Author Archives: news

Add visual studio command prompt to windows explorer context menu

Recently relised visual studio build tool (with cmake support), enables building windows c++ project without GUI. It is essential to accelerate the testing of cross-platform program. It is convenient and decent to add Bash (WSL) and visual studio command line … Continue reading

Posted in Uncategorized | Leave a comment

using cloud space as a private git repo

[answer from stackoverflow] It is absolutely possible – what you probably want to do is create a “bare” git repository in folder Y (git init –bare) and then add that file location as a remote:

======= push and pull … Continue reading

Posted in Uncategorized | Comments Off on using cloud space as a private git repo

BoundaryLayer setup for Gmsh 3D meshing

Precise control of the thickness of the first cell normal to wall, is crucial for  turbulence models like k-epsilon, k-omega. Before moving to turbulence flow simulation for CFD workbench of FreeCAD 2D meshing with boundary layer, tutorial <http://www.iesensor.com/blog/2017/05/24/gmsh_fenics_meshing/> 3D boundary … Continue reading

Posted in Uncategorized | Comments Off on BoundaryLayer setup for Gmsh 3D meshing

from gmsh geo file to fenics mesh with subdomain and boundary facet exported

 

Posted in Programming, Research | Comments Off on from gmsh geo file to fenics mesh with subdomain and boundary facet exported

FreeCAD compatible Fenics mshr geometry building

Fenics geometry building API is based on CGAL, it can import CAD, but can not export CAD file like step. Here is a solution, not fully tested. This file may be further developed in github.

Posted in Uncategorized | Comments Off on FreeCAD compatible Fenics mshr geometry building

solved Fenics (2016.2) cpp code compiling error on ubuntu 16.04

for any expression in Expression for Fenics 2016.2( installed from PPA ) expr = “”” x[2]> {} ? {}:{}”””.format(disc_zmax, lambda_p, lambda_d) print(expr) K = Expression(expr, element=V.ufl_element()) # error in compiling instant error log: ” — The imported target “vtkRenderingPythonTkWidgets” references … Continue reading

Posted in Programming | Comments Off on solved Fenics (2016.2) cpp code compiling error on ubuntu 16.04

Cmake cheatsheet

#Cmake cheat sheet in markdown

Posted in Uncategorized | Comments Off on Cmake cheatsheet

c and cpp pitfalls, mixing signed and unsigned integer, implicit conversion

1. mixing unsigned and sign int is a bad idea first of all, remember: signed int types will be implicitly converted to unsigned if sizeof(signed int types) == sizeof(unsigned int types) Google C++ coding standard, say “do not use unsigned … Continue reading

Posted in Programming | Comments Off on c and cpp pitfalls, mixing signed and unsigned integer, implicit conversion

compile c++ codes using Visual C++ Build Tools from the command prompt

Introducing the Visual Studio Build Tools “If you have installed Microsoft Visual C++ Build Tools 2015 on Windows 10, open the Start menu and choose All apps. Scroll down and open the Visual C++ Build Tools folder. Choose Visual C++ … Continue reading

Posted in Programming | Comments Off on compile c++ codes using Visual C++ Build Tools from the command prompt

Mibox 2 install youtube and play to kodi (just as chromecast)

1. install shafa TV manager and/or ES file explorer to be enable install apk from USB/SD card http://www.shafa.com/articles/yWNpNK6erhB6Q4dO.html 2. install Kodi/XMBC apk from shafa’s file manager (in toolbox) on USB storage 3. install apk of youtube for Google TV, and … Continue reading

Posted in Uncategorized | Comments Off on Mibox 2 install youtube and play to kodi (just as chromecast)

Evaluation of OpenFOAM on bash on Ubuntu on windows 10

## installation After Anniversary Build (2016 Aug) for x65 windows 10, it is possible to evaluate this beta feature in developer mode without upgrade to claimed unstable insider version. see detailed tutorial: To install ubuntu on windows 10 from power … Continue reading

Posted in Uncategorized | Comments Off on Evaluation of OpenFOAM on bash on Ubuntu on windows 10

disable windows input method hotkey

UPDATE: it seems the following methods still fails, as restart pc or windows update will invalidated the setting =========== Avoid the annoying hotkey to trigger the IME shape/punctation in Chinese for half/full see tutorial: http://superuser.com/questions/327479/ctrl-space-always-toggles-chinese-ime-windows-7 In addition to disapble Ctrl-Space, … Continue reading

Posted in Uncategorized | Comments Off on disable windows input method hotkey

Toshiba L650 laptop disassembling

I got a 5 year old laptop, it does not boot, no screen show, no beeping. So I need to disassemble and check. Generally, this laptop is easy to repalce harddisk or memory on the back.  And the dissabling is … Continue reading

Posted in Uncategorized | Comments Off on Toshiba L650 laptop disassembling

Introduction to Industrial IO (sensor framework for Linux)

introduciton to Industrial IO overview of industrial IO. In short, SPI and I2C sensor framework for Linux sensor categories: “ADC, DAC, light, accel(erometer), gyro, magnetometer, humidity, temperature, amplifier, frequency, orientation, health”, etc merged to mainline kernel 3.14, used by beagleBone, … Continue reading

Posted in Linux, Sensor | Comments Off on Introduction to Industrial IO (sensor framework for Linux)

A recommendation for free of charge 2D CAD and office system, also cross-platform

for office system, I recommend kingsoft  WPS office, which is based on Qt, much faster than java based solution. It has Android, Linux version in alpha, in addition to mature windows ‘s version http://wps-community.org/download.html For 2D CAD drawing, I recommend   … Continue reading

Posted in Linux | Comments Off on A recommendation for free of charge 2D CAD and office system, also cross-platform

Solve CFD via OpenFOAM in free CAx platform FreeCAD

Updated 2016-04-17 Boundary condition setup GUI has been done for preview This is an early preview, only for people with experience of OpenFoam. Test instruction could be found at https://github.com/qingfengxia/FreeCAD/ … /Readme.md I would love to see some feedback for … Continue reading

Posted in Linux, Programming, Research | Comments Off on Solve CFD via OpenFOAM in free CAx platform FreeCAD

Why power adapters for laptop are NOT compatible

see the word document contains figure to demonstrate various power adapters from diff manufacturers and how the claimed incompatible adapter could be reused. why laptop power adapter are not compatible and howto

Posted in Uncategorized | Comments Off on Why power adapters for laptop are NOT compatible

Using paraview to visualise vorticity (Lambda2, vorticity, Q-Criterion)

Please download the word document, which contains the details on setting up the Python Calculator filter to calc lambda2, and use the advanced option of ‘Gradient’ filter to calculate vorticity, Q-Criterion. This code is not tested, some user has already … Continue reading

Posted in Programming, Research | Comments Off on Using paraview to visualise vorticity (Lambda2, vorticity, Q-Criterion)

What is the max array size you can declare (big data challenge)

by Qingfeng Xia @ iesensor.com 2015 With the popularity of BIG DATA concept, have you think about what is the max data structure you can run?http://stackoverflow.com/questions/216259/is-there-a-max-array-length-limit-in-c

Posted in Programming | Comments Off on What is the max array size you can declare (big data challenge)

Ten things you must do after install Openwrt 15.05 on raspberry pi B

This is not a tutorial, but list some interesting things for Openwrt 2015-09-14 by Qingfeng Xia

Posted in Ineternet of Things, Linux | Comments Off on Ten things you must do after install Openwrt 15.05 on raspberry pi B