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Nella computer grafica interattiva, punti e vettori sono rappresentati in coordinate omogenee mediante array di quattro elementi, e tutte le trasformazioni geometriche (traslazioni, rotazioni, scalamenti, proiezioni) sono realizzate con prodotti matrice-vettore.

Prodotto matrice-vettore

L'inversione tra elementi di posto pari ed elementi di posto dispari mediante prodotto matrice-vettore è illustrata dalcodice int DIM = 4; float[][] myMatrix = {{0, 1, 0, 0}, {1, 0, 0, 0}, {0, 0, 0, 1}, {0, 0, 1, 0} }; float[] myVector = {0.1, 0.2, 0.3, 0.4}; float[] newVector = new float[4]; for (int i=0; i<DIM; i++) for (int j=0; j<DIM; j++) newVector[i] += myMatrix[i][j] * myVector[j]; println(myVector); println(); println(newVector);

Come è fatta la matrice che, pre-moltiplicata per un array, ne ruota circolarmente di una posizione gli elementi?

0 1 0 0 0 0 1 0 0 0 0 1 1 0 0 0 Una matrice fatta così è un caso particolare di matrice circolante .

Many-to-many mapping

In molte applicazioni di interaction design (si veda, ad esempio, il caso della interactive sonification ), ci si trova a dover mappare una molteplicità di variabili, il cui valore può venire dallalettura di sensori, in una molteplicità di parametri algoritmici. Spesso tale mapping è lineare ed esprimibilecon un prodotto matrice-vettore. Ad esempio, distanza, velocità, e temperatura si possono mappare in posizione, colore, e frequenza di oscillazione di un oggetto grafico, in maniera che, ad esempio, il colore dipenda da una combinazione divelocità e temperatura. Il funzionamento delle Mixing Console si può interpretare come mapping multivariato lineare degli ingressi nelle uscite.Purtroppo, molti mapping di interesse sono non-lineari, e non esprimibili mediante prodotto matrice-vettore. Adesempio, la trasformazione delle coordinate di rappresentazione dei colori da RGB a HSB è non lineare.


Si legga la sezione Multi-Dimensional Arrays di Data Structures and Algorithms with Object-Oriented Design Patterns in Java o, ancor meglio, la sezione Multi-Dimensional Arrays di Introduction to Programming Using Java .


Gli array soffrono di due limitazioni principali:

  • la loro occupazione di memoria va pre-impostata;
  • gli indici sono obbligatoriamente numeri interi.
Quando si parla di mappe, in ambito delle strutture dati, ci si riferisce di solito a strutture più generali, la cuidimensione è dinamicamente allocabile, e nelle quali l'accesso agli elementi può avvenire attraverso oggetti di tipoarbitrario, chiamati key (chiave).


Si legga il capitolo 19 di How to Think Like a Computer Scientist

Matrici nel physical computing

Nel progetto WAV , la classe Matrix per l'ambiente Wiring di physical computing è stata usata per pilotare una matrice di LED a 8 righe e 16colonne per mezzo di un paio di chip MAXIM MAX7219 . Supponiamo per semplicità di dover gestire una matrice a 8 righee 8 colonne per mezzo di un solo chip MAX7219 e di voler propagare una cresta d'onda da sinistra a destra. La matriceviene dichiarata e istanziata come Matrix myMatrix = Matrix(0, 2, 1); Si può predisporre un array bidimensionale di bit 8x8 medianteistanziazione della classe Sprite : Sprite wave = Sprite( 8, 8,b10000000, b10000000,b01000010, b01000010,b00100100, b00100100,b00011000, b00011000,); e scrivere una funzione da eseguirsi a clockrate void loop() {myMatrix.write(i, 1, wave); // place sprite on screen (i is an int) delay(1000); // wait a little bitmyMatrix.clear(); // clear the screen for next animation framei = 1 + (i+1)%8; // circular (between 1 and 8) increment of i } oppure, alternativamente, procedere direttamente alla scrittura ciclica void loop() {myMatrix.clear(); // clear displaydelay(1000);// turn pixels on (i is an int that is forced to stay between 0 and 7) // decreasing rampmyMatrix.write(1, 1+(i)%8, HIGH); myMatrix.write(2, 1+(i)%8, HIGH);myMatrix.write(3, 1+(i+1)%8, HIGH); myMatrix.write(4, 1+(i+1)%8, HIGH);myMatrix.write(5, 1+(i+2)%8, HIGH); myMatrix.write(6, 1+(i+2)%8, HIGH);myMatrix.write(7, 1+(i+3)%8, HIGH); myMatrix.write(8, 1+(i+3)%8, HIGH);// increasing ramp myMatrix.write(3, 1+(i+6)%8, HIGH);myMatrix.write(4, 1+(i+6)%8, HIGH); myMatrix.write(5, 1+(i+5)%8, HIGH);myMatrix.write(6, 1+(i+5)%8, HIGH); myMatrix.write(7, 1+(i+4)%8, HIGH);myMatrix.write(8, 1+(i+4)%8, HIGH); i++;}

Questions & Answers

do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Mueller Reply
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Source:  OpenStax, Programmazione di artefatti interattivi. OpenStax CNX. Dec 09, 2010 Download for free at http://cnx.org/content/col10417/1.9
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