Not necessarily Java related, more a general programming issue I have come a long and I am currently using java to mock up a project that will eventually get moved over to C++.
I am trying to implement FFT Convolution into a java project and have things partially working, I do not know if it is a coding issue, logic issue or if I simply know nothing of FFT and convolution.
For starters I got an FFT library that I do have working, if I create a small array pass it into the forward FFT, do a little bit of bit manipulation (converting a complex array of size n*2 into a re[] and im[] of size n), run the inverse FFT and do the same bit manipulation again I get back where I started.
However if I take two arrays, a Dirac Delta function (an array with a 1 followed by zeros for the rest of the array) and a stepping kernel (ex. {1, 2, 3, 4 etc}), I would expect to get the forward FFT of both arrays, bit manipulation, multiply them together, Inverse FFT, and bit manipulate again and the result would be the kernel. I have not had such luck.
This is the gist of the program:
// bit manipulation, converts complex array to two re and im arrays
public void bitTwiddle(double [] real, double [] real2, double [] imaginary){
for (int idx = 0; idx < (N * 2); idx++){
realCopy[idx] = real [idx];
[Code] ....
This is the result:
Quote
=====================================================================
Dirac Delta In Time Domain:
Real:1.000.000.000.00
Imag:0.000.000.000.00
=====================================================================
Dirac Delta Frequency Domain
Real:0.500.500.500.50
Imag:0.000.000.000.00
=====================================================================
Kernel In Time Domain
Real:1.002.003.004.00
Imag:0.000.000.000.00
=====================================================================
Kernel In Frequency Domain
Real:5.00-1.00-1.00-1.00
Imag:0.00-1.000.001.00
=====================================================================
Result: Dirac Delta x Kernel
Real:2.50-0.50-0.50-0.50
Imag:0.00-0.000.000.00
=====================================================================
Result In Time Domain
Real:0.501.501.501.50
Imag:0.000.000.00-0.00
I implemented the gray scale filter and the convolution filter . If I apply before the grayscale filter convolution and then I can not see the picture, I see pretty much the JPanel that should contain the image. The two filters separately functioning correctly
Code filter grey scale
public BufferedImage greyScale(BufferedImage originalImage) { BufferedImage destImg = new BufferedImage(originalImage.getWidth(), originalImage.getHeight(), BufferedImage.TYPE_INT_ARGB); int alpha, red, green, blue; for (int x = 0; x < originalImage.getWidth(); x++) { for (int y = 0; y < originalImage.getHeight(); y++) { int pixel = originalImage.getRGB(x, y);
I have to implement all the stack methods in java such as push, pop empty, not using the ready methods but have to create them and to execute an exercise but is sth wrong with it
public class Stiva { /** the problem is here how to declare the stack 1 and stack 2 and kreu(head) gjmax(size)*/ int Gjmax; int array[] = new int[Gjmax]; int kreu; private Stiva stiva1; private Stiva stiva2;
I have to implement all the stack methods in java such as push, pop empty, not using the ready methods but have to create them and to execute an exercise but something wrong with it....
public class Stiva { /** the problem is here how to declare the stack 1 and stack 2 and kreu(head) gjmax(size)*/ int Gjmax; int array[] = new int[Gjmax]; int kreu; private Stiva stiva1; private Stiva stiva2;
What would be the most effective method to display data grabbed from a web source that is queried every second, for example the most recent EUR/USD price?
I already have access to the data stream, and I've built a simple FXML in javaFX that contains a grid; I'm not sure how to approach putting the live ticking data into the grid so it continues to update as the price changes, for example.
I want to use graphs in java. Is there any class in java for implementation of graph theory? I most create a graph and run DFS(Depth First Search) algorithm on that.
1. In jsp 1 , i have 3 checkboxes(chkbox1,chkbox2,chkbox3) , if i select check boxes (chkbox1, chkbox2), and click on submit, corresponding two text fields (chkbox1,chkbox2) will have to appear in the next jsp i.e., jsp 2.
2. In jsp 1 , i have 3 checkboxes(chkbox1,chkbox2,chkbox3) , if i select check boxes (chkbox2, chkbox3), and click on submit, corresponding two text fields(chkbox2,chkbox3) will have to appear in the next jsp i.e., jsp 2.
Like this, which ever checkbox i select, corresponding text fields should appear in the subsequent jsp.
In the above program even if i comment out the Hashcode method , i believe it is still taking the memory address values from the native hashcode method of Object class. but the equals override implentation says that i have two insertions which are same . So as per my logic it should not allow the duplicate element to enter.but its not so ...the duplicate element is well inserted without hashcode .
How to implement GridLayout. In my applet, I want to make a grid of 2 rows and 2 columns. In each grid I want to add a Label and a TextField. I want the background to be red.
So my code would be?
import java.awt.*; import java.applet.*; import java.awt.event.*; public class GridLayoutApplet extends Applet implements ActionListener{ // construct components Label fNameLabel = new Label("First Name"); TextField fNameField = new TextField(20);
[Code] .....
I have read about panels and frames but, it is all confusing to me. How can you add a label and a TextField to one square of the grid?
Something about implementing Comparator interface isn't very clear to me: overriding the compare method.
Like here for example:
//This sorts a list of objects holding information based on age: the name and the age of the person
public class Person { String name; int age; public Person (String name, int age) { this.name = name; this.age = age;
[Code] ....
What exactly is happening behind the scenes? I don't understand mostly the part where it returns a 0, a 1, or a -1. After it returns one of those values, what really happens next?
For the displaying of the list, is the method toString() being accessed to output the list in the System.out.println statement?
The following codes shows an implementation of an enqueue function of a FIFO immutable queue, and the output result shows the String "c".
I don't understand why since I expected it should be null.
The head and the tail of an ImmutableQueue Object are two separate queue, and each time I call the enqueue function, it just return a new object with a new tail, however, the head is not modified except the first two times I call the function.
Therefore, I expected head.next.next should be a null element, but the result is not like that.
public class ImmutableQueue<E> { private int size =0; public Queue<E> head; public Queue<E> tail; public ImmutableQueue(){} private ImmutableQueue(Queue<E> hd, Queue<E> tl){ head=hd; tail=tl;
I want to implement new locking mechanism similar to like how threads locking or synchronized does the operation. Any inputs to implement out own locking mechanism ?
I am in the process of implementing Priority queue, as I understand that there are many data structures you could use to implement. I implemented it with the an array, which it works absolutely fine. However I have limitations on what collections I can use from the collections classes. I fact I cant use any of the collections classes. Meaning I cant use array.
I’m trying to implement Priority Queue using heap. And implementing heap using binary trees. But however I have a few questions which I need to clarify and I cant think of any other way of resolving it. Ofcourse I can implement my own simple array class using linked list.
Inserting into heap would be quite simple, as I just need to find the right last position from left to right leaf to insert the node into the tree. However after inserting, you may want to make sure that leaf node values are > than root node. Therefore, the root node will always be with the highest priority.
I call these steps where you compare from top down as bubbledown and bubbleup. To do this I really need a for each node within the treee node to have attribute pointing to its root node. So in case of bubbleup I always have a pointer for a given node to its root, without it would mean I would to traverse through the entire tree to identify its root. Which I believe is very inefficient.
Or have I taken this completely wrong? Or is it the case that heap are only best with arrays and therefore use array (by implement it using linked list?)
I have to write a code for File Transfer Protocol! It says that I only need to write code for client, but it also says that I have to run the program and send some files to server. I guess than I also need server side as well. I have to write my own classes, I cannot import some existing classes. I have to connect to the server with password and username and after that send some files to the server. I don't know anything about FTP. Can i maybe do this by Sockets and ports? I worked something with that.
The following codes shows an implementation of an enqueue function of a FIFO immutable queue, and the output result shows the String "c". I don't understand why since I expected it should be null.
The head and the tail of an ImmutableQueue Object are two separate queue, and each time I call the enqueue function, it just return a new object with a new tail, however, the head is not modified except the first two times I call the function.
Therefore, I expected head.next.next should be a null element, but the result is not like that.
public class ImmutableQueue<E> { public Queue<E> head; public Queue<E> tail; public ImmutableQueue(){} private ImmutableQueue(Queue<E> hd, Queue<E> tl){ head=hd; tail=tl;
I am currently writing the Quick Sort implementation where the pivot is chosen to be the medianOf3 element in the sub array. The program should output the total number of comparisons (excluding the ones needed to compute the median itself).I cannot spot any mistake anywhere - yet I am getting the wrong output in the end.
Input file (100.txt) attached. Current output: 513. Correct output: 518. Where are the missing 5 comparisons? />
I was given an algorithm to implement and i did it in java. its some divide and conquer algorithm probably some comparison sort..heres the code i wrote...
import java.util.*;//so as to get the functions for using arrays public class main { public static void main(String[] args) { int m[]={10,2,3,4,5,6,7,8,9,1}; int result[]=new int[200];
[Code] ....
the program compiles without errors. but while running i get the following errors:
java.lang.ArrayIndexOutOfBoundsException: 10 at main.abc(main.java:28) at main.main(main.java:8) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)
I've seen examples that don't use a separate Runnable Implementation, but Instead Just make a subclass of Thread and override the Thread's runO method. That way,you call the Thread's no--arg constructor when you make the new thread;
Thread t = new Thread(); 1/no Runnable"
Any simple code that demonstrates the same. I haven't fully understood what is said in the text above. I have a hunch that the last line is wrong and it should be Thread t = new <Whatever class extends Thread class and over rides its run method>()
So we need to inform all active users of the website that "Website will be down after so and so time for maintenance". This is how I see the implementation.
User can be in any part of the application. So any time user request comes to server, it goes through the controllers. I can write a method (and call from each controller) that checks if message needs to be displayed. Put that into application context and display it. Along with that I will also have a flag that keeps track that if the message has already been displayed or not (to the user). If message has been displayed, no need to call that method again.
