The following packages have been kept back

If the upgrade would require another package to be deleted, or a new package to be installed, the package will be “kept back.” As the man page for apt-get upgrade explains:

Packages currently installed with new versions available are retrieved and upgraded; under no circumstances are currently installed packages removed, or packages not already installed retrieved and installed.



Just do

sudo apt-get install linux-headers-server linux-image-server linux-server

and you will be fine.

Doing "apt-get dist-upgrade" will upgrade your OS to a new version which is often what people do not want.


Mesh Basis: manifold mesh


In a “manifold” vertex, the outer edges form a closed loop, thus posing no problems to the mesh quality (Left). With a ” non-manifold” vertex, the outer edges do not form a closed loop, acting as a barrier in the free domain (Right)


How to highlight and copy text on sites that block it

Every now and then I come across sites on the Internet that prevent you from copying some or all of the text displayed to the clipboard, or even selecting it in first place using the mouse or keyboard.

I noticed this on a bank’s site recently for example where I was not allowed to copy the bank account number to the clipboard.

This guide looks at methods to overcome the limitation put in place by websites on the Internet. But first, why do sites implement these restrictions in first place?

While reasons are provided by companies and individuals who implement the functionality on their web properties, the most likely reason is some form of copy protection.

Method 1: Turn off JavaScript


Most websites use JavaScript to block mouse functionality. If you turn off JavaScript on the site temporarily or even permanently, you will be able to copy text displayed on it using the mouse.

Some websites rely on JavaScript on the other hand which means that you may run into issues doing so. Some may even refuse to display at all when JavaScript is turned off.

  • Firefox users can press F12, there on the upper right preferences icon to disable JavaScript in the menu that opens.


  • Chrome users can disable JavaScript in the Content settings: chrome://settings/content
  • Internet Explorer users can turn off JavaScript in Internet Option > Security > Zone > Custom Level > Active Scripting
  • Opera users can disable JavaScript under Websites in the Opera settings: opera://settings/

Extensions like NoScript can be useful in this regard as they block the execution of scripts as well.

Method 2: The source


Another option that you have is to display the source code of the website you are on. Since it is displayed in a plain text editor it is possible to copy anything from it without restriction.

Simply press Ctrl-u while you are on the site to display its source code. This works in most browsers including Firefox, Chrome and Internet Explorer.

It is still necessary to find the text or content that you are looking for in the source. Use Ctrl-f to jump directly to it.

There you may also find links to images and other contents that you could not save or copy.

Method 3: Extensions and scripts

The third and final option is most suitable if you encounter sites regularly that prohibit right-click use or text copying when you are on them, and if the methods outlined above don’t work or are not really suitable.

RightToClick for Firefox disables JavaScript annoyances such as forbidding right-clicks or text selection on sites.

RightToCopy for Chrome offers similar features.

You find numerous extensions for these two browsers that remove annoyances on websites.

Originally from

Vector Outer Product

Vector outer product is denoted by Outer Product or Outer Product . Vector outer product is also called vector matrix product because the result of the vector multiplication is a matrix. It can only be performed for two vectors of any size, not necessarily the same size.

Algebraically, the vector outer product is a multiplication of a column vector by a row vector Outer Product to obtain a matrix provided by the formula below

Outer Product
Suppose we have Outer Product and Outer Product , the vector outer products are
Outer Product
Outer Product


Some important properties of vector outer product are

  • Vector outer product is a not commutative operation. If you reverse the order you will get different result and even different size Outer Product .
  • If matrix is the results of a vector product Outer Product then multiplication of that matrix with the second factor produces a vector of the first factor scaled by the square norm of the second factor Outer Product .

Originally from

Using LaTeX in supports \LaTeX, a typesetting system that’s really good at formatting mathematical formulas and equations.

To type a formula in WordPress type

< Your LaTex code> without the signs < and >.


Note that there is no white space between ‘$’ and keyword ‘latex’!

To display a formula type

$ latex \displaystyle $

For example <p align=”center”>$ latex \displaystyle \sum_{n=1}^\infty \frac{1}{n^2} = \frac{\pi^2}{6}. $</p> yields (remember to replace ”  with ”)

\displaystyle \sum_{n=1}^\infty \frac{1}{n^2} = \frac{\pi^2}{6}.

i\hbar\frac{\partial}{\partial t}\left|\Psi(t)\right>=H\left|\Psi(t)\right>

Rigging & Skinning

Rigging & Skinning

use data-driven methods to analyze the geometry data or features from handcrafted animation by animators or dynamic simulation,  and then implement interactive skinning.

1. Efficient Dynamic Skinning with Low-Rank Helper Bone Controllers

math method:
Introduction: State-Space Methods for Controller Design

2. Real-time Skeletal Skinning with Optimized Centers of Rotation

3. On Linear Variational Surface Deformation Methods

4. Linear Subspace Design for Real-Time Shape Deformation  ( with source code )

Dynamic harmonic fields for surface processing ( with source code )
Siggraph :
1. Skinning: Real-time Shape Deformation

1. Siggraph course
Skinning: Real-time Shape Deformation

2. Geometry Processing Algorithms cs468 – Spring 2012

3. Data-Driven Shape Analysis

4. CSCI 599: Digital Geometry Processing

5. 524 Computer Graphics: Modeling

6. CS 294-74Mesh Generation and Geometry Processing in Graphics, Engineering, and Modeling

7. The Discrete Differential Geometry Forum

1. deformation review

People & Lab
3. (Interactive Geometry Lab)

1. Libigl is an open source C++ library for geometry processing research and development
2. gptoolbox – Geometry Processing Toolbox
3. Vega FEM Library

Polygon Mesh Processing Mario Botsch 2010

Originally posted in