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The getSpatialData method

This method constructs and returns a specific 3D surface in a 2D array of type double . The surface is identified by the value of an incoming parameter named switchCase . There are 14 possible cases. The allowable values for switchCase range from 0 through 13 inclusive.

The other two input parameters specify the size of the surface that will be produced in units of rows and columns.

The code for the getSpatialData method

The getSpatialData method begins in Listing 14 .

Listing 14. Beginning of the getSpatialData method.
private static double[][]getSpatialData( int switchCase,int rows,int cols){double[][] spatialData =new double[rows][cols];switch(switchCase){

Listing 14 begins by creating a 2D array object of type double in which to store the surface.

Then Listing 14 shows the beginning of a switch statement that will be used to select the code to create a surface that matches the valueof the incoming parameter named switchCase .

Code and graphic output for fourteen example cases

Case 0

Listing 15 shows the code that is executed for a value of switchCase equal to 0.

Listing 15. Code for Case 0.
case 0: spatialData[0][0] = 1;break;

This case places a single non-zero point at the origin in the space domain. The origin is at the top-left corner. The surface produced by this case is shownin the leftmost image in Figure 5 . The non-zero value can be seen as the small white square in the top-left corner. In signal processing terminology,this point can be viewed as an impulse in space. It is well known that such an impulse produces a flat spectrum in wavenumber space.

Figure 5. An impulse in space.
missing image

The output surface

The rightmost image in Figure 5 shows the result of:

  • Performing a forward Fourier transform on the surface in the leftmost image
  • Performing an inverse Fourier transform on the complex wavenumber spectrum produced by the forward transform.

You can see the impulse as the small white square in the top-left corner of both images.

The wavenumber spectrum is flat

Because the wavenumber spectrum is flat, plots of the spectrum are completely featureless. Therefore, I did not include them in Figure 5 .

A very small error

The numeric output shows that the final output surface matches the input surface to within an error that is less than about one part in ten to thefourteenth power. The program produces the expected results for this test case.

If you were to go back to the equations in Listing 2 and Listing 3 and work this case out by hand, you would soon discover that the computationalrequirements are almost trivial. Most of the computation involves doing arithmetic using values of 1 and 0. Thus, there isn't a lot of opportunity forcomputational errors in this case.

Case 1

Now we are going to see a case that is more significant from a computational viewpoint. The input surface in this case will consist of a single impulse thatis not located at the origin in the space domain. Rather, it is displaced from the origin.

The wavenumber amplitude spectrum of a single impulse in the space domain should be flat regardless of the location of the impulse in the space domain.However, the real and imaginary parts of the wavenumber spectrum are flat only when the impulse is located at the origin in space.

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
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
Daniel
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Digital signal processing - dsp. OpenStax CNX. Jan 06, 2016 Download for free at https://legacy.cnx.org/content/col11642/1.38
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