I am working on a client server system, and am running into issues where multiple clients are executing an action at the same time. We are able to solve this by locking on the critical section of code, which ensures that the first client will complete the action before the second client enters the code block. My question is this: our se...
I have a rectangular planar grid, with each cell assigned some integer weight. I am looking for an algorithm to identify clusters of 3 to 6 adjacent cells with higher-than-average weight. These blobs should have approximately circular shape. For my case the average weight of the cells not containing a cluster is around 6, and that for c...
Can we combine multiple installations of Microsoft SQL Server 2005 or 2008 to act as a single database cluster? ...
I wonder whether there's a way to program a resource DLL for Windows Clusters in Delphi. I want to write a program that observes cluster state changes. Judging from the MSDN API reference, all relevant functions are located in the ClusAPI.h and ResAPI.h headers, but unfortunately it seems as if they haven't been ported yet and HeaderCon...
We (will) have the following architecture: Base.war will be a self-contained spring-hibernate application All applications will run under Glassfish, and may be clustered E1.war will sit on top of Base.war, extending it's functionality There could be further extensions (E2.war, E3.war, ) sitting on top of Base.war Either wars could star...
Hello, I am looking for a solution that allows me to deploy multiple load balanced Grails instances that have shared cache (EhCache Server ?) and sessions, is this possible ? I can't find any documentation on this (connecting to a common EhCache server or using Distributed EhCache, and sharing sessions (using EhCache too ?))... I'm lo...
Hi all I need to develop applications doing linear algebra + eigenvalue + linear equation solutions over a cluster of pcs ( I have a lot of machines available ). I discovered Scalapack libraries but they seem to me developed long time ago. Do you know if these are other libs available that I should learn doing math & linear algebra in ...
I would like to create some sort of a distributed setup for running a ton of small/simple REST web queries in a production environment. For each 5-10 related queries which are executed from a node, I will generate a very small amount of derived data, which will need to be stored in a standard relational database (such as PostgreSQL). Wh...
This is a question about k-means clustering algorithm. I have the following points and clustering of data S1. Can anyone tell me how to calculate the total error associated with this clustering? I know it's not a strictly programming question, but I need it for my algorithm. I think the answer should be 4/3 but I have no idea how to calc...
I am trying to group points of geospatial data based on density and relative distance. Is there a way that this can be done in SQL Server 2008 using the spatial features or would it be better to translate the data into graph data and use a graph clustering algorithm? ...
Hello, We have an .NET client app working against SQL Server 2005 (clustered), do I need to do something special in the client app to make it cluster aware? Thanks. ...
Hi All I am setting up a set of computers where to run math programs on top of MPI. Do you know whether exist some library doing PCA - Principal Component Analysis using MPI so to use all the resources of the networked pcs? I will have a look at Scalapack, but do you know other libraries? My language is C++ on linux but if there is a go...
Anyone aware of F/OSS library for clustering algorithms? Specifically interested in Hierarchical Clustering. Surely there are some libs available, not requiring writing up from scratch. p.s I know about NMath, it is $ ware ...
I have an application in a .ear: a .war archive and a .jar with EJBs. There are two clusters of servers. I want to deploy my .war on one cluster and the .jar to another, so that both of them can be individually deployed and to allow proper load balancing. Currently I'm getting the following error: Error resolving ejb-ref 'over.9.thous...
I have a set of datapoints each of which belongs to a certain cluster (group). I need to draw a polygon around each of these clusters. Does anyone knows how to do it? It doesn't matter if I use or not use the actual datapoints for drawing the polygon. I just need them to be wrapped in a polygon. ...
How can one generate say 1000 random points with a distribution like that of towns and cities in e.g. Ohio ? I'm afraid I can't define "distributed like cities" precisely; uniformly distributed centres + small Gaussian clouds are easy but ad hoc. Added: There must be a family of 2d distributions with a clustering parameter that can be va...
Hi, I have this code: cursor.execute( ''' SELECT id,DISTINCT tag FROM userurltag ''') tags = cursor.fetchall () T = [3,5,7,2,1,2,2,2,5,6,3,3,1,7,4] I have 7 groups names 1,...,7 . Each row in "tags" list corresponds to a row in "T" list.the values of "T" say that for example the first row in "tags" list belongs t...
We have a brand new webapp written that runs on Tomcat. So far, only one client is using it through the day. They run about 180 unique logins a day. Not really a lot IMO. Now, we managed to sell it to a brand new client who likes and wants to roll it out to 50,000 clients. How many of them will login at the same time - no idea. But I nee...
I want to simulate the behavior of 'erl -sname example -hidden' but dynamically. How can I drop a node out of visibility in a cluster? See the comments by @mwt at @Yasir Arsanukaev for additional clarification of what I'm trying to do. ...
How can I display a number in the marker on a google map? I want to do server side clustering and I need to display how many points the cluster represents. ...