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POPlotting/Working with 1million nodes
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  1. POPlotting/Working with 1million nodes
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    copied!<p>I am busy with an exercise to plot nodes on a pane. My first goal is to work with 1million nodes and then ramp it up to 15million. </p> <p>I have a custom Object Graph and I can add edges and nodes to this object. Each node object has an ellipse that I can call and plot and same with the edge objects. At the moment I have a function that generates a random position for the nodes.</p> <p>I am using a scroll pane at the moment to enable panning around the pane and to view all the nodes.</p> <p>What I thought was a good idea was to use a hashmap</p> <pre><code>Map&lt;String, ArrayList&lt;Node&gt;&gt; mapX = new HashMap&lt;String, ArrayList&lt;Node&gt;&gt;(); Map&lt;String, ArrayList&lt;Node&gt;&gt; mapY = new HashMap&lt;String, ArrayList&lt;Node&gt;&gt;(); </code></pre> <p>I use the following code to add nodes to the hashmap:</p> <pre><code>int tempXFloor = (int)Math.floor(tempX); ArrayList&lt;Node&gt; tempList = mapX.get(tempXFloor+""); if(tempList == null){ tempList = new ArrayList&lt;&gt;(); } tempList.add(node); mapX.put(tempXFloor+"",tempList); </code></pre> <p>Then while I am panning I get the current position, floor it and check if an entry exist in the map. if an entry exist, I add all the nodes in the ArrayList to nodesOnScreen. nodesOnScreen is an ArrayList type, and I will add the nodes to that list while I am panning and likewise the nodes that are off the screen are removed from the nodesOnScreen variable.</p> <p>I only plot the nodes that is in the ArrayList nodesOnScreen.</p> <p>I would appreciate some guidance in this matter, and how to handle such big data structures. Am I going in the right direction or am I missing an obvious "trick" to do it.</p>
 

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