Linux: mount folder to different folders

Code:

mount -o bind /media/disk1/pictures /home/user1/pictures
mount -o bind /media/disk1/pictures /home/user2/pictures

for add a fstab entry to auto-mount at startup.

Code:

/media/disk1/pictures /home/add1cker/pictures none defaults,bind 0 0

OpenGL Tutorial

 Common libs for start

$sudo apt-get install freeglut3-dev

Matrix Class [3]

Error:
_dl_check_map_versions: Assertion `needed != ((void *)0)' failed!

Fixed using -lpthread parameter [2].


References:


[1] https://www.opengl.org/wiki/Programming_OpenGL_in_Linux:_GLX_and_Xlib

[2]  http://stackoverflow.com/questions/20007961/error-running-a-compiled-c-file-uses-opengl-error-inconsistency-detected
[3] http://www.songho.ca/opengl/index.html
     http://www.songho.ca/opengl/gl_matrix.html#example1
[4] Image Libraries
      https://www.opengl.org/wiki/Image_Libraries
[5] SFML
      http://www.sfml-dev.org/tutorials/2.3/start-linux.php

git commands

References:
[1] https://git-scm.com/book/en/v2/Git-Branching-Basic-Branching-and-Merging

Raspberry pi 3

1) user and passwords:

Distribution   | Username   | Password
---------------|------------|-------------
Debian Squeeze | pi         | raspberry
Arch           | root       | root
QtonPi         | root       | rootme
Raspbian       | pi         | raspberry
OpenElec       | root       | openelec
Pidora         | root       | raspberrypi
RISC OS        | n/a        | n/a
raspbmc        | pi         | raspberry

2) add users

$sudo adduser username

$usermod -aG sudo username

3) Ports

$lsof -nP -i | grep LISTEN
$netstat -tlpn | grep LISTEN
 

4) vncserver (reinstall, by default sometime doesn't works)

$sudo apt-get install tightvncserver 

5) Firewalls

iptables -I INPUT -p tcp --dport 5900 -j ACCEPT
iptables -I INPUT -p tcp --dport 5901 -j ACCEPT

Resources:

[1] https://www.digitalocean.com/community/tutorials/how-to-create-a-sudo-user-on-ubuntu-quickstart

[2] direct way https://www.shellhacks.com/how-to-grant-root-access-user-root-privileges-linux/

[3] vncserver https://quaintproject.wordpress.com/2013/03/24/establish-a-vnc-connection-to-your-raspberry-pi-from-a-linux-pc/

smoothing

References:

[1] smoothing python https://matthew-brett.github.io/teaching/smoothing_intro.html

Optimize code C/C++

If you are using linux: use getchar_unlocked() and putchar_unlocked() for taking fast single character I/O.
In Windows the equivalent is getchar() and puchar() repectively


Resources:
[1] fast input/output https://ideone.com/BrsDz4


Enteprise solutions:
[1] http://www.fastformat.org/

Computational Resources

Resources:
[1] Computational Biophysics Software http://www.ks.uiuc.edu/Research/vmd/vmd-1.9.1/

Programming online C++ and others

Online programming tools

Resources:
[1] C++, Python  https://repl.it/@melhorum


[2] Multi Language Support https://code.dcoder.tech/

[3] Account for C/C++, C#, Java  http://rextester.com
[4] http://www.onlinegdb.com/

Store on EEUU for Buy

Stores:
[1] https://www.shipito.com/pt/shipito-pricing

Python 2.7 pip

Resolving error on python 2.7 using pip: ImportError: No module named _internal

$wget https://pypi.python.org/packages/e7/a8/7556133689add8d1a54c0b14aeff0acb03c64707ce100ecd53934da1aa13/pip-8.1.2.tar.gz
$tar -xzvf pip-8.1.2.tar.gz
$cd pip-8.1.2
$sudo python setup.py install

Lectures

https://arxiv.org/pdf/1803.04189.pdf

OpenCV 2.4.9 and 3.4.1 Compiling

2.4.x

CUDA_nppi_LIBRARY  CUDA 7.5 -> 8.0 (was removed)
  -D WITH_CUDA=OFF ..

c++ 6 fatal error: stdlib.h: No such file or directory

 export CC=path_of_gcc/gcc-version
 export CXX=path_of_g++/g++-version
 cmake  path_of_project_contain_CMakeList.txt
 make 

OR

 #Current version is 6, but we need to compile using another version (installed for sure)

$CC="gcc-4.9" CXX="g++-4.9" cmake /CMakeLists.txt 

OR$cmake -G "Unix Makefiles" -DCMAKE_CXX_COMPILER=/usr/bin/g++ CMAKE_C_COMPILER=/usr/bin/gcc -DCMAKE_BUILD_TYPE=RELEASE -DCMAKE_INSTALL_PREFIX=/usr/local -DWITH_TBB=ON -DBUILD_NEW_PYTHON_SUPPORT=ON -DWITH_V4L=ON -DINSTALL_C_EXAMPLES=ON -DINSTALL_PYTHON_EXAMPLES=ON -DBUILD_EXAMPLES=ON -DWITH_QT=ON -DWITH_OPENGL=ON -DBUILD_FAT_JAVA_LIB=ON -DINSTALL_TO_MANGLED_PATHS=ON -DINSTALL_CREATE_DISTRIB=ON -DINSTALL_TESTS=ON -DENABLE_FAST_MATH=ON -DWITH_IMAGEIO=ON -DBUILD_SHARED_LIBS=OFF -DWITH_GSTREAMER=ON -DWITH_OPENMP=OFF -DWITH_CUDA=OFF -DBUILD_opencv_gpu=OFF ..

3.4.x

Unknown CMake command "ocv_append_source_files_cxx_compiler_options".

This happened when the opencv_contrib version is no compatible with your current version.

cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D WITH_TBB=ON -D BUILD_NEW_PYTHON_SUPPORT=ON -D WITH_V4L=ON -D INSTALL_C_EXAMPLES=ON -D INSTALL_PYTHON_EXAMPLES=ON -D BUILD_EXAMPLES=ON -D WITH_QT=ON -D WITH_OPENGL=ON -D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules/ ..


$make
$sudo make install
$sudo ldconfig

After installation, if doesn't compile, check the files opencv.conf and opencv.pc:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#/etc/ld.so.conf.d/opencv.conf
/usr/local/lib
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#/usr/local/lib/pkgconfig/opencv.pc

prefix=/usr/local
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir_old=${prefix}/include/opencv
includedir_new=${prefix}/include

Name: OpenCV
Description: Open Source Computer Vision Library
Version: 2.4.13.6
Libs: -L${exec_prefix}/lib -lopencv_contrib -lopencv_legacy -lopencv_stitching -lopencv_nonfree -lopencv_superres -lopencv_ocl -lopencv_objdetect -lopencv_ml -lopencv_ts -lopencv_videostab -lopencv_video -lopencv_photo -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_imgproc -lopencv_flann -lopencv_core -L/usr/lib/x86_64-linux-gnu -lIlmThread -lHalf -lIex -lIlmImf -lImath -ljasper -ltiff -lpng -ljpeg -lavutil -lswscale -lswresample -lavcodec -lz -llzma -lxcb-shape -lxcb-render -lxcb-xfixes -lxcb-shm -lxcb -lavformat -lv4l2 -lv4l1 -ldc1394 -lGL -lGLU -latomic -ltbb -lrt -lpthread -lm -ldl -lstdc++
Cflags: -I${includedir_old} -I${includedir_new}

 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


Resources:

[1] opencv github (choice right branch) https://github.com/opencv/opencv

[1] opencv_contrib is just from 3.0 .. https://github.com/opencv/opencv_contrib/releases
[2] Steps for install () http://karytech.blogspot.com/2012/05/opencv-24-on-ubuntu-1204.html
[3] Script for install under ubuntu16 https://gist.github.com/fortunto2/20a9696c7fc23ef18f8cfc50e371fe5f
[4] Some variables http://daveaubin.com/index.php/how-to-build-and-install-opencv-2-4-9-on-raspberry-pi/

Signal Processing - Sound Processing

 Resources:
[1] Course and Tutorial https://github.com/AllenDowney/ThinkDSP

Fluid Simulation: Lectures and Resources

CAELinux LiveDVD in your computer to turn it into a free and open engineering development workstation with CAD, CAM, CAE / FEA / CFD, electronic design and 3D printing  features: no licence and even no installation is required ! [2]


Resources:
[1] Laboratory http://lgg.epfl.ch/research_physicsbased_animation.php
[2] CFD Linux distro https://caelinux.com/CMS3/

Courses:
[1] Khan https://pt.khanacademy.org/partner-content/pixar/effects/particle/p/water-simulation

Compiling tris2indicator on Linux Ubuntu 16

change code from MapViewOfFile (Windows) to mmap (Linux) on read_obj.cpp and write_grid.cpp.

$g++ read_obj.cpp vect.cpp global.cpp insert_poly.cpp write_grid.cpp timer.cpp main.cpp -lpthread -lm -o tris2indicator



source code:
[1] http://josiahmanson.com/research/wavelet_rasterization/

Mapping files into memory

• CreateFile(); or OpenFile();
• CreateFileMapping();
• MapViewOfFile();
  

mmap() combines the functions of CreateFileMapping() and MapViewOfFile()

References
[1] https://stackoverflow.com/questions/8391094/equivalent-win-api-in-nix
[2] http://pubs.opengroup.org/onlinepubs/9699919799/functions/mmap.html
[3] mmap example https://gist.github.com/marcetcheverry/991042

AI Courses and Resources

Resources:

 [1] Berkeley course http://ai.berkeley.edu
 [2] Minimax algorithm https://www.geeksforgeeks.org/minimax-algorithm-in-game-theory-set-3-tic-tac-toe-ai-finding-optimal-move/
 [3] Alfa Beta Prunning https://www.geeksforgeeks.org/minimax-algorithm-in-game-theory-set-4-alpha-beta-pruning/

 [4] Full Course, Search slides https://courses.cs.washington.edu/courses/cse473/14au/slides/

Qt Project to MakeFile

qmake -spec macx-g++ x.pro on Mac OS X to generate Makefile
qmake x.pro on linux to generate Makefile (default behaviour)
qmake -spec win32-g++ x.pro on Windows to generate Makefile

References:
[1] https://stackoverflow.com/questions/8571687/how-to-get-a-makefile-from-qmake

Fluid SImulaton Source codes

Compile OceanSurface under Ubuntu 16 [2]
* Install dependences
libglm-dev
libglfw3-dev
libsoil-dev

$g++ -o OceanSurface main.cpp wave.cpp Record.cpp -lGL -lglfw -lGLEW -lfftw3 -lfftw3f -lSOIL


Resources:
[1] splishsplash http://melhorum.blogspot.com.br/2018/05/compile-splishsplash.html
[2] https://github.com/JiashuoLi/OceanSurface
[3] https://ttnghia.github.io/

Ubuntu 16 Setting Screen Samsung SyncMaster T240M

$cvt 1600 1000 #get right values for this resolution
$gtf 1600 1000 60 #alternative


# 1600x1000 59.87 Hz (CVT 1.60MA) hsync: 62.15 kHz; pclk: 132.25 MHz
Modeline "1600x1000_60.00" 132.25 1600 1696 1864 2128 1000 1003 1009 1038 -hsync +vsync
 
$ sudo xrandr --newmode "1600x1000" 132.25 1600 1696 1864 2128 1000 1003 1009 1038 -hsync +vsync  #define

$ sudo xrandr --addmode DVI-I-1 "1600x1000" #register on system

$ xrandr
Screen 0: minimum 320 x 200, current 1600 x 900, maximum 16384 x 16384
DVI-I-1 connected primary 1600x900+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 59.95 +
1600x1200 60.00
1280x1024 75.02 60.02
1280x960 60.00
1152x864 75.00
1024x768 75.08 70.07 60.00
832x624 74.55
800x600 72.19 75.00 60.32 56.25
640x480 75.00 72.81 66.67 60.00
720x400 70.08
1600x900 59.95*
1600x1000 59.87
DVI-I-2 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)
1600x900_60.00 (0x58e) 118.250MHz -HSync +VSync
h: width 1600 start 1696 end 1856 total 2112 skew 0 clock 55.99KHz
v: height 900 start 903 end 908 total 934 clock 59.95Hz

* Set permanent settings using ~/.xprofile (for example)
$vi ~/.xprofile
#
xrandr --newmode "1600x1000" 132.25 1600 1696 1864 2128 1000 1003 1009 1038 -hsync +vsync 
xrandr --addmode DVI-I-1 "1600x1000"


* Problem: After nvidia drivers installation this doesn't works (crap)



$xrandr --fb 1600x1000 #show
xrandr: specified screen 1900x1000 not large enough for output DVI-I-3 (1920x1200+0+0)
xrandr: Configure crtc 0 failed
X Error of failed request:  BadValue (integer parameter out of range for operation)
#or
X Error of failed request:  BadMatch (invalid parameter attributes)

$xrandr --output DVI-I-3 --scale 1x0.85  #this solve  after nvidia drivers installation



References:
http://ubuntuhandbook.org/index.php/2017/04/custom-screen-resolution-ubuntu-desktop/