External polyphase merge sort - poor performanceRacing Java Arrays.sort with NON recursive Merge Sort...
GPLv2 - licensing for commercial use
How do I express some one as a black person?
Good allowance savings plan?
Latest web browser compatible with Windows 98
Rejected in 4th interview round citing insufficient years of experience
How do I deal with a powergamer in a game full of beginners in a school club?
Why does Deadpool say "You're welcome, Canada," after shooting Ryan Reynolds in the end credits?
In the late 1940’s to early 1950’s what technology was available that could melt a LOT of ice?
Set and print content of environment variable in cmd.exe subshell?
If the Captain's screens are out, does he switch seats with the co-pilot?
Who is eating data? Xargs?
Space in array system equations
Low budget alien movie about the Earth being cooked
Should I take out a loan for a friend to invest on my behalf?
What Happens when Passenger Refuses to Fly Boeing 737 Max?
Aliens englobed the Solar System: will we notice?
PTIJ: How can I halachically kill a vampire?
How to clip a background including nodes according to an arbitrary shape?
Built-In Shelves/Bookcases - IKEA vs Built
Is there an elementary proof that there are infinitely many primes that are *not* completely split in an abelian extension?
Tricky AM-GM inequality
How to create a hard link to an inode (ext4)?
Grey hair or white hair
How can The Temple of Elementary Evil reliably protect itself against kinetic bombardment?
External polyphase merge sort - poor performance
Racing Java Arrays.sort with NON recursive Merge Sort implementationConcurrent task processing queueEfficient Multithreaded File Processessing in JavaFile-based fixed-record merge sortExternal bottom up merge sort too slowParallel integer tree sort algorithm in JavaMemory/performance of merge sort codeParsing shorts from binary file and finding the closest and furthest pointsNode comparison using priority queue for Dijkstra's Shortest Path AlgorithmBottom-up singly linked list merge sort in C++
$begingroup$
I have implemented external polyphase merge sort which is useful to sort large files that do not fit into main memory. My implementation uses Priority queue as an internal data structure used to extract the smallest element when needed. For example:
int min_file;
FileRecord fr = queue.poll();
buff_writer.write(fr.getValue());
min_file = fr.getFileIndex(); //used to read from file from where min was taken
The algorithm (see link below) works as expected but it is very slow. The first - distribution phase works just fine without any performance issues. The problem must be somewhere in the second - merge phase. I have already removed/fixed some minor performance issues but the major issue is obviously still present.
More info about the algorithm itself can be found here and my implementation is available here (readme file and sample input file attached as well).
Thank you very much for the code review and suggestions.
java mergesort
asked 6 mins ago
henrichhenrich
1
New contributor
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I have implemented external polyphase merge sort which is useful to sort large files that do not fit into main memory. My implementation uses Priority queue as an internal data structure used to extract the smallest element when needed. For example:
int min_file;
FileRecord fr = queue.poll();
buff_writer.write(fr.getValue());
min_file = fr.getFileIndex(); //used to read from file from where min was taken
The algorithm (see link below) works as expected but it is very slow. The first - distribution phase works just fine without any performance issues. The problem must be somewhere in the second - merge phase. I have already removed/fixed some minor performance issues but the major issue is obviously still present.
More info about the algorithm itself can be found here and my implementation is available here (readme file and sample input file attached as well).
Thank you very much for the code review and suggestions.
java mergesort
asked 6 mins ago
henrichhenrich
1
New contributor
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I have implemented external polyphase merge sort which is useful to sort large files that do not fit into main memory. My implementation uses Priority queue as an internal data structure used to extract the smallest element when needed. For example:
int min_file;
FileRecord fr = queue.poll();
buff_writer.write(fr.getValue());
min_file = fr.getFileIndex(); //used to read from file from where min was taken
The algorithm (see link below) works as expected but it is very slow. The first - distribution phase works just fine without any performance issues. The problem must be somewhere in the second - merge phase. I have already removed/fixed some minor performance issues but the major issue is obviously still present.
More info about the algorithm itself can be found here and my implementation is available here (readme file and sample input file attached as well).
Thank you very much for the code review and suggestions.
java mergesort
asked 6 mins ago
henrichhenrich
1
New contributor
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I have implemented external polyphase merge sort which is useful to sort large files that do not fit into main memory. My implementation uses Priority queue as an internal data structure used to extract the smallest element when needed. For example:
int min_file;
FileRecord fr = queue.poll();
buff_writer.write(fr.getValue());
min_file = fr.getFileIndex(); //used to read from file from where min was taken
The algorithm (see link below) works as expected but it is very slow. The first - distribution phase works just fine without any performance issues. The problem must be somewhere in the second - merge phase. I have already removed/fixed some minor performance issues but the major issue is obviously still present.
More info about the algorithm itself can be found here and my implementation is available here (readme file and sample input file attached as well).
Thank you very much for the code review and suggestions.
java mergesort
java mergesort
asked 6 mins ago
henrichhenrich
1
New contributor
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 6 mins ago
henrichhenrich
1
New contributor
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 6 mins ago
henrichhenrich
1
New contributor
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 6 mins ago
henrichhenrich
1
asked 6 mins ago
henrichhenrich
1
1
New contributor
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
henrich is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
0
active
oldest
votes
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["\$", "\$"]]);
});
});
}, "mathjax-editing");
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "196"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
henrich is a new contributor. Be nice, and check out our Code of Conduct.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f215295%2fexternal-polyphase-merge-sort-poor-performance%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
0
active
oldest
votes
0
active
oldest
votes
active
oldest
votes
active
oldest
votes
henrich is a new contributor. Be nice, and check out our Code of Conduct.
henrich is a new contributor. Be nice, and check out our Code of Conduct.
henrich is a new contributor. Be nice, and check out our Code of Conduct.
henrich is a new contributor. Be nice, and check out our Code of Conduct.
Thanks for contributing an answer to Code Review Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f215295%2fexternal-polyphase-merge-sort-poor-performance%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
