[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

cputime() returns incorrect values

From: Anton Dereventsov
Subject: cputime() returns incorrect values
Date: Sat, 1 Sep 2018 21:03:43 -0500 (CDT)

The following simple script generates and multiplies two random 1000-by-1000
matrices for 20 iterations and measures how long (in terms of both the
wall-clock time and the cpu time) each iteration was executing.

Here is the code:

And here is the output that I get:

The wall-clock time measured by tic-toc is believable but the cpu time is
clearly false: sometimes it is negative and sometimes it is exactly 0 or 1.
These particular results were obtained in Octave 4.2.2 on Windows 7 machine
with Intel i7-3610QM cpu but I observed the similar output on Ubuntu 16.04
with Intel Xeon E3-1535M v6.
Coincidentally, in Matlab the same code on the same machines returns
reasonable cpu time.
Is this a bug or am I doing something terribly wrong?


Sent from:

reply via email to

[Prev in Thread] Current Thread [Next in Thread]