savetxt & close file + python + numpy

Question

I was wondering if anyone could help me with one problem that I have when using the python + numpy function 'savetxt'.

The problem is:

(1) I have a subroutine in which I save a matrix (numerical data) into a textfile (using the function savetxt):

For example:

import numpy as np
A = np.matrix('1 2; 3 4')
np.savetxt('myfile.txt', A, fmt='%-7.8f', delimiter=',')

(2) Then, I have to use that data in another program. It is a time-domain simulation and I need to read the data at each iteration. I observe the following:

• Reading the data from the file that I have created makes the process much more slower.

• The curious thing is that, if I use the same data (without saving it before with my subroutine), the program goes fast. For example, if I save the data, it goes slow, but if I restart the computer, it goes fast.

Perhaps the file is not closed when I use it later.

I would be very grateful if someone can give me some clues about possible causes of this problem.

Thank you very much.

Javier

Answer 1

I doubt that the savetxt method does not close the file at the end. Anyway, to be sure, you can save your file this way:

with open('myfile.txt', 'wb') as f:
    np.savetxt(f, A, fmt='%-7.8f', delimiter=',')

In which case you are sure that the file is closed afterwards.