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https://github.com/chenlily/closest-pair
https://github.com/chenlily/closest-pair
Last synced: 1 day ago
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- Host: GitHub
- URL: https://github.com/chenlily/closest-pair
- Owner: chenlily
- Created: 2015-05-27T17:24:34.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2015-06-17T17:42:23.000Z (over 9 years ago)
- Last Synced: 2024-08-04T04:07:03.602Z (3 months ago)
- Language: C++
- Size: 152 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
- awesome-mesos - Closest-pairs in 2D with divide-and-conquer
README
# closest-pair
A framework for [Apache Mesos](http://mesos.apache.org/) that given a file with a list of 2D points, calculates the closest distance between any two points in that set. Implements a divide-and-conquer algorithm which determines the result in
O(nlogn) time instead of brute-force O(n^2).
Based on [Rendler](https://github.com/mesosphere/RENDLER) implementation.
Closest-Pair consists of two main components:
* `ClosestPairExecutor` extends `mesos.Executor`
* `ClosestPairScheduler` extends `mesos.Scheduler`
## Quick Start with Vagrant
### Requirements
- [VirtualBox](http://www.virtualbox.org/) 4.1.18+
- [Vagrant](http://www.vagrantup.com/) 1.3+
- [git](http://git-scm.com/downloads) (command line tool)
### Start the `mesos-demo` VM
```bash
$ wget http://downloads.mesosphere.io/demo/mesos.box -O /tmp/mesos.box
$ vagrant box add --name mesos-demo /tmp/mesos.box
$ git clone https://github.com/chenlily/closest-pair
$ vagrant up
```
### Execution:
```bash
$ vagrant ssh
vagrant@mesos:~ $ cd hostfiles
# Update install dependencies
vagrant@mesos:cpp $ sudo apt-get update
vagrant@mesos:cpp $ sudo apt-get install libcurl4-openssl-dev libboost-regex1.55-dev \
libprotobuf-dev libgoogle-glog-dev protobuf-compiler
# Build
vagrant@mesos:cpp $ make all
# Start the scheduler with the test file and the mesos master ip
vagrant@mesos:cpp $ ./closest-pair-scheduler testfile 127.0.1.1:5050
# to stop...
```
### Shutting down the `mesos-demo` VM
```bash
# Exit out of the VM
vagrant@mesos:hostfiles $ exit
# Stop the VM
$ vagrant halt
# To delete all traces of the vagrant machine
$ vagrant destroy
```
### Test File Format
Points can be either integers or floating point
```
x1 y1
x2 y2
x3 y3
```
## Closest-Pair Architecture
### Closest-Pair Scheduler
### Data Structures
A point is represented by a struct x and y coordinates.
```c++
struct Point(
double x,y;
)
```
A split on an array into its left and right components is represented by a SplitInfo. It contains the left and right indices of its subarray, a parent ID, the minimum distances on its left and right halves, and also whether the split is a left or right child to its parent. If the split is the original/root array, the direction is set as NONE.
```c++
struct SplitInfo (
int left, right parent;
double lMinDist, rMinDist;
// enum Direction {LEFT, RIGHT, NONE};
Direction dir;
)
```
* `pointvector` vector of Points containing the original array of Points
* `splitQueue` list of vectors to be split in half
* `parentMap` maps parentIDs to their splitInfo, also acts as a list of splitInfo whose minDistances still need to be calculated
#### Scheduler Behavior
The scheduler accepts a text file as command-line parameter to create a vector of points to calculate the minimum distance.
* Reads in the file and initializes a point vector
* Split each vector into two halves until it is 2 or fewer elements. On each split, create a SplitInfo object representing the split and insert it into the parentMap
* Until parentMap is empty, launch a combiner task to calculate the minDistance on splitInfo objects that minimum distances calculated on the left and right sides. Update splitInfo's parent through parentMap.
* Print the final minDistance through stdout
### Combiner Executor
- Interprets incoming tasks' `task.data` field as an array of points, the subarray's parentID, minDistance on its left and right halves, and also whether the subarray is a left or right child to its parent
- Calculates the minDistance in that subarray of points
- Returns the subarray's minDistance, parentID, and relation to its parent to the scheduler in the data field of a TaskStatus