Solved

Java long division in finite field 2

Posted on 2011-09-14
8
359 Views
Last Modified: 2012-05-12
How do I do a long division in galois field 2 in java?
0
Comment
Question by:humansg
  • 4
  • 2
8 Comments
 
LVL 59

Expert Comment

by:Kevin Cross
ID: 36539976
humansg, before we get started, is this for a homework assignment? If so, do you know how to work out the long division manually as I can help you translate that to Java, thus helping you "learn" versus just spitting out an answer...
0
 

Author Comment

by:humansg
ID: 36543181
yes, it is part of an assignment which I need to call for part of euclid algorithm..
yes i know how to do the long division manually.
0
 
LVL 59

Expert Comment

by:Kevin Cross
ID: 36543269
Okay. Great. Please post what you have for the calculation as you understand it in your attempt in Java. If you are getting any compilation or run-time errors, then you should post details on those. For run-time errors, posting the full stack trace in a code snippet is very useful. If the issue is logical, i.e., everything compiles and runs but you are not getting the expected results, then ensure to post what you expect alongside what you are getting currently.

From there, we can guide you through correcting the code.
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 

Accepted Solution

by:
humansg earned 0 total points
ID: 36556907
public static int gf2LongDivideQ(int dividend, int divisor) {

        int dividendLength = getLengthOf(dividend);
        int divisorLength = getLengthOf(divisor);

        if (divisorLength > dividendLength) {
            return -1;
        }

        int tempDividend = 0;

        int quotient = 0;

        for (int i = 1; i <= dividendLength; i++) {
            int bitAtPositionI = getBit(dividend, i);

            tempDividend = (tempDividend << 1) + bitAtPositionI;

            if (getLengthOf(tempDividend) < divisorLength) { // cannot divide
                // append '0' to end of quotient
                quotient = (quotient << 1);
            } else {
                // perform xor operation
                tempDividend = tempDividend ^ divisor;

                // append '1' to end of quotient
                quotient = (quotient << 1) + 1;
            }
        }

        return quotient;
    }

    public static int getLengthOf(int input) {
        int length = 0;
        while (input != 0) {
            input = input >> 1;
            length++;
        }
        return length;
    }

    public static int getBit(int input, int index) {
        input = input >> (getLengthOf(input) - index); // shift out bits to the right by (length - index)
        input = input & 0x1; // get right most bit
        return input;
    }

Open in new window

0
 

Author Closing Comment

by:humansg
ID: 36585517
Coded out myself. Should be able to work..
0
 

Author Comment

by:humansg
ID: 36556915
accepting own solution..
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Introduction This article is the first of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article explains our test automation goals. Then rationale is given for the tools we use to a…
In this post we will learn how to connect and configure Android Device (Smartphone etc.) with Android Studio. After that we will run a simple Hello World Program.
Viewers learn about the third conditional statement “else if” and use it in an example program. Then additional information about conditional statements is provided, covering the topic thoroughly. Viewers learn about the third conditional statement …
This tutorial covers a step-by-step guide to install VisualVM launcher in eclipse.

910 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

21 Experts available now in Live!

Get 1:1 Help Now