difference between fprintf, printf, sprintf

http://stackoverflow.com/questions/4627330/difference-between-fprintf-printf-sprintf

fprintf writes formatted text to the output stream you specify.

printf is equivalent to writing fprintf(stdout, ...) and writes formatted text to wherever the standard output stream is currently pointing.

sprintf writes formatted text to an array of char, as opposed to a stream.

How to install Readline/libreadline in Ubuntu

Search different package

$ apt-cache search readline

http://linuxprograms.wordpress.com/2010/10/19/install-readline-linux/ 

Polynomial Order

The highest order power in a univariate polynomial is known as its order (or, more properly, its polynomial degree). For example, the polynomial

is of order , denoted .

Debugging in Octave

http://techlogbook.wordpress.com/2008/04/08/debugging-in-octave/


debug_on_warning(1);
debug_on_error(1);

this is to enter debug mode in Octave whenever a warning or error occurs.
To add a breakpoint, use
dbstop('yourfunctionname',1)
where 1 is the line number where you want to stop.
To go to next line, type
dbnext
To step into type
dbstep
To continue running, type
dbcont
to see the variable value, just type the name of the variable.

Dotfiles/Octave startup files and .octaverc templates

GNU Octave set PATH variable
http://bitonic.org/blog/?tag=octaverc

"can't open terminal"
Environment Setting?

http://osdir.com/ml/gnu.octave.maintainers/2005-04/msg00135.html

Octave documents
Startup files 
http://www.gnu.org/software/octave/doc/interpreter/Startup-Files.html

Another example
http://www.leancrew.com/all-this/2011/11/my-octaverc/


Keywords: dotfiles
http://dotfiles.org/

Escape Character:
In computing and telecommunication, an escape character is a character which invokes an alternative interpretation on subsequent characters in a character sequence.

http://en.wikipedia.org/wiki/Escape_character

Bash Initialization Files:
http://www.solipsys.co.uk/new/BashInitialisationFiles.html?HN0811

(Chinese link)
http://sns.linuxpk.com/home.php?mod=space&uid=55617&do=blog&id=16477
edit editor "gvim %s"
edit editor "xterm -e vim %s"
edit editor "gnome-terminal -e \"vim %s\""
edit editor "gedit %s"

set terminal foreground/background color

setterm -term linux -back blue -fore white -clear

http://superuser.com/questions/248299/how-to-change-background-foreground-color-on-all-existing-terminals

http://matt-linux-log.blogspot.com/2010/09/change-tty-text-and-background-colour.html 


Bash Prompt HOWTO
http://www.faqs.org/docs/Linux-HOWTO/Bash-Prompt-HOWTO.html


Well explanation on Colors & Prompts in BASH
http://systhread.net/texts/200703bashish.php



 Other references and resource
Xterm Control Sequences
http://invisible-island.net/xterm/ctlseqs/ctlseqs.html

Xterm
http://en.wikipedia.org/wiki/Xterm

Terminal Color configuration:
http://www.pixelbeat.org/docs/terminal_colours/


More Detail visual examples:
https://wiki.archlinux.org/index.php/Color_Bash_Prompt


Modified:

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
force_color_prompt=yes
 

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[32m\]\$

FPGA Design and Verification in Mechatronic Applications

VHDL-AMS


The System Designer’s Guide to VHDL-AMS: Analog, Mixed-Signal, and Mixed-Technology Modeling.


http://eetimes.com/design/automotive-design/4011419/Virtual-prototyping-boosts-model-driven-Design-for-Six-Sigma-methodology-Part-3-of-3--Design-example-Electronic-throttle-control


 

Multi-dimensional Fourier Transform and separability

http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/OWENS/LECT4/node2.html

Simple Separability Proof
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&ved=0CC0QFjAA&url=http%3A%2F%2Fwww.cs.unm.edu%2F~williams%2Fcs530%2Fft2d.pdf&ei=zN2rUMjxAa3biwKzuIDgCQ&usg=AFQjCNE7HhwvVkAK8c9JyjpWT0x8EIlJsA

N dimensional Fourier Transfrom (Stanford SEE)
n-dimensional Fourier Transform

Memory Organization and multi-dimensional logic

http://jemooo.com/memory-part-one/

Memory Organization:
www.cs.pitt.edu/~childers/CS1541/lectures/MemOrg.pdf
 

RAM Structure:
http://tams-www.informatik.uni-hamburg.de/applets/hades/webdemos/40-memories/40-ram/ram.html

Buffer

http://www.allaboutcircuits.com/vol_4/chpt_3/3.html

Wired logic connection

http://en.wikipedia.org/wiki/Wired_logic_connection

Dailly Reading: Open collector

Applications of open-collector devices

Because the pull-up resistor is external and need not be connected to the chip supply voltage, a lower or higher voltage can be used instead.

Open collector circuits are therefore sometimes used to interface different families of devices that have different operating voltage levels. The open-collector transistor can be rated to withstand a higher voltage than the chip supply voltage. Such devices are commonly used to drive devices such as Nixie tubes, and vacuum fluorescent displays which require higher operating voltages than the usual 5-volt logic supply.

 
Another advantage is that more than one open-collector output can connect to a single line.

If all outputs attached to the line are in the high-impedance state, the pull-up resistor will hold the wire in a high voltage(logic 1) state.

 If one or more device outputs are in the logic 0 (ground) state, they will sink current and pull the line voltage toward ground.


 
Open-collector devices are commonly used to connect multiple devices to a bus (i.e., one carrying interrupt or write-enable signals). This enables one device to drive the bus without interference from the other inactive devices - if open-collector devices are not used, then the outputs of the inactive devices would attempt to hold the bus voltage high, resulting in unpredictable output.

By tying the output of several open collectors together, the common line becomes a "wired AND" (positive-true logic) or "wired OR" (negative-true logic) gate.

  A "wired OR" behaves like the boolean OR for negative-true logic, where the output is LOW if any one of its inputs is low. Such circuit constructions are termed "wired-AND" and "wired-OR", 

Hardware Porting Solution:

SCSI-1 devices use open collector for electrical signaling. ^[1] SCSI-2 and SCSI-3 may use EIA-485.

SCSI Parallel Interface??

Dailly reading: Tri-state logic and high impedence

Three-state logic
http://en.wikipedia.org/wiki/Three-state_logic

high impedance:
http://en.wikipedia.org/wiki/High_impedance

Digital electronics
High Impedance: Low current, high voltage
Low Impedance: Low voltage, High current


In digital circuits, a high impedance (also known as hi-Z, tri-stated or floating) output is not being driven to any defined logic level by the output circuit. The signal is neither driven to a logical high nor low level; this third condition lead to the description "tri-stated". Such a signal can be seen as an open circuit (or "floating" wire) because connecting it to a low impedance circuit will not affect that circuit; it will instead itself be pulled to the same voltage as the actively driven output. The combined input/output pins found on many ICs are actualy tri-state capable outputs which have been internally connected to inputs. This is the basis for bus-systems in computers, among many other uses.

The high-impedance state of a given node in a circuit cannot be verified by a voltage measurement alone. 

A pull-up resistor can be used to try to pull the wire to high and low voltage levels. If the nodes is not in a high-impedance state, extra current from the resistor will not significantly affect its voltage level.


Analog electronics:
The high impedance node is one that does not have any low impedance paths to any other nodes.

Three-state logic
3 state logic allows an output port to assume a high impedance state, effectively removing the output from the circuit. This allows multiple circuits to share the same output line or lines.

Such as a bus which cannot listen to more than one device at a time.

Active low (OE output enable) which dictates whether the outputs should be held in high-impedance state or drive their respective loads (to either 0- or 1-level)


The whole concept of the third state is to effectively remove the device's influence from the rest of the circuit. If more than one device is electrically connected, putting an output into the Hi-Z state is often used to prevent short circuits, or one device driving high (logic 1)  against another device driving low (logical 0).

In particular, they are essential to the operation of a shared electronic bus.

Output enable vs. chip select

If CS is not asserted, the outputs are high impedance.
The difference lies in the time needed to output the signal. When chip select is deasserted, the chip does not operate internally, and there will be a significant delay between providing an address and receiving the data (An advantage of course, is that the chip consumes minimal power in this case.)

When chip select is asserted, the chip internally performs the access, and only the final output drivers are disabled by deasserting output enable. This can be done while the bus in use for other purposes.

Circuit designers will often use pull-up or pull-down resistors (usually within the range of 1-100kohm) to influence the circuit when the output is tri-stated. For example, I2C bus protocol (a bi-directional communication bus protocol often used between devices) specifies the use of pull-up resistors on the two communication lines. When devices are inactive, they "release " the communication lines and tri-state their outputs, thus removing their influence on the circuit. When all the devices on the bus have "released" the communication lines, the only influence on the circuit is the pull-up resistors, which pull the lines high. When a device wants to communicate, it comes out of the Hi-Z state and drives the line low. Devices communicating using this protocol either let the line float high, or drive it low-- thus preventing any bus contention situation where one device drives a line high and another low.


The PCI local bus provides pull-up resistors, but they would require several clock cycles to pull a signal high given the bus's large distributed capacitance. To enable high-speed operation, the protocol requires that every device connecting to the bus drive the important control signals high for at least one clock cycle before going to the Hi-Z state. This way, the pull-up resistors are only responsible for maintaining the bus signals in the face of leakage current.


Hardware configuration solution:

A three-state bus is typically used between chips on a single printed circuit board (PCB), or sometimes between PCBs plugged into a common backplane.

An open-collector bus is often used between PCBs plugged into a common backplane, or connected over longer cables.

How to grep word

http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_04_02.html

If you want to get a list of all five-character English dictionary words starting with "c" and ending in "h" (handy for solving crosswords):

cathy ~> grep '\<c...h\>' /usr/share/dict/words
catch
clash
cloth
coach
couch
cough
crash
crush

For matching multiple characters, use the asterisk. This example selects all words starting with "c" and ending in "h" from the system's dictionary:

cathy ~> grep '\<c.*h\>' /usr/share/dict/words
caliph
cash
catch
cheesecloth
cheetah
--output omitted--

vimdiff Tutorial

http://amjith.blogspot.com/2008/08/quick-and-dirty-vimdiff-tutorial.html

• If you load up two files in splits (:vs or :sp), you can do :diffthis on each window and achieve a diff of files that were already loaded in buffers
• :diffoff can be used to turn off the diff mode.

How to use non-blocking sends and receives to great effect

http://www.cs.ucsb.edu/~hnielsen/cs140/mpi-deadlocks.html

The send and receive calls are almost exactly the same as the blocking versions, with two differences. The first (which is conceptually important) is that the function will return immediately, regardless of whether the send or receive has finished. The second (which is important for the implementation) is that they take an MPI_Request pointer as the final parameter. This is later used to verify that the send or receive has been completed by calling MPI_Wait().


It is important to note that you can use any combination of blocking and non-blocking receives! 

Concept: Race Condition

electronics 
Computing
Filesystem

http://en.wikipedia.org/wiki/Race_condition

Summary

• Use the calls MPI_Isend() or MPI_Irecv() to initiate a non-blocking transfer.
• Always include an MPI_Wait() after a non-blocking call. The buffer you specified in the send or receive doesn't contain modifiable (in the case of sending) or even readable data (in the case of receiving) until this call completes.
• You can use a non-blocking call with a blocking call. Most of the example code does this.
• Be very careful about race conditions in the data. Don't write to data that is being sent, and don't read or write to data that is being received.

Dailly Reading: Asynchronous_I/O (wiki)

http://en.wikipedia.org/wiki/Asynchronous_I/O

Asynchronous I/O (non-blocking I/O),

Keywords/Concept map:

Hardware device status polled
hardware interrupts
Multitasking operating systems
Spooling?
multithreading

Forms:
All forms of asynchronous I/O open applications up to potential resource conflicts and associated failure. Careful programming often using
mutual exclusion, semaphores, etc)


Signals (Interrupts)
Available in BSD and POSIX Unix. I/O is issued asynchronously, and when it is complete a signal (interrupt) is generated. As in low-level kernel programming, the facilities structures as seen by the signal handler. The signal handler is usually not able to issue further asynchronous I/O by itself.


 
IO Synchronous Asynchronous Blocking IO Non Blocking IO (In chinese) http://blog.csdn.net/historyasamirror/article/details/5778378

Richard Stevens:
Unix Network Programming Volume 1, Third Edition: The Sockets Networking.

Section 6.2 I/O Models

Reducing Thermocouple Noise to Improve Measurements (NI)

http://digital.ni.com/public.nsf/allkb/9B99C4C98952F38486256298005A236D



Field Wiring and Noise Considerations for Analog Signals
http://www.ni.com/white-paper/3344/en

Thermocouples Vs. Thermistors (Temperature Measurement)

http://www.veriteq.com/validation/thermocouples-vs-thermistors.htm

Measuring Temperature: Managing Errors & Calibration:

Signal Errors & Noise

assert() Function Example Program in C

http://www.java-samples.com/showtutorial.php?tutorialid=595

The macro assert() can diagnose program bugs. It is defined in ASSERT.H, and its prototype is

 The argument expression can be anything  you want to test-a variable or any C expression. If expression evaluates to TRUE, assert() does nothing. If expression evaluate to FALSE, assert() displays an error message on stderr and aborts program execution.

How do you use assert()? It is most frequently used to track down program bugs (which are distinct from compilation errors). A bug doesn't prevent a program from compiling, but it causes it to give incorrect results or to run improperly (locking up, for example).


Analysis:

The action of assert() depends on another macro named NDEBUG (which stands for "no debugging"). If the macro NDEBUG isn't defined (the default), assert() is active. If NDEBUG is defined, assert() is turned off and has no effect. If you placed assert() in various program locations to help with debugging and then solved the problem, you can define NDEBUG to turn assert() off. This is much easier than going through the program and removing the assert() statements (only to discover later that you want to use them again). To define the macro NDEBUG, use the #define directive. You can demonstrate this by adding the line

#define NDEBUG

Note that NDEBUG doesn't need to be defined as anything in particular, as long as it's included in a #define directive.

Intracommunicator and MPI_COMM_WORLD

http://static.msi.umn.edu/tutorial/scicomp/general/MPI/content_communicator.html

• MPI_COMM_WORLD is the initially defined universe intracommunicator for all processes to conduct various communications once MPI_INIT has been called.
• In MPI-1, where the processes of executing the MPI computation, MPI_COMM_WORLD is a communicator of all processes available for the computation. This communicator has the same value in all processes.
• In MPI-2, where processes can dynamically join an MPI execution, it may be the case that a process starts an MPI computation without having access to all other processes. In such situations, MPI_COMM_WORLD is a communicator incorporating all processes with which the joining process can immediately communicate. Therefore, MPI_COMM_WORLD may simultaneously have different values in different processes

SPMD

We compiled a single program -- we didn't compile a different program for each process-- and we did this in spite of the fact that process 0 is doing something fundamentally different from the other process. This is quite common in parallel programming. In fact, most MPI programs are written in this way. That is, single program is written so that different processes carry out different actions, and this is achieved by simply having the processes branch on the basis of their process rank. (SPMD) Single Program multiple data.


--An introduction to Parallel Programming,
Peter S. Pacheco
University of San Francisco

Extreme programming

Extreme Programming (XP) is a software development methodology which is intended to improve software quality and responsiveness to changing customer requirements. As a type of agile software development,^[1][2][3] it advocates frequent "releases" in short development cycles (timeboxing), which is intended to improve productivity and introduce checkpoints where new customer requirements can be adopted.


Other elements of Extreme Programming include: programming in pairs or doing extensive code review, unit testing of all code, avoiding programming of features until they are actually needed, a flat management structure, simplicity and clarity in code, expecting changes in the customer's requirements as time passes and the problem is better understood, and frequent communication with the customer and among programmers.^[2][3][4] The method takes its name from the idea that the beneficial elements of traditional software engineering practices are taken to "extreme" levels, on the theory that if a little is good, more is better.^{[clarification needed]}
------Wiki

Ubuntu 12.04 cannot login, bounces back to login splash

actionparsnip (andrew-woodhead666) said on 2012-05-16:

#2

Press CTRL+ALT+F1 and log in there and run:

sudo chown -R $USER:$USER $HOME

Then press CTRL+ALT+F7 and try to log in