Using TinkerPop3 as the interface to a DSE graph. Is there any easy way to detect cycles in a graph or rather not visit an already visited vertex.
Specifically in my case, There is a "GROUP" vertex and there can be a group of groups. I will like to list all "USERS" in a group of groups.
Have you worked with the Gremlin steps SimplePath or ClyclicPath ? http://tinkerpop.apache.org/docs/3.3.1/reference/#cyclicpath-step
SimplePath sounds like it will do what you are interested in doing.
Related
I read a couple of posts on position nodes in force layout but didn't find an answer to what I was looking for.
I have an object with nodes and links.
I' trying to create a graph which would show all the nodes top to bottom.
I was looking at the example code from here:
https://github.com/danielstern/force-graph-example
Here's a screenshot of the result:
I'm trying to find a way to position each node so the nodes without parents would be on the top and the ones connecting to them would be under them and so forth.
Here's an image to illustrate it:
Right now, all the nodes are scattered randomly.
I wanted to if I need to actually calculate the position of each node in a vertical view or is there a smarter/built-in way to achieve it.
I looked at this example which looked promising:
How to organise node positions in D3 Force layout
But in my case I don't have a way to differentiate between nodes levels so I don't think the yPostion would help.
I was also looking at thes post:
d3.js - How can I expand force directed graph horizontally?
According to #Lars Kotthoff:
"The point of the force layout is to automatically lay out a graph like this so that you don't have to specify the positions of the nodes yourself".
Since my graph is not really a tree, I don't think the tree view would match.
What would be my best approach to position the nodes?
Or perhaps there's a better library to achieve what I need?
I found this package:
d3-dag
It basically supports what I need:
"Often data sets are hierarchical, but are not in a tree structure..."
Here's an exmaple:
exmaple
I am trying to find Landing Spaces as well as Intermediate Landings for Ramps using Revit API, for a few of my models. So far I have tried to find Start and Endpoints of the ramp using location parameters as mentioned in the following blog space (How to find start/end of ramp in revit, perhaps with sketches?) , but it seems that this parameter is unavailable in the models I am trying to use.
I tried to explore any other way using Revit API functionalities but with no visible success so far. Also, I am new to Revit Api's and as such have a limited understanding of what features are available in API.
Can someone help me Identify Ramp Landings or Ramp endpoints?
Ramp Location
Ramp Property Pallete
I see three possible approaches:
Location
Sketch
Geometry
Using the Location property, casting it LocationCurve and grabbing the endpoints from that as suggested in the other discussion you link to would be the optimal solution.
Another approach mentioned in that thread is to use the sketch defining the ramp to determine its start and end points. Getting hold of the sketch elements is not completely trivial, but absolutely doable, as explained in The Building Coder discussions on
Stable Reference Relationships
Retrieving and Snooping Dependent Elements
If all else fails, the final alternative would be to grab and analyse the ramp geometry to deduce the required information from that.
I've spent hours searching for an answer to this, but in most cases either the
question is about plots/charts (rather than graphs as in "control flow graph"),
or the answer "just use graphviz" is a valid answer.
However I have some constraints and requirements that make "just use graphviz" a
non-answer.
The full graph is large enough that it's not possible to generate a graphviz
for all of it.
Nodes and edges will be dynamically added and removed.
Nodes have lots of information that will be hidden by default and will be
expanded on request (imagine every node as a table with expandable rows/cols)
I want to be able to show only a subset of the graph on request, e.g. for
features like "only show reachable part of the graph from this node" or "show
all simple paths from this node to this node".
Basically I want to be able to start drawing nodes and edges on a 2D plane, and
add new nodes and edges dynamically. It's fine if nodes/edges move around as new
stuff is added. While I don't yet have hard requirements for this, it'd be good
if it looked "nice" -- for example if a node has lots of incoming edges (this is
a directed graph) ideally it'd be in a central place on the plane with all other
nodes around it etc.
Anything that gets me going would be helpful. Thanks.
(I don't know what label to add to this, adding "graph-theory" because I don't know what else to add)
I have coordinates, which are assigned a corresponding geohash in my database. Now I want to retrieve all of the coordinates within two bounding coordinates (top right and top left corner). How can I do that properly?
I tried getting the geohash that fits both of those bounding coordinates, but this solution does not work when they are in completely different regions of the world (so they are not sharing anything in common).
Is there a better way to do that?
Thanks for your help
Unfortunately, this isn't something you can do out-of-the-box with datastore / App engine. (There are no built in spatial queries.)
For early prototyping, etc., you can do it the hard way - retrieve all the rows, and discard the ones not meeting your query in code. Obviously, probably not viable with real production data.
See related question Query for Entities Nearby with Geopt for some possible production solutions.
I have a MetroManila.osm file and i parse it so it can read roads only using this command: --keep = --keep-nodes=highway --keep-ways=. Is this the right command for filtering only the roads? What i want after parsing is to create a node where there's intersections or curves, or is it possible with just using the whole nodes in MetroManila.osm? Can i create an edge using it and how do i do it? Currently, i'm really lost on what to do since i'm fairly new on android studio and in osmdroid.
This hasn't really anything to do with Android or osmdroid.
For learning how to create a routing graph from an OSM file see the related answer at help.openstreetmap.org. Quoting from it:
parse all ways; throw away those that are not roads, and for the others, remember the node IDs they consist of, by incrementing a "link counter" for each node referenced.
parse all ways a second time; a way will normally become one edge, but if any nodes apart from the first and the last have a link counter greater than one, then split the way into two edges at that point. Nodes with a link counter of one and which are neither first nor last can be thrown away unless you need to compute the length of the edge.
(if you need geometry for your graph nodes) parse the nodes section of the XML now, recording coordinates for all nodes that you have retained.
Also take a look at routing in the OSM wiki to get some general hints and existing tools and libraries.
Regarding osmdroid: If you don't rely on offline routing then take a look at osmbonuspack, it supports online routing.
If you don't want to reinvent the wheel then just use one of the existing offline routing tools mentioned in the OSM wiki.