Java Objects And Classes - System Of Linear Equation

Mar 15, 2015

The question states: 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.

Write a test program that prompts the user to enter a, b, c, d, e, and f and displays the result. If ad − bc is 0, report that "The equation has no solution."

I believe that my program is correct because I am able to compile it and get no errors, however I have no clue how to display the information for x and y or display this equation has no solution if ad-bc=0.

Java Code:

import java.util.Scanner;
public class Exer911 {
public static void main(String[] args){
// Create a scanner system to hold the numbers for each variable
Scanner input = new Scanner(System.in);
// Prompt the user to enter a number for each of the variables

[Code] ....

How to get the information to display ....

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Solver For System Of Linear Equation In Java For Large Matrices (finite Element Program)

Jan 16, 2014

I develop a finite element code at java. I am looking for efficiency solver and fast for large, sparse , symmetric and positive define matrices .

i used in jblas but i encounter in problem when the matrix has high condition number(ill condition number) and i get error for singular matrix while in mathematica i succeed to solve that system without problems...

Any good solver and fast solver package in java can i use for solving that system?

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So i was assigned to write a program that would print the answer to the system of two linear equation. the form of ax+by=c and dx+ey=f..I wrote this program, but it is incorrect since I tried it out on my terminal and I keep getting incorrect values.

import java.util.Scanner;
public class Quest4 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);

[code]....

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Mar 16, 2014

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/**
* Employee Class containing all non-primitive data types.
*
*/

class Employee{
private String name;
private String phone;
private Integer age;
private Float salary;

[Code] ....

Any Technique that will decide which one of the fields (Integer, Address, DOB, String, Float) are user defined type. (An outsider class should used that will identify the Java classes and the user-defined classes.)

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Oct 13, 2014

I'm finding common elements in a collection of arrays. This is my code so far.

import java.util.ArrayList;
import java.util.List;
public class CommonElements //< T extends Comparable<T> >
{
Comparable[] comparable;
Comparable[] tempArr;
Comparable[] tempArr1;
Comparable[] newArray = new Comparable[tempArr.length];
int comparisonCount;
 
 [code]....

I'm using this method to sort through my array. The method accepts a collection of arrays (of varying length and of any type) as input, the algorithm input should be no greater than n(k-1). I know I can solve it using a quadratic algorithm, but it won't meet the requirement of the assignment. I did have an idea of storing all my algorithm in one giant array. After storing as one giant array I was going to sort it. After sorting I was going to compare each array side by side and see if they are the same. Here is note my teacher provided.

Note About Testing You will need to develop several sets of test collections for testing your algorithm. The grading rubric mentions covering the case where all the test collections have the same length, as well as covering the case where the test collections are of different lengths. You will also need to think about what constitutes the worst case scenario for this algorithm, since only that scenario will make your analysis of total comparisons performed a meaningful one. You can use the formulas in the grading rubric to tell you how many comparisons you should expect in the quadratic and linear cases. For example, if you have 5 total collections (1 query collection and 4 test collections), each of which contains 10 elements, the total number of comparisons performed in the worst case should be: (k - 1)N2, which for k = 10 and N = 10 is: (5 - 1)102, or 400 comparisons. For the linear algorithm, you should only have N*(k - 1), which is 10*(5 - 1), or 40 comparisons.

Here is Q/A that my teacher provided:

1. Are the elements in the collections already sorted?The input collections may or may not be sorted. Don’t assume that they are sorted.

2. Can I sort the elements in the collections? Am I supposed to sort the elements in thecollections?Yes, you can sort the elements in the collections. It is not required that you do so, however..

3. If I sort the collections, should I count the element comparisons that are performed by the sorting algorithm?No. The only element comparisons you should count are the ones that are directly used to find the common elements. Ignore comparisons performed by any sorting algorithms you use.

4. How do I extract an individual collection from the Object[] collections argument of the findCommonElements method?You will need to typecast each collection as type Comparable[]. For example:Comparable[] currentCollection = (Comparable[])collections[i];

5. Why are we using a one-dimensional Object array instead of a two-dimensional array of type Comparable (e.g., Comparable[][])?In Java, arrays are treated as objects, so only a variable of type Object[] can contain arrays. A variable of type Comparable[] can only contain Comparable elements, not arrays. A variable of type Comparable[][] also can only store Comparable elements. Although it is possible to organize the elements such that all the elements at indexes [1][i], for example, are considered to comprise a collection, this is not the same as having an array that contains other arrays. The additional bookkeeping is required to keep a 2D array organized is more complex than simply performing the typecast described above.

6. Can I use other data structures besides arrays; e.g., HashMaps?No. Although it is easier from a programming perspective to use higher order data structures like HashMaps to find common elements, using these structures simply hides the details. If you were to examine the implementations of those structures, you would probably find that they use relatively inefficient algorithms such as sequential searches to find elements. Additionally, if you use library components, you have no way of counting the number of comparisons performed, since you don’t have access to the source code of those components.

7. Is this a trick question? I can’t think of any way to get below NlogN comparisons.It is not a trick question. It is possible to solve this problem using a number of comparisons proportional to (k – 1) * N.

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Java - Compute PI Using Equation

Oct 24, 2014

Part 1: USING A WHILE OR A DO-WHILE LOOP write a program to compute PI using the following equation:

PI = 3 + 4/(2*3*4) - 4/(4*5*6) + 4/(6*7*8) - 4/(8*9*10) + ...

Allow the user to specify the number of terms (5 terms are shown) to use in the computation. Each time around the loop only one extra term should be added to the estimate for PI.

Alter your solution from part one so that the user is allowed to specify the precision required between 1 and 8 digits (i.e. the number of digits which are correct; e.g. to 5 digits PI is 3.14159), rather than the number of terms. The condition on the loop should be altered so that it continues until the required precision is obtained. Note that you need only submit this second version of the program (assuming you have it working).

My output for part 1 is :

Enter number of wanted terms for value of PI
100
PI = 3.1666666666666665 Number of Term = 2
PI = 3.1333333333333333 Number of Term = 3
PI = 3.145238095238095 Number of Term = 4
PI = 3.1396825396825396 Number of Term = 5
PI = 3.1427128427128426 Number of Term = 6
PI = 3.1408813408813407 Number of Term = 7
PI = 3.142071817071817 Number of Term = 8
PI = 3.1412548236077646 Number of Term = 9
PI = 3.141839618929402 Number of Term = 10 ................ and so on

I know you have to compare value of current Pi to the previous one but I'm stuck.

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String[] user = {"admin"};
String[] passwords = {"firkanten"};
boolean check = false;
for (int i = 0; i < user.length; i++) {
if (userName.equals(user[i])) {
if (password.equals(passwords[i])) {
check = true;

Now, in another class I want a display box to appear on the screen and give the user three options: Click yes, no or cancel. I get this to run perfectly alone, this is not the hard part for me. I want the display box only to appear when the correct username and password is given, but I can't seem to figure out how to do this probably.

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Feb 14, 2015

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In steps, I have to:

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Now, to start, I have a class for the number generator, a class to store the array of 25 words, and a class for the game itself.

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Mar 15, 2015

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.

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import java.util.ArrayList;
import java.util.Scanner;
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public static void main(String[] args) {
ArrayList<Account> al = new ArrayList<Account>();
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[code]....

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[Code].....

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Java Code:

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[Code] ....

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[code]....

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