Re: Octave Activation Key
Asela Buchheit
In music, an octave (Latin: octavus: eighth) or perfect octave (sometimes called the diapason)[2] is the interval between one musical pitch and another with double its frequency. The octave relationship is a natural phenomenon that has been referred to as the "basic miracle of music", the use of which is "common in most musical systems".[3] The interval between the first and second harmonics of the harmonic series is an octave.
To emphasize that it is one of the perfect intervals (including unison, perfect fourth, and perfect fifth), the octave is designated P8. Other interval qualities are also possible, though rare. The octave above or below an indicated note is sometimes abbreviated 8a or 8va (Italian: all'ottava), 8va bassa (Italian: all'ottava bassa, sometimes also 8vb), or simply 8 for the octave in the direction indicated by placing this mark above or below the staff.
Most musical scales are written so that they begin and end on notes that are an octave apart. For example, the C major scale is typically written C D E F G A B C (shown below), the initial and final C's being an octave apart.
Because of octave equivalence, notes in a chord that are one or more octaves apart are said to be doubled (even if there are more than two notes in different octaves) in the chord. The word is also used to describe melodies played in parallel one or more octaves apart (see example under Equivalence, below).
Octaves are identified with various naming systems. Among the most common are the scientific, Helmholtz, organ pipe, and MIDI note systems. In scientific pitch notation, a specific octave is indicated by a numerical subscript number after note name. In this notation, middle C is C4, because of the note's position as the fourth C key on a standard 88-key piano keyboard, while the C an octave higher is C5.
The notation 8a or 8va is sometimes seen in sheet music, meaning "play this an octave higher than written" (all' ottava: "at the octave" or all' 8va). 8a or 8va stands for ottava, the Italian word for octave (or "eighth"); the octave above may be specified as ottava alta or ottava sopra). Sometimes 8va is used to tell the musician to play a passage an octave lower (when placed under rather than over the staff), though the similar notation 8vb (ottava bassa or ottava sotto) is also used. Similarly, 15ma (quindicesima) means "play two octaves higher than written" and 15mb (quindicesima bassa) means "play two octaves lower than written."
The abbreviations col 8, coll' 8, and c. 8va stand for coll'ottava, meaning "with the octave", i.e. to play the notes in the passage together with the notes in the notated octaves. Any of these directions can be cancelled with the word loco, but often a dashed line or bracket indicates the extent of the music affected.[4]
After the unison, the octave is the simplest interval in music. The human ear tends to hear both notes as being essentially "the same", due to closely related harmonics. Notes separated by an octave "ring" together, adding a pleasing sound to music. The interval is so natural to humans that when men and women are asked to sing in unison, they typically sing in octave.[5]
Octave equivalence is a part of most advanced[clarification needed] musical cultures, but is far from universal in "primitive" and early music.[7][failed verification][8][clarification needed] The languages in which the oldest extant written documents on tuning are written, Sumerian and Akkadian, have no known word for "octave". However, it is believed that a set of cuneiform tablets that collectively describe the tuning of a nine-stringed instrument, believed to be a Babylonian lyre, describe tunings for seven of the strings, with indications to tune the remaining two strings an octave from two of the seven tuned strings.[9] Leon Crickmore recently proposed that "The octave may not have been thought of as a unit in its own right, but rather by analogy like the first day of a new seven-day week".[10]
The canonical way to create a function in both octave and matlab is by placing it in a dedicated file by the same name, and starting the file with a function declaration. The corollary of this is that any file in the path that starts with a function declaration is detected at start-up and made available to the user as a callable function.
Octave has supported 'on-the-go' function definitions for many years (and in fact also supports subsequent 'exporting' of such 'on-the-go' functions to files); matlab has only included 'on-the-go' functionality very recently (2016b I believe?), and has chosen to implement this somewhat differently than octave, ( presumably to keep octave on its toes? :p )
Matlab's recent implementation effectively breaks this functionality / paradigm. To see what I mean, copy paste your code above into a fresh terminal (or highlight then press F9) and watch it break. A script is no longer copy/pasteable, but assumes matlab will read ahead and load up any function definitions first, and then go back and try to run the remaining commands; in other words, matlab now kinda treats scripts like it does its functions. Note that matlab still also requires a script to start with a non-function-declaration statement, so effectively this bit is the same as octave needing to start with a '1'. The only thing that's changed is this look-ahead behaviour for preemptively loading 'on-the-go' functions, which I would argue isn't necessarily a good thing in the context of scripts.
More warnings appear if I click and drag the plot or even mouse-over it. If I then try to add an xlabel or title, I get a segfault and octave quits. The default graphics_toolkit is fltk, which I found by starting octave and running
Then the plot works, and only the bounding box warning shows up, and I can add labels etc. In other words, the same behaviour as gnuplot. In fact, the plot looks more like a gnuplot one than an fltk one (judging by the buttons along the bottom). But if I start octave and try this:
I'd like to use the octave mode for emacs. There is no octave-mode package in MELPA, but EmacsWiki ( ) and the emacs manual seem to suggest that it is built-in for v21 and higher (I have v28). However, simply opening a .m file does not activate it.
Octave is called quietly by means of "System Exec.vi" in "octave_exec.vi". Usually Octave creates a lot of stdout output when starting. To remove unwanted output, you can apply filter keyword, and only stdout output after the keyword will be returned. See a "multiply.m" Octave script. Octave errors are parsed in a simple way to create LabVIEW error, Octave warnings are ignored. In the case of error, call string of Octave is sent to the error description, so you can copy it and test it manually from windows console.
basically,i have downloaded the octave using the link you provided then the two V.Is that you have given and the multiply.m.i have put these 3 files in the same folder.i run test octave.vi and i get 0 as result stderr returns empty string,hence no error returns..Am thinking,since you have already tested it then this means that I am doing something wrong,if you can just give me some suggestions on what you think i could be doing wrong that might help me figure it out,,,i use windows Xp..i have trired setting changing result=value1.*value2 in .m file and setting result=2 and hence expecting that when i run test octave i will get a 2 as the result but it returns 0..(with no error returns)
And the GNU Octave is working? Did you tried to run octave separately from Labview and tested the multiply.m? The vi does nothing more than calling octave from commandline. I have tested it in winxp, unfortunately every windows OS is behaving slightly differently, and some errors shows up on stderr, but some errors shows only in stdout. Switch off the filter key and look at the full output of the command line. You can also take a look, what command is sent to System Exec.vi and try the command yourself in window command line.
awesome..i have run octave alone and that's when i figured out why i was getting the zero..basically value1 and value2 are passed from test octave.vi as floating points in string form,hence the 3 and 4 are passed as 3,0 and 4,0 respectively however multiply.m receives the the two variables as multiply(3,0,4,0) and since it's expecting only two variables it seems to me like it will pick the fast two numbers (in this case 3 and 0) and hence return the result as zero ...thank you very much
Anyway I am working on better solution using pipes. Pipes in windows are a pain, however it already works. With this solution the octave functions as some instrument. You initialize, send commands, reads variables etc. Unfortunately it is not yet finished.
2, Through special pipe. This is method I am using in new version of labview-octave interface, however it is quite complicated under windows (and very simple under linux if you use it). With this, you can directly write commands into octave and read out values.
3, Save data to file, load file in matlab. E.g. in octave you can save to csv. Or you can also find VI's for saving and reading data in Matlab's binary format. Octave can read or write into binary format.
As I said you can do it with method 2: you can create a new pipe to octave. And this is complicated under windows. You cannot use a simple routine such as system exec. You need to call windows api to create a new pipe to octave, open this pipe in labview and from labview read out a value of result. You do not have to add a printf to your function.
Hi kaero,i am using a v.i which makes more than one call to octave through system Exec.vi,however the actual launching of octave seems to takes some time and therefore increasing the total time it takes to execute this v.i,,,do you know of anyways of making the launching of octave when called by labview faster?
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