
    # that index so x, y, vx, and vy are arrays at times specified
    # in the time array
    x = X[:,0]
    y = X[:,1]
    vx = X[:,2]
    vy = X[:,3]

    xy = zip(x,y)


    \begin{axis}[no marks,samples=100,axis lines=center,xlabel=$x$,ylabel=$y$,enlargelimits]
        \addplot table {plotdata1.dat};%
        \addplot[magenta] table {plotdata2.dat};%

  • 4
    Are you in the correct directory? You need to change to the path where the .tex file is located. Mar 19 '14 at 12:51
  • Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. Mar 20 '14 at 9:42

Works fine on Mac with 10.9.2 and with pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013). But:

Save your file as plot_air_drag.tex (the error message indicates you are using an different file name)

Modify your preamble


Start Terminal,

Type cd Space and drop the folder with the files there.

Hit Enter.

And use pdflatex -shell-escape plot_air_drag.tex enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.