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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Christopher,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>This is the wrong group to be asking this question. You want to be on the pgRouting Users or pgRouting develop group. Join details here: http://pgrouting.org/support.html<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>This question probably makes sense to ask on both pgRouting users and dev, since it is both a development change and a "Would user's like this and a support question?" So I've cc'd both.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Hope that helps,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>Regina<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> postgis-users-bounces@lists.osgeo.org [mailto:postgis-users-bounces@lists.osgeo.org] <b>On Behalf Of </b>Christoph Mayrhofer<br><b>Sent:</b> Monday, August 24, 2015 12:09 PM<br><b>To:</b> postgis-users@lists.osgeo.org<br><b>Subject:</b> [postgis-users] floyd-warhall all pairs shortest path<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><div><div><p class=MsoNormal style='margin-left:.5in'>Hi,<o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>I looked into all pairs shortest path routing algorithms to use for traffic simulations. <o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>I found that the Floyd–Warshall algorithm works well for my purpose. <o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>pgRouting has a function for this which produces a table with the shortest path distance between all source/destination pairs.<o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>In order to get the actual paths rather than only distances it suffices to make a minor adaption to the algorithm as described in the path reconstruction section in <a href="https://en.wikipedia.org/wiki/Floyd%E2%80%93Warshall_algorithm">https://en.wikipedia.org/wiki/Floyd%E2%80%93Warshall_algorithm</a><o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>It is basically supposed to output the first node of the shortest path between the source and destination in addition to the overall distance of that route. <o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>This information is sufficient to reconstruct all paths using the parent child relationship recursively.<o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>Does pgr_apspWarshall support this?<o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>Or can anyone point to the person that implemented pgr_apspWarshall?<o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>So far I use my own implementation outside of PostGIS, but I think whis functionality might be of interest for others too.<o:p></o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p></div><div><p class=MsoNormal style='margin-left:.5in'>best regards, Christoph Mayrhofer<o:p></o:p></p></div></div></div></body></html>