ImageJ downscale image or stack

Downscaling a stack, to exactly N/M (ex: 256/2) in each axis, in float precision,

to get the closest result to the average value of a group of voxels,

select BOTH bilinear interpolation AND average (tick on) !

Switch between nvidia GPUs for display via X settings, if bios doesn't have switching options

You might want to reserve a specific GPU for computing. This might be your "default" display GPU :(

If the Bios options allow you to select a GPU for display, that's your preferred option. If the bios does not offer this option, here is a hack, for screens with multiple I/O ports, or if you have multiple screens at hand:

- with computer off, wire the less preferred cable to the default GPU.

- Boot and shutdown, to make sure this default display layout works and config file xorg.conf is updated.

- boot

- create a backup copy of /etc/X11/xorg.conf

- turn off computer

- plug the preferred cable into the preferred GPU (aka new wiring), while the original wiring for the original display layout is left unchanged


- boot up in graphics mode

- $ sudo nvidia-settings

- Go to X Server Display Configuration

- click icon of disabled monitor (its the one you newly wired). Tip: each connected I/O cable is seen as an original monitor, even wired to 1 physical monitor

- in "Configuration", select "Separate X screen"

- reboot; now the new wiring services a slave X screen

- $ sudo favorite_editor /etc/X11/xorg.conf

- and edit the "Server Layout" to mimic the layout you had before (refer to backup), with new device and screen pointers.

The catch: now all the booting info goes thru the old wiring until xorg.conf is retrieved and its settings enforced. The old wiring may be kept in place, so you switch inputs and peek at the boot info.

KDE (kubuntu 12.04) some settings cannont be enabled

check if some files /home/username/.kde/share/config/ are owned by root instead of username, ex: systemsettingsrc, kxkbrc

KDE desktop panel restart

killall plasma-desktop
plasma-desktop

 (http://ubuntuforums.org/showthread.php?t=1264937)

Touchpad control under KDE linux

1. install kde-config-touchpad package.
2. Run Utilities->Touchpad Management and the application will have the option in GUI. (http://askubuntu.com/questions/46299/how-to-disable-touchpad-tapping-when-typing-on-keyboard)

 NOTE:
might not run properly from GUI.

In my case: $ sudo synaptiks did the job.

How to Set Emacs's User Interface to Modern Conventions

http://ergoemacs.org/emacs/emacs_make_modern.html

Linux OS freezes

If it locks up completely, you can REISUB it, which is a safer alternative to just cold rebooting the computer. REISUB by: While holding Alt and the SysReq (Print Screen) keys, type REISUB. R: Switch to XLATE mode E: Send Terminate signal to all processes except for init I: Send Kill signal to all processes except for init S: Sync all mounted file-systems U: Remount file-systems as read-only B: Reboot REISUB is BUSIER backwards, as in "The System is busier than it should be", if you need to remember it. Or mnemonically - R eboot; E ven; I f; S ystem; U tterly; B roken. * In the event you're forced to do this, do it slowly. Let a few seconds pass in between each keypress so that the commands you're invoking have a chance to finish before you go to the next one. http://askubuntu.com/questions/4408/what-should-i-do-when-ubuntu-freezes/36717#36717