I am continuing on in trying to build up the basics of matrix algebra from scratch.
I have created an object class called Matrix
import java.util.ArrayList;
public class Matrix {
public int NumRows;
public int NumColumns;
// This array contains the entries of our matrix.
ArrayList<Double> entry = new ArrayList<Double>();
[Code] ......
Bottom line: a matrix has a number of rows and a number of columns, and for each pair of row and column, we have a number in our matrix. The DisplayMatrix method prints my matrix to the screen, and the GetEntry method returns a particular value. This all works fine and dandy as far as I can tell.
A fundamental operation done to matrices to obtain a special matrix called the RREF is the process of switching 2 rows. Here is a method I have written that switches two rows of a matrix, and outputs the result as a new matrix. Note that I want the original matrix to be unchanged.
// Switch two rows
public static Matrix SwapRows(Matrix A, int r1, int r2){
if(r1<1 || r1>A.NumRows || r2<1 || r2>A.NumRows)
PRINTLN("illegally switching rows");
Matrix C = A;
double dummy[] = new double[A.NumColumns];
[Code] ....
How I call this, inside a public static void main(String[] args), is as follows:
// Declares that A is a 2 by 2 matrix.
Matrix A = new Matrix(2,2);
// We now add values in. The top left entry of A is 4, the top right entry of A is 1, the bottom left entry of A is 2, and the bottom right entry of A is 6.
double pony[]= new double[4];
pony[0]=4;
pony[1]=1;
pony[2]=2;
pony[3]=6;
A.AddEntries(pony);
// We can display the matrix in the output, and it looks exactly as expected!
A.DisplayMatrix();
// I am now going to create a new matrix called B. It is going to be obtained by flipping the first and second rows of A.
//Note that I want A is stay as I initialized it.
//I dont want A to have it's 2 rows switched. I want B to the matrix obtained by switching two rows of A.
Matrix B=SwapRows(A,1,2);
B.DisplayMatrix();
// Displaying B gives me the desired result. However, if I now display A again, it is the same as B.
A.DisplayMatrix();
Why is my matrix A being modified? Of course, I am more than capable of providing more details/comments if requested. I suspect that this is a super silly mistake.
I have a 5x5 array of which I read from an external file and I am supposed to print out the original matrix and then add up each row and column, proceeding to store them into the sixth positions in my matrix. After that I print out the new matrix.
I am confused as to how to isolate rows and print them out. I know how to add the entire matrix up but isolation is my issue.
Here is what I have including how to read the matrix and the sum of the whole thing
import java.io.*; import java.util.*; public class prog470cAddingRandC { public static void main (String [] args) { //read the file Scanner inFile=null;
I wrote this code which print a black image depends on the number of rows and columns you give it
public class BlackImg { private Mycolor[][] colorArr; //Mycolor is a class i wrote that represents colors. // no need for showing the class here. // so i created here an array of type Mycolor, for example: // { {(255,255,255), {(127,127,0)} }
[Code] .....
my problem is that my output comes good except the last line ,
Output: (0,0,0) (0,0,0) (0,0,0) (0,0,0) (0,0,0) (0,0,0) (0,0,0) (0,0,0) (0,0,0) (0,0,0) (0,0,0) (0,0,0) BlackImg@1db9742 //what is this line , why does it showing up ?
I need to write a class,that will give me output like this:
* *** **** *** *
I have to use for loop,i know that i have to use nested for loops, for rows and columns. I just cant figure it out the thing with spaces,and how to turn it to count back.
I am making rows and columns in the form of a multiplication table, listed below is my code:
package assignments; public class MultTable { public static void main (String [] args) { int row, column, x, y; for(row = 0; row < 8; row++)
[Code] .....
If you see my sample run you can see that I have the multiplication table down but, I haven't completed it. I have to make the bottom left half of the whole table blank somehow. For example, I have to make it halfway through the middle of the table the bottom left half full of white space...
5 6 7 8 9 12 14 16 18 21 24 27 32 36 90
hm, it's supposed to be the other way around horizontally.
How to sort data from a .csv file. The file has a column that contains duplicate groups, and a column that has duplicate employee id's. I need to take the data and sort it into rows. The employee's id will be in the first column, then the groups the employees belong in will occupy the following columns. The groups and employees are dynamic.
groups| empId ----------------- Group A| a1234 | Group A| e3456 | Group A| w3452 | Group A| d3456 | Group A| j7689 | [Code] ....
I want to format the .csv as follows:
-------------------------- empId | group 1 | group 2 | -------------------------- a1234 | group A | group B | --------------------------- w3452 | group A | group B | ---------------------------
I am trying to write a code for multidimensional array, allocate memory for variables and access the value of the arrays. I want them to be shown as rows and columns. but my code only shows one column and no rows. here is my code:
public static void main(String[] args) { int[ ][ ] aryNumbers = new int[2][2]; aryNumbers [0][0] = 1; aryNumbers [0][1] = 2; aryNumbers [1][0] = 3; aryNumbers [1][1] = 4; int rows = 2; int columns = 2;
I have an application that displays a GUI and this GUI displays a table with several columns and rows. I have a class that extends DefaultTableModel. I wrote the code that displays the GUI. When the database table changes, how would I updated the GUI dynamically? Do you have any sample code that does that?
i'd been using Opencsv to upload all this data into my Db(Postgres) using EclipseLink with batch inserting, it wont take more than 5 secs to load 200k+ data cause all the columns are of type string so theres no format require, the problem comes when i need to give a special format to the data that is in this table (date, Integer, etc).
Right now how it works:
- Ill go row by row (when its required) verifying the format of the data and convert it with something like this Ex: Date date = Fechas.strToDate(data, Pattern) and fill the new Object with this info
what i'm planing to do
- With the function of EclipseLink OPERATOR im gonna use that to change all the rows of a column that requires a NUMBER format with OPERATOR('ToNumber',column1,'9999999999')
i cant do the same for Date cause ill get an error if the data doesn't have a Date like pattern
how to handle this Date formatting(from a query, or directly in java).
We have triangle made of blocks. The topmost row has 1 block, the next row down has 2 blocks, the next row has 3 blocks, and so on. Compute recursively (no loops or multiplication) the total number of blocks in such a triangle with the given number of rows.
I am working through a text and I am supposed to complete the following tasks.
Your ReadFiles.java class requires the following methods:
Method: check to see if the file exists
Method: find number of rows in csv file
Method: Converts the csv file to a mutli-dimensional array
Method: PrintArray
Method: Return array using a get method
Create a file DataAnalyzer.java. This file will be used to call the methods in ReadFiles.java. Be sure to demonstrate that all of your methods work through DataAnalyzer.java.
The problem is that it does not really provide any information on how to go about reading a file into an array. I am stuck at the third task of converting the file to an array and I have tried several ways to do this unsuccessfully. I thought that I would at least try to get things to print out (line 87) to see if I could get that to work, but all that prints in null over and over again.
Java Code:
public class DataAnalyzer { public static void main (String[] args) { ReadFiles aReadFiles = new ReadFiles(); aReadFiles.fileCheck(); aReadFiles.findRows(); aReadFiles.convertFile();
I have to organize the rows from the lower to the higher number, the problem is, what I have only organizes the first 3 rows even If I insert 3,4,5...or 10 rows.
for (int i = arg[0].length - 1; i >= 0; i--) { for (int j = 0; j < i ; j++) { for (int k = 0; k < i ; k++) { if (arg[k][j] > arg[k][j + 1]) { int temp = arg[k][j];
I am very new to Java Swing. I have to create a TreeTable in Java Swing with a Parent Row having say 6 columns and its all child row having just 4 columns. like shown below
The problem is, the values are completely different than they are saved in MATLAB, and probably I need to shift the values after transforming them into byte arrays.My Java code which reads values of floating numbers from a MATLAB bin file as follows:
import java.io.*; import java.io.File; import javax.imageio.ImageIO; import java.nio.ByteBuffer; // may be useful? public class floatingNumberMatrixReader {
Design a class named LinearEquation for a 2 X 2 system of linear equations:
ax + by = e cx + dy = f Where x = ed − bf/ad − bc y = af − ec/ad − bc
The class contains:
- Private data fields a, b, c, d, e, and f. - A constructor with the arguments for a, b, c, d, e, and f. - Six get methods for a, b, c, d, e, and f. - A method named isSolvable() that returns true if ad−bc is not 0. - Methods getX() and getY() that return the solution for the equation.
[code].....
how to display the information I need to display. Also I am not so sure that I wrote the code properly, I do not get any errors when I compile it.
I've been trying to program a software for minimizing (sum of products and products of sum) a boolean algebra using Quine mccluskey method... I've created the GUI and I got stuck in the process... I need a code for minimizing a 10 variable function ....
Write a program that prompts the user to enter an integer m and find the smallest integer n such that m * n is a perfect square. (Hint: Store all smallest factors of m into an array list. n is the product of the factors that appear an odd number of times in the array list. For example, consider m = 90, store the factors 2, 3, 3, 5 in an array list. 2 and 5 appear an odd number of time in the array list. So, n is 10.)
so far my program is just like this.
import java.lang.Math; import java.util.Scanner; public class PerfectSquare { public static void main(String[] args) { Scanner m = new Scanner(System.in); int Fint;
[Code] .....
how do i make the program find the smallest integer n?
I have a JScrollPane with two coulmns. In the first column I have an image pane JTable, and in the second a list with names of sections. This second column I try to divide in two columns, one (the second column) to display the names of the sections (each row contains one name), and in the other column (the third) I want to show some values for every section in the row respectively. But, instead of displaying the desired values in the third column, I get the same names of the sections as in the second column. Here is a part of the code I have:
private Vector<Section>daten = new Vector<Section>(0); //These are the values for the first column in the Jscroll private String[] header = {"Section","calcGYR"}; // These are the values for the second and third column (in this case the header for the both columns public TrafficObserveModel(Vector<Section> daten) { setData(daten);
[code]....
But I don't know how to modify the methods in order to render the desired integer values in the third column.
public static void displayOutputs (int[][] anArray) { System.out.println("Here is your 2Dim array:"); for (int i = 0; i < anArray.length; i++) { System.out.println(Arrays.deepToString(anArray)); } }
This is my code and I get this as a result when I input 10,20,30,...,90 into array[0][0], array[0][1], ..., array[2][2] (3rows, 3columns array)
[[10, 20, 30], [40, 50, 60], [70, 80, 90]]
[[10, 20, 30], [40, 50, 60], [70, 80, 90]]
[[10, 20, 30], [40, 50, 60], [70, 80, 90]]
While I expect to get only
[10, 20, 30]
[40, 50, 60]
[70, 80, 90]
I get no errors at least when I have the same # of rows and # of columns. However, when I have more columns than rows, a compiler stops running when it runs columnSum method.Here's an error message.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2 at lab10.Array2DMethods.columnSum(Arrays2DDemo.java:70) at lab10.Arrays2DDemo.main(Arrays2DDemo.java:111) Java Result: 1
And here's my code
public static void columnSum (int[][] anArray) { int sum =0; for (int col=0; col < anArray.length; col++) { sum=0; for (int r = 0; r < anArray[col].length; r++ ){ sum += anArray[r][col]; } System.out.println("Sum of column " + col + " = " + sum); } }
why my code doesn't work when I have more columns.
How can I find the overall averages of the columns in this array?when i run my code it gives me an output that looks like this (showing me wrong averages): 0 1 2 3 overall grade
