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Multi-CH-Constructor

A multi-threaded multi-criteria contraction hierarchy graph creator. The general approach follows this paper. But a few improvements have been made to ensure that less shortcuts are generated. Less shortcuts lead to faster contraction time and higher speed-up of Dijkstra runs.

Build

To Build Multi-CH-Constructor first clone it and change into its directory:

git clone --recursive https://github.com/lesstat/multi-ch-constructor
cd multi-ch-constructor

Initialize submodules

git submodule update --init --recursive

Then create a build directory for cmake and run cmake and make.

cmake -Bbuild -D GRAPH_DIM=4 # only 'cmake -Bbuild' for default graph-dim
cmake --build build

Usage

The main executable of Multi-CH-Constructor is multi-ch. It has the following CLI options:

$ ./build/multi-ch -h
-h [ --help ] Prints help message
loading options:
-t [ --text ] arg Load graph from text file
-m [ --multi ] arg Load graph from multiple files
contraction options:
-p [ --percent ] arg (=98) How far the graph should be contracted
--stats Print statistics while contracting
--threads arg Maximal number of threads used
saving:
-w [ --write ] arg File to save graph to

It needs exactly one parameter of the loading category to load a graph. The text format is described in detail here. The Dimension of the graph must match the DIMENSION constant in the graph.hpp file. The application must be recompiled to contract graphs of other dimensions.

The -p option specifies how much of the graph will be contracted. This option can and should be given as decimal value aka -p 99.85.

The --stats options prints per thread per round information of the contraction.

With the --threads option the number of threads is specified. If left out the number of threads is determined by std::thread::hardware_concurrency()

-w specifies where to save the graph. The format is the same as the text format.

Shortcut Reducing Improvements

  • Duplicate shortcuts (source target and cost vector) are delete after every contraction round.

  • Augmented LP:

    The original paper proposes the following LP for finding a configuration the certifies the need for a shortcut. When checking path p~, for all paths p found form s to t which are not p~ introduce a constraint:

    alpha^T * (c(p) - c(p~)) <= 0

    This does not work when alpha^T * c(p) == alpha^T * c(p~). Therefore the following LP is used

    max delta
alpha^T * (c(p) - c(p~)) + delta <= 0

  • More than one path with minimal cost:

    When delta = 0 after the LP runs and more than one path has the same cost as the shortcut a heuristic search is done to find if one of the paths has no node that is contracted in this route inside. If one such path is found, it certifies that no shortcut is needed.

About

Creates contraction hierarchy graphs for multi metric graphs

Resources

Readme
GPL-3.0 license
Activity

Stars

7 stars

Watchers

1 watching

Forks

4 forks
Report repository

Releases

Packages

Contributors

Languages

, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

Skip to content
BranchesTags
Repository files navigation
Multi-CH-Constructor
A multi-threaded multi-criteria contraction hierarchy graph
creator. The general approach follows this
paper. But a
few improvements have been made to ensure that less shortcuts are
generated. Less shortcuts lead to faster contraction time and higher
speed-up of Dijkstra runs.
Build
To Build Multi-CH-Constructor first clone it and change into its directory:
git clone --recursive https://github.com/lesstat/multi-ch-constructor
cd multi-ch-constructor
Initialize submodules
git submodule update --init --recursive
Then create a build directory for cmake and run cmake and make.
cmake -Bbuild -D GRAPH_DIM=4 # only 'cmake -Bbuild' for default graph-dim
cmake --build build
Usage
The main executable of Multi-CH-Constructor is multi-ch. It has the following CLI options:
$ ./build/multi-ch -h
-h [ --help ] Prints help message
loading options:
-t [ --text ] arg Load graph from text file
-m [ --multi ] arg Load graph from multiple files
contraction options:
-p [ --percent ] arg (=98) How far the graph should be contracted
--stats Print statistics while contracting
--threads arg Maximal number of threads used
saving:
-w [ --write ] arg File to save graph to
It needs exactly one parameter of the loading category to load a
graph. The text format is described in detail
here. The
Dimension of the graph must match the DIMENSION constant in the
graph.hpp file. The application must be recompiled to contract graphs
of other dimensions.
The -p option specifies how much of the graph will be
contracted. This option can and should be given as decimal value aka
-p 99.85.
The --stats options prints per thread per round information of the contraction.
With the --threads option the number of threads is specified. If
left out the number of threads is determined by
std::thread::hardware_concurrency()
-w specifies where to save the graph. The format is the same as
the text format.
Shortcut Reducing Improvements
  • Duplicate shortcuts (source target and cost vector) are delete after
every contraction round.
  • Augmented LP:
    The original paper proposes the following LP for finding a
configuration the certifies the need for a shortcut.
When checking path p~, for all paths p found form s to t which are not
p~ introduce a constraint:
    alpha^T * (c(p) - c(p~)) <= 0

    This does not work when alpha^T * c(p) == alpha^T * c(p~). Therefore
the following LP is used
    max delta
alpha^T * (c(p) - c(p~)) + delta <= 0

  • More than one path with minimal cost:
    When delta = 0 after the LP runs and more than one path has the
same cost as the shortcut a heuristic search is done to find if one
of the paths has no node that is contracted in this route
inside. If one such path is found, it certifies that no shortcut is needed.
About
Creates contraction hierarchy graphs for multi metric graphs
Resources
Readme
GPL-3.0 license
Activity
Stars
7 stars
Watchers
1 watching
Forks
4 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Multi-CH-Constructor
A multi-threaded multi-criteria contraction hierarchy graph
creator. The general approach follows this
paper. But a
few improvements have been made to ensure that less shortcuts are
generated. Less shortcuts lead to faster contraction time and higher
speed-up of Dijkstra runs.
Build
To Build Multi-CH-Constructor first clone it and change into its directory:
git clone --recursive https://github.com/lesstat/multi-ch-constructor
cd multi-ch-constructor
Initialize submodules
git submodule update --init --recursive
Then create a build directory for cmake and run cmake and make.
cmake -Bbuild -D GRAPH_DIM=4 # only 'cmake -Bbuild' for default graph-dim
cmake --build build
Usage
The main executable of Multi-CH-Constructor is multi-ch. It has the following CLI options:
$ ./build/multi-ch -h
-h [ --help ] Prints help message
loading options:
-t [ --text ] arg Load graph from text file
-m [ --multi ] arg Load graph from multiple files
contraction options:
-p [ --percent ] arg (=98) How far the graph should be contracted
--stats Print statistics while contracting
--threads arg Maximal number of threads used
saving:
-w [ --write ] arg File to save graph to
It needs exactly one parameter of the loading category to load a
graph. The text format is described in detail
here. The
Dimension of the graph must match the DIMENSION constant in the
graph.hpp file. The application must be recompiled to contract graphs
of other dimensions.
The -p option specifies how much of the graph will be
contracted. This option can and should be given as decimal value aka
-p 99.85.
The --stats options prints per thread per round information of the contraction.
With the --threads option the number of threads is specified. If
left out the number of threads is determined by
std::thread::hardware_concurrency()
-w specifies where to save the graph. The format is the same as
the text format.
Shortcut Reducing Improvements
  • Duplicate shortcuts (source target and cost vector) are delete after
every contraction round.
  • Augmented LP:
    The original paper proposes the following LP for finding a
configuration the certifies the need for a shortcut.
When checking path p~, for all paths p found form s to t which are not
p~ introduce a constraint:
    alpha^T * (c(p) - c(p~)) <= 0

    This does not work when alpha^T * c(p) == alpha^T * c(p~). Therefore
the following LP is used
    max delta
alpha^T * (c(p) - c(p~)) + delta <= 0

  • More than one path with minimal cost:
    When delta = 0 after the LP runs and more than one path has the
same cost as the shortcut a heuristic search is done to find if one
of the paths has no node that is contracted in this route
inside. If one such path is found, it certifies that no shortcut is needed.
About
Creates contraction hierarchy graphs for multi metric graphs
Resources
Readme
GPL-3.0 license
Activity
Stars
7 stars
Watchers
1 watching
Forks
4 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Multi-CH-Constructor
A multi-threaded multi-criteria contraction hierarchy graph
creator. The general approach follows this
paper. But a
few improvements have been made to ensure that less shortcuts are
generated. Less shortcuts lead to faster contraction time and higher
speed-up of Dijkstra runs.
Build
To Build Multi-CH-Constructor first clone it and change into its directory:
git clone --recursive https://github.com/lesstat/multi-ch-constructor
cd multi-ch-constructor
Initialize submodules
git submodule update --init --recursive
Then create a build directory for cmake and run cmake and make.
cmake -Bbuild -D GRAPH_DIM=4 # only 'cmake -Bbuild' for default graph-dim
cmake --build build
Usage
The main executable of Multi-CH-Constructor is multi-ch. It has the following CLI options:
$ ./build/multi-ch -h
-h [ --help ] Prints help message
loading options:
-t [ --text ] arg Load graph from text file
-m [ --multi ] arg Load graph from multiple files
contraction options:
-p [ --percent ] arg (=98) How far the graph should be contracted
--stats Print statistics while contracting
--threads arg Maximal number of threads used
saving:
-w [ --write ] arg File to save graph to
It needs exactly one parameter of the loading category to load a
graph. The text format is described in detail
here. The
Dimension of the graph must match the DIMENSION constant in the
graph.hpp file. The application must be recompiled to contract graphs
of other dimensions.
The -p option specifies how much of the graph will be
contracted. This option can and should be given as decimal value aka
-p 99.85.
The --stats options prints per thread per round information of the contraction.
With the --threads option the number of threads is specified. If
left out the number of threads is determined by
std::thread::hardware_concurrency()
-w specifies where to save the graph. The format is the same as
the text format.
Shortcut Reducing Improvements
  • Duplicate shortcuts (source target and cost vector) are delete after
every contraction round.
  • Augmented LP:
    The original paper proposes the following LP for finding a
configuration the certifies the need for a shortcut.
When checking path p~, for all paths p found form s to t which are not
p~ introduce a constraint:
    alpha^T * (c(p) - c(p~)) <= 0

    This does not work when alpha^T * c(p) == alpha^T * c(p~). Therefore
the following LP is used
    max delta
alpha^T * (c(p) - c(p~)) + delta <= 0

  • More than one path with minimal cost:
    When delta = 0 after the LP runs and more than one path has the
same cost as the shortcut a heuristic search is done to find if one
of the paths has no node that is contracted in this route
inside. If one such path is found, it certifies that no shortcut is needed.
About
Creates contraction hierarchy graphs for multi metric graphs
Resources
Readme
GPL-3.0 license
Activity
Stars
7 stars
Watchers
1 watching
Forks
4 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
BranchesTags
Repository files navigation
Multi-CH-Constructor
A multi-threaded multi-criteria contraction hierarchy graph
creator. The general approach follows this
paper. But a
few improvements have been made to ensure that less shortcuts are
generated. Less shortcuts lead to faster contraction time and higher
speed-up of Dijkstra runs.
Build
To Build Multi-CH-Constructor first clone it and change into its directory:
git clone --recursive https://github.com/lesstat/multi-ch-constructor
cd multi-ch-constructor
Initialize submodules
git submodule update --init --recursive
Then create a build directory for cmake and run cmake and make.
cmake -Bbuild -D GRAPH_DIM=4 # only 'cmake -Bbuild' for default graph-dim
cmake --build build
Usage
The main executable of Multi-CH-Constructor is multi-ch. It has the following CLI options:
$ ./build/multi-ch -h
-h [ --help ] Prints help message
loading options:
-t [ --text ] arg Load graph from text file
-m [ --multi ] arg Load graph from multiple files
contraction options:
-p [ --percent ] arg (=98) How far the graph should be contracted
--stats Print statistics while contracting
--threads arg Maximal number of threads used
saving:
-w [ --write ] arg File to save graph to
It needs exactly one parameter of the loading category to load a
graph. The text format is described in detail
here. The
Dimension of the graph must match the DIMENSION constant in the
graph.hpp file. The application must be recompiled to contract graphs
of other dimensions.
The -p option specifies how much of the graph will be
contracted. This option can and should be given as decimal value aka
-p 99.85.
The --stats options prints per thread per round information of the contraction.
With the --threads option the number of threads is specified. If
left out the number of threads is determined by
std::thread::hardware_concurrency()
-w specifies where to save the graph. The format is the same as
the text format.
Shortcut Reducing Improvements
  • Duplicate shortcuts (source target and cost vector) are delete after
every contraction round.
  • Augmented LP:
    The original paper proposes the following LP for finding a
configuration the certifies the need for a shortcut.
When checking path p~, for all paths p found form s to t which are not
p~ introduce a constraint:
    alpha^T * (c(p) - c(p~)) <= 0

    This does not work when alpha^T * c(p) == alpha^T * c(p~). Therefore
the following LP is used
    max delta
alpha^T * (c(p) - c(p~)) + delta <= 0

  • More than one path with minimal cost:
    When delta = 0 after the LP runs and more than one path has the
same cost as the shortcut a heuristic search is done to find if one
of the paths has no node that is contracted in this route
inside. If one such path is found, it certifies that no shortcut is needed.
About
Creates contraction hierarchy graphs for multi metric graphs
Resources
Readme
GPL-3.0 license
Activity
Stars
7 stars
Watchers
1 watching
Forks
4 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Multi-CH-Constructor
A multi-threaded multi-criteria contraction hierarchy graph
creator. The general approach follows this
paper. But a
few improvements have been made to ensure that less shortcuts are
generated. Less shortcuts lead to faster contraction time and higher
speed-up of Dijkstra runs.
Build
To Build Multi-CH-Constructor first clone it and change into its directory:
git clone --recursive https://github.com/lesstat/multi-ch-constructor
cd multi-ch-constructor
Initialize submodules
git submodule update --init --recursive
Then create a build directory for cmake and run cmake and make.
cmake -Bbuild -D GRAPH_DIM=4 # only 'cmake -Bbuild' for default graph-dim
cmake --build build
Usage
The main executable of Multi-CH-Constructor is multi-ch. It has the following CLI options:
$ ./build/multi-ch -h
-h [ --help ] Prints help message
loading options:
-t [ --text ] arg Load graph from text file
-m [ --multi ] arg Load graph from multiple files
contraction options:
-p [ --percent ] arg (=98) How far the graph should be contracted
--stats Print statistics while contracting
--threads arg Maximal number of threads used
saving:
-w [ --write ] arg File to save graph to
It needs exactly one parameter of the loading category to load a
graph. The text format is described in detail
here. The
Dimension of the graph must match the DIMENSION constant in the
graph.hpp file. The application must be recompiled to contract graphs
of other dimensions.
The -p option specifies how much of the graph will be
contracted. This option can and should be given as decimal value aka
-p 99.85.
The --stats options prints per thread per round information of the contraction.
With the --threads option the number of threads is specified. If
left out the number of threads is determined by
std::thread::hardware_concurrency()
-w specifies where to save the graph. The format is the same as
the text format.
Shortcut Reducing Improvements
  • Duplicate shortcuts (source target and cost vector) are delete after
every contraction round.
  • Augmented LP:
    The original paper proposes the following LP for finding a
configuration the certifies the need for a shortcut.
When checking path p~, for all paths p found form s to t which are not
p~ introduce a constraint:
    alpha^T * (c(p) - c(p~)) <= 0

    This does not work when alpha^T * c(p) == alpha^T * c(p~). Therefore
the following LP is used
    max delta
alpha^T * (c(p) - c(p~)) + delta <= 0

  • More than one path with minimal cost:
    When delta = 0 after the LP runs and more than one path has the
same cost as the shortcut a heuristic search is done to find if one
of the paths has no node that is contracted in this route
inside. If one such path is found, it certifies that no shortcut is needed.
About
Creates contraction hierarchy graphs for multi metric graphs
Resources
Readme
GPL-3.0 license
Activity
Stars
7 stars
Watchers
1 watching
Forks
4 forks
Report repository
Releases
Packages
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
BranchesTags
Repository files navigation
Multi-CH-Constructor
A multi-threaded multi-criteria contraction hierarchy graph
creator. The general approach follows this
paper. But a
few improvements have been made to ensure that less shortcuts are
generated. Less shortcuts lead to faster contraction time and higher
speed-up of Dijkstra runs.
Build
To Build Multi-CH-Constructor first clone it and change into its directory:
git clone --recursive https://github.com/lesstat/multi-ch-constructor
cd multi-ch-constructor
Initialize submodules
git submodule update --init --recursive
Then create a build directory for cmake and run cmake and make.
cmake -Bbuild -D GRAPH_DIM=4 # only 'cmake -Bbuild' for default graph-dim
cmake --build build
Usage
The main executable of Multi-CH-Constructor is multi-ch. It has the following CLI options:
$ ./build/multi-ch -h
-h [ --help ] Prints help message
loading options:
-t [ --text ] arg Load graph from text file
-m [ --multi ] arg Load graph from multiple files
contraction options:
-p [ --percent ] arg (=98) How far the graph should be contracted
--stats Print statistics while contracting
--threads arg Maximal number of threads used
saving:
-w [ --write ] arg File to save graph to
It needs exactly one parameter of the loading category to load a
graph. The text format is described in detail
here. The
Dimension of the graph must match the DIMENSION constant in the
graph.hpp file. The application must be recompiled to contract graphs
of other dimensions.
The -p option specifies how much of the graph will be
contracted. This option can and should be given as decimal value aka
-p 99.85.
The --stats options prints per thread per round information of the contraction.
With the --threads option the number of threads is specified. If
left out the number of threads is determined by
std::thread::hardware_concurrency()
-w specifies where to save the graph. The format is the same as
the text format.
Shortcut Reducing Improvements
  • Duplicate shortcuts (source target and cost vector) are delete after
every contraction round.
  • Augmented LP:
    The original paper proposes the following LP for finding a
configuration the certifies the need for a shortcut.
When checking path p~, for all paths p found form s to t which are not
p~ introduce a constraint:
    alpha^T * (c(p) - c(p~)) <= 0

    This does not work when alpha^T * c(p) == alpha^T * c(p~). Therefore
the following LP is used
    max delta
alpha^T * (c(p) - c(p~)) + delta <= 0

  • More than one path with minimal cost:
    When delta = 0 after the LP runs and more than one path has the
same cost as the shortcut a heuristic search is done to find if one
of the paths has no node that is contracted in this route
inside. If one such path is found, it certifies that no shortcut is needed.
About
Creates contraction hierarchy graphs for multi metric graphs
Resources
Readme
GPL-3.0 license
Activity
Stars
7 stars
Watchers
1 watching
Forks
4 forks
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
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Multi-CH-Constructor
A multi-threaded multi-criteria contraction hierarchy graph
creator. The general approach follows this
paper. But a
few improvements have been made to ensure that less shortcuts are
generated. Less shortcuts lead to faster contraction time and higher
speed-up of Dijkstra runs.
Build
To Build Multi-CH-Constructor first clone it and change into its directory:
git clone --recursive https://github.com/lesstat/multi-ch-constructor
cd multi-ch-constructor
Initialize submodules
git submodule update --init --recursive
Then create a build directory for cmake and run cmake and make.
cmake -Bbuild -D GRAPH_DIM=4 # only 'cmake -Bbuild' for default graph-dim
cmake --build build
Usage
The main executable of Multi-CH-Constructor is multi-ch. It has the following CLI options:
$ ./build/multi-ch -h
-h [ --help ] Prints help message
loading options:
-t [ --text ] arg Load graph from text file
-m [ --multi ] arg Load graph from multiple files
contraction options:
-p [ --percent ] arg (=98) How far the graph should be contracted
--stats Print statistics while contracting
--threads arg Maximal number of threads used
saving:
-w [ --write ] arg File to save graph to
It needs exactly one parameter of the loading category to load a
graph. The text format is described in detail
here. The
Dimension of the graph must match the DIMENSION constant in the
graph.hpp file. The application must be recompiled to contract graphs
of other dimensions.
The -p option specifies how much of the graph will be
contracted. This option can and should be given as decimal value aka
-p 99.85.
The --stats options prints per thread per round information of the contraction.
With the --threads option the number of threads is specified. If
left out the number of threads is determined by
std::thread::hardware_concurrency()
-w specifies where to save the graph. The format is the same as
the text format.
Shortcut Reducing Improvements
  • Duplicate shortcuts (source target and cost vector) are delete after
every contraction round.
  • Augmented LP:
    The original paper proposes the following LP for finding a
configuration the certifies the need for a shortcut.
When checking path p~, for all paths p found form s to t which are not
p~ introduce a constraint:
    alpha^T * (c(p) - c(p~)) <= 0

    This does not work when alpha^T * c(p) == alpha^T * c(p~). Therefore
the following LP is used
    max delta
alpha^T * (c(p) - c(p~)) + delta <= 0

  • More than one path with minimal cost:
    When delta = 0 after the LP runs and more than one path has the
same cost as the shortcut a heuristic search is done to find if one
of the paths has no node that is contracted in this route
inside. If one such path is found, it certifies that no shortcut is needed.
About
Creates contraction hierarchy graphs for multi metric graphs
Resources
Readme
GPL-3.0 license
Activity
Stars
7 stars
Watchers
1 watching
Forks
4 forks
Report repository
Releases
Packages
Contributors
Languages