Applications


IEEETran Latex Template – Add Copyrights on left bottom of first page of Conference class

Using the conference class in the IEEETran Latex template, it blocks you from using the IEEEpubid command that can be used to add the copyright note on the bottom of the screen.

Attempt 1 – Enable overrides only

We added the IEEEoverridecommandlockouts command right after the documentclass directive, that allows us to use functionality in IEEETran that should be blocked depending on the document class.
Then we used the IEEEpubid command right after the documentclass directive to create and print the copyright note:

\IEEEpubid{978-1-5386-2880-5/17/\$31.00~\copyright~2017 IEEE}

Doing so, resulted in printing the copyright note in the bottom middle of the first page. The conference class is a two column style, the left column got pushed up a bit to make space, while the right did not. In the end, half of the copyright note was overlapping with the second column.

Attempt 2 – Solution – Customize IEEEpubid as well

After documentclass we added the IEEEoverridecommandlockouts command to enable functionality that is blocked for the conference class.
Then we created our own IEEEpudid command that places itself in a column and not a page as follows:

\documentclass[conference]{IEEEtran}
%Enabled blocked functionality
\IEEEoverridecommandlockouts
%Define custom IEEEpubid that will place it self in a column and not a page, suitable from conference class
\IEEEpubid{\makebox[\columnwidth]{978-1-5386-2880-5/17/\$31.00~\copyright~2017 IEEE \hfill} \hspace{\columnsep}\makebox[\columnwidth]{ }}

Finally after the maketitle command we added IEEEpubidadjcol to give more space between the copyright note and the body of first column.

\maketitle
%Add space between copyright and text
\IEEEpubidadjcol

Making an animated torus in gnuplot and gimp

The gnuplot code in this article, creates several frames of a 3D torus with a visible structural grid from different viewing angles, like the one in the image below.

torus.gnuplot (compressed) (93 downloads)

In geometry, a torus (plural tori) is a surface of revolution generated by revolving a circle in three-dimensional space about an axis coplanar with the circle. If the axis of revolution does not touch the circle, the surface has a ring shape and is called a torus of revolution.

From Wikipedia https://en.wikipedia.org/wiki/Torus

By modifying the circles and rings variables in the script you can increase and decrease the number of circles and rings that appear on your torus.
The above image was generated using 60 circles and 30 rings.

To better explain what a circle and what a ring is, please have a look at the following two examples.

The following torus has 10 circles and 30 rings.

The next one has 60 circles and 10 rings.

The last torus has 10 circles and 10 rings.

Using the script, you can also play around with the set view command and the for loop to change the number of frames that will be produced and what movement should the camera perform before printing.

torus.gnuplot (compressed) (93 downloads)

set terminal pngcairo transparent enhanced font "arial,10" fontscale 1.0 size 700, 400

unset key
unset border
unset tics

set dummy u, v

circles=60
rings=30

set parametric
set isosamples circles, rings
set hidden3d back offset 1 trianglepattern 3 undefined 1 altdiagonal bentover
set urange [ -pi : pi ] noreverse nowriteback
set vrange [ -pi : pi ] noreverse nowriteback

do for [i=1:360/circles] {
 set view 25, i, 1, 1
 set output sprintf('game-of-life-torus.%03.0f.png', i)
 splot cos(u)+.5*cos(u)*cos(v),sin(u)+.5*sin(u)*cos(v),.5*sin(v) with lines
}

torus.gnuplot (compressed) (93 downloads)

Below, you can see two examples of animation we build together using the gimp application.

Showing one frame at a time.

Accumulating all frames into one, until the loop is reset.

To create the animation we followed the next steps:

  1. Executed gnuplot torus.gnuplot to generated the frames.
  2. Then we started the gimp and from the menu File we chose the option Open as layers... (Ctrl + Alt + o).
  3. We selected all the images we wanted for our animation and pressed the Open button.
  4. The Layers - Brushes window got populated by the new frames. Please note that window you can use that to change the order of the frames (which are now the layers).
  5. Following, from the menu File we chose the option Export As... (Shift + Ctrl + E), from the pop-up window we selected the type of the file to be gif and pressed the Export button.
  6. At the final pop-up window, we enabled the As animation checkbox, then at the Frame disposal where unspecified dropdown menu we chose One frame per layer (replace) and hit the Export button which produce the first animation in this article (two images up).

This figure shows the ‘Layers – Brushes’ window that got populated by the new frames.

From the menu File we chose the option Export As… (Shift + Ctrl + E), from the pop-up window we selected the type of the file to be ‘gif’ and pressed the Export button.

At the final pop-up window, we enabled the As animation checkbox, then at the Frame disposal where unspecified dropdown menu we chose One frame per layer (replace) and hit the Export button which produce the first animation in this article (two images up).

 


Excel / Calc: Convert a Hexadecimal number to Decimal

The following examples allow you to convert hexadecimal values of the format 0xYYYYYY to decimal using a spreadsheet editor like Calc or Excel.

The following codes will remove the first two characters (the value 0x) of the cell B2 and then convert the result to decimal using the HEX2DEC function.

Using the RIGHT function

In this example, we used the RIGHT function with the num_chars parameter to be equal to the number of characters in the cell minus 2. This used to delete the 0x value from the HEX column by removing the first two characters of the cell.
To get the number of characters in the cell we use the LEN function on the cell of interest.

=HEX2DEC(RIGHT(B2,LEN(B2)-2))

Using the SUBSTITUTE function

In the following example we used the SUBSTITUTE function to automatically find the 0x prefix of the HEX value and delete it by replacing it with an empty string.

=HEX2DEC(SUBSTITUTE(B2,"0x",""))

Using the REPLACE function

The last example uses the REPLACE function. Starting from the character in position 1 in the cell, it replaces the sub-string of size 2 with the empty string and thus deleting the prefix. Please note that this function is not zero-based so the first character is at position 1 and not at position 0.

=HEX2DEC(REPLACE(B2,1,2,""))

Functions Legend:

  • RIGHT(text,[num_chars])RIGHT returns the last character or characters in a text string, based on the number of characters you specify in the variable num_chars. RIGHT always counts each character, whether single-byte or double-byte, as 1, no matter what the default language setting is.
  • LEN(text)LEN returns the number of characters in a text string. Again, LEN always counts each character, whether single-byte or double-byte, as 1, no matter what the default language setting is.
  • HEX2DEC(number)HEX2DEC converts a hexadecimal number to decimal.
  • SUBSTITUTE(text, old_text, new_text, [instance_num]) – Substitutes new_text for old_text in a text string. You can use SUBSTITUTE when you want to replace specific text in a text string.
  • REPLACE(old_text, start_num, num_chars, new_text)REPLACE replaces part of a text string, based on the number of characters you specify, with a different text string. Use REPLACE when you want to replace any text that occurs in a specific location in a text string. REPLACE always counts each character, whether single-byte or double-byte, as 1, no matter what the default language setting is.

VirtualBox on Windows: Stuck in capture mode as the keyboard does not have a right Ctrl button

Recently, we got a laptop that did not have a right Ctrl button and we found out after we started a VM with no Guest Additions installed.
Because of these two factors we could not escape the VM capture mode and return to the host OS.

To resolve the issue, we pressed Alt+Ctrl+Del to force the window to escape by entering that specialised Windows security screen and the hit Cancel.
Then, we went to the VirtualBox window and did the following procedure to change the button that allows you to escape the capture mode.

From the VirtualBox Window menu we went to: File –> Preferences –> Input and then clicked on the box next to HOST KEY COMBINATION and then typed the key we wanted to use.


How does ‘git pull’ and ‘git fetch’ differ?

In simple terms, the difference between the two Git commands is that git pull is composed by a git fetch followed by a git merge.

When you use git pull, Git will automatically merge any pulled commits into the branch you are currently working in, without letting you review them first. You will get a prompt only if there is conflict found during automatic merging.

When you use git fetch, Git retrieves any commits from the target branch that do not exist in your current branch and stores them in your local repository. However, it will not merge them with your current branch. To integrate the new commits into your current branch, you need to use git merge manually.
This command is particularly useful if you need to keep your repository up to date, but are working on something that might break if you merge your files.
For example, if you will go offline and you need to have those commits available to you but cannot merge at the time, using git fetch you will download the new commits to your machine without affecting your current code. Later you will be able to merge the new commits to your branch as/when you please.


Select range of lines in Notepad++ using line numbers

In response to a question in this post we proposed the following method to select a range of lines in Notepad++ using the line numbers:

  1. Press Ctrl + G, type the start line and hit Enter to go to the start line.
  2. Then go to the menu, click on Edit and then Begin/End select.
  3. Press again Ctrl + G, and type the end line number and hit Enter to go to it.
  4. Back to the menu, click on Edit and then Begin/End select once more.
    By now you will have your range of lines selected.

Just some notes for setting up a new OS to develop projects on GNU/Linux Fedora

If the project is in C++ and uses mysql then install

sudo dnf install mysql++-devel;

If the project is in C/C++ and you are missing talloc.h install

sudo dnf install libtalloc-devel;

Set your name and email for all git projects

git config --global --edit
Then fill-in the configuration file similar to below
# This is Git's per-user configuration file.
[user]
# Please adapt and uncomment the following lines:
#       name = Michael, George
#       email = [email protected]
[user]
        name = Michael, George
        email = [email protected]
[gui]
        editor = gedit

or use these individual commands to set the configuration

[[email protected] ~]$ git config --global user.name "Michael, George"
[[email protected] ~]$ git config --global user.email "[email protected]"

Increase amount of inotify watchers

If you are using CLion or IntelliJ IDEA by jetbrains increase the amount of inotify watchers.
CLion, IntelliJ (and other tools of jetbrains) use inotify on GNU/Linux to monitor directories for changes. It’s common to encounter the system limit on the number of files they monitor.

inotify requires a watch handle to be set for each directory in the project. Unfortunately, the default limit of watch handles will not be enough for sized projects, and reaching the limit will force the jetbrains platform to fall back to recursive scans of directory trees.

Create a file (as root) called /etc/sysctl.d/idea.conf and add the following content to it to increase the number of watchers to 512K

fs.inotify.max_user_watches = 524288

Then call sysctl to reload the settings and apply the new configuration

[[email protected] ~]$ sudo sysctl -p --system;
  •  -p[FILE] or --load[=FILE]: Load in sysctl settings from the file  specified  or /etc/sysctl.conf if none  given.
    Specifying - as filename means reading data from standard input. Using this option will mean arguments to sysctl are files, which are read in the order they are specified.
    The file argument may be specified as regular expression.
  •  --system: Load settings from all system configuration files.
     /run/sysctl.d/*.conf
     /etc/sysctl.d/*.conf
     /usr/local/lib/sysctl.d/*.conf
     /usr/lib/sysctl.d/*.conf
     /lib/sysctl.d/*.conf
     /etc/sysctl.conf

git: How to move locally committed (but not pushed) changes to a new branch

Recently, we’ve been working on a certain branch, we did some changes and performed a couple of commits that were not pushed on the remote system.

There was a complication and it was decided that the local changes should not be pushed to the branch that we were working on.
Rather, they changes should go to a new branch which eventually will be merged.

As mentioned above, we already had done some changes and we already had performed the commits.

git status would give us the following:

$ git status;
On branch scanner_pdu_parser_master
Your branch is ahead of 'origin/scanner_pdu_parser_master' by 2 commits.
  (use "git push" to publish your local commits)

So, we needed to change the branch for those local commits.

Solution – Move the local commits to a new branch

First we got the name of the current branch using the command:

git branch;

Then, we switched to a new local branch

git checkout -b banana_peeler;

And, we pushed the local branch to the remote system:

git push --set-upstream origin banana_peeler;

Afterwards, we switched back to the previous branch

git checkout apple_peeler;

And reset it back to its original form, removing our local commits from it:

git reset --hard origin/apple_peeler;

Please note that the last command will delete all changes that are not committed as well.
In other words, any file you modified and did not commit or push, they will be reverted back to the original code as well.