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  • Setting up a VPN connection to Amazon VPC - routing

    - by Keeno
    I am having some real issues setting up a VPN between out office and AWS VPC. The "tunnels" appear to be up, however I don't know if they are configured correctly. The device I am using is a Netgear VPN Firewall - FVS336GV2 If you see in the attached config downloaded from VPC (#3 Tunnel Interface Configuration), it gives me some "inside" addresses for the tunnel. When setting up the IPsec tunnels do I use the inside tunnel IP's (e.g. 169.254.254.2/30) or do I use my internal network subnet (10.1.1.0/24) I have tried both, when I tried the local network (10.1.1.x) the tracert stops at the router. When I tried with the "inside" ips, the tracert to the amazon VPC (10.0.0.x) goes out over the internet. this all leads me to the next question, for this router, how do I set up stage #4, the static next hop? What are these seemingly random "inside" addresses and where did amazon generate them from? 169.254.254.x seems odd? With a device like this, is the VPN behind the firewall? I have tweaked any IP addresses below so that they are not "real". I am fully aware, this is probably badly worded. Please if there is any further info/screenshots that will help, let me know. Amazon Web Services Virtual Private Cloud IPSec Tunnel #1 ================================================================================ #1: Internet Key Exchange Configuration Configure the IKE SA as follows - Authentication Method : Pre-Shared Key - Pre-Shared Key : --- - Authentication Algorithm : sha1 - Encryption Algorithm : aes-128-cbc - Lifetime : 28800 seconds - Phase 1 Negotiation Mode : main - Perfect Forward Secrecy : Diffie-Hellman Group 2 #2: IPSec Configuration Configure the IPSec SA as follows: - Protocol : esp - Authentication Algorithm : hmac-sha1-96 - Encryption Algorithm : aes-128-cbc - Lifetime : 3600 seconds - Mode : tunnel - Perfect Forward Secrecy : Diffie-Hellman Group 2 IPSec Dead Peer Detection (DPD) will be enabled on the AWS Endpoint. We recommend configuring DPD on your endpoint as follows: - DPD Interval : 10 - DPD Retries : 3 IPSec ESP (Encapsulating Security Payload) inserts additional headers to transmit packets. These headers require additional space, which reduces the amount of space available to transmit application data. To limit the impact of this behavior, we recommend the following configuration on your Customer Gateway: - TCP MSS Adjustment : 1387 bytes - Clear Don't Fragment Bit : enabled - Fragmentation : Before encryption #3: Tunnel Interface Configuration Your Customer Gateway must be configured with a tunnel interface that is associated with the IPSec tunnel. All traffic transmitted to the tunnel interface is encrypted and transmitted to the Virtual Private Gateway. The Customer Gateway and Virtual Private Gateway each have two addresses that relate to this IPSec tunnel. Each contains an outside address, upon which encrypted traffic is exchanged. Each also contain an inside address associated with the tunnel interface. The Customer Gateway outside IP address was provided when the Customer Gateway was created. Changing the IP address requires the creation of a new Customer Gateway. The Customer Gateway inside IP address should be configured on your tunnel interface. Outside IP Addresses: - Customer Gateway : 217.33.22.33 - Virtual Private Gateway : 87.222.33.42 Inside IP Addresses - Customer Gateway : 169.254.254.2/30 - Virtual Private Gateway : 169.254.254.1/30 Configure your tunnel to fragment at the optimal size: - Tunnel interface MTU : 1436 bytes #4: Static Routing Configuration: To route traffic between your internal network and your VPC, you will need a static route added to your router. Static Route Configuration Options: - Next hop : 169.254.254.1 You should add static routes towards your internal network on the VGW. The VGW will then send traffic towards your internal network over the tunnels. IPSec Tunnel #2 ================================================================================ #1: Internet Key Exchange Configuration Configure the IKE SA as follows - Authentication Method : Pre-Shared Key - Pre-Shared Key : --- - Authentication Algorithm : sha1 - Encryption Algorithm : aes-128-cbc - Lifetime : 28800 seconds - Phase 1 Negotiation Mode : main - Perfect Forward Secrecy : Diffie-Hellman Group 2 #2: IPSec Configuration Configure the IPSec SA as follows: - Protocol : esp - Authentication Algorithm : hmac-sha1-96 - Encryption Algorithm : aes-128-cbc - Lifetime : 3600 seconds - Mode : tunnel - Perfect Forward Secrecy : Diffie-Hellman Group 2 IPSec Dead Peer Detection (DPD) will be enabled on the AWS Endpoint. We recommend configuring DPD on your endpoint as follows: - DPD Interval : 10 - DPD Retries : 3 IPSec ESP (Encapsulating Security Payload) inserts additional headers to transmit packets. These headers require additional space, which reduces the amount of space available to transmit application data. To limit the impact of this behavior, we recommend the following configuration on your Customer Gateway: - TCP MSS Adjustment : 1387 bytes - Clear Don't Fragment Bit : enabled - Fragmentation : Before encryption #3: Tunnel Interface Configuration Outside IP Addresses: - Customer Gateway : 217.33.22.33 - Virtual Private Gateway : 87.222.33.46 Inside IP Addresses - Customer Gateway : 169.254.254.6/30 - Virtual Private Gateway : 169.254.254.5/30 Configure your tunnel to fragment at the optimal size: - Tunnel interface MTU : 1436 bytes #4: Static Routing Configuration: Static Route Configuration Options: - Next hop : 169.254.254.5 You should add static routes towards your internal network on the VGW. The VGW will then send traffic towards your internal network over the tunnels. EDIT #1 After writing this post, I continued to fiddle and something started to work, just not very reliably. The local IPs to use when setting up the tunnels where indeed my network subnets. Which further confuses me over what these "inside" IP addresses are for. The problem is, results are not consistent what so ever. I can "sometimes" ping, I can "sometimes" RDP using the VPN. Sometimes, Tunnel 1 or Tunnel 2 can be up or down. When I came back into work today, Tunnel 1 was down, so I deleted it and re-created it from scratch. Now I cant ping anything, but Amazon AND the router are telling me tunnel 1/2 are fine. I guess the router/vpn hardware I have just isnt up to the job..... EDIT #2 Now Tunnel 1 is up, Tunnel 2 is down (I didn't change any settings) and I can ping/rdp again. EDIT #3 Screenshot of route table that the router has built up. Current state (tunnel 1 still up and going string, 2 is still down and wont re-connect)

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  • fluent nhibernate select n+1 problem

    - by Andrew Bullock
    I have a fairly deep object graph (5-6 nodes), and as I traverse portions of it NHProf is telling me I've got a "Select N+1" problem (which I do). The two solutions I'm aware of are Eager load children Break apart my object graph (and eager load) I don't really want to do either of these (although I may break the graph apart later as I forsee it growing) For now.... Is it possible to tell NHibernate (with fluentnhib) that whenever i try to access children, to load them all in one go, instead of selectn+1ing as i iterate over them? I'm also getting "unbounded results set"s, which is presumably the same problem (or rather, will be solved by the above solution if possible). Each child collection (throughout the graph) will only ever have about 20 members, but 20^5 is a lot, so i dont want to eager load everything when i get the root, but simply get all of a child collection whenever i go near it Edit: an afterthought.... what if i want to introduce paging when i want to render children? do i HAVE to break my object graph here, or is there some sneakyness i can employ to solve all these issues?

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  • Puppet's automatically generated certificates failing

    - by gparent
    I am running a default configuration of Puppet on Debian Squeeze 6.0.4. The server's FQDN is master.example.com. The client's FQDN is client.example.com. I am able to contact the puppet master and send a CSR. I sign it using puppetca -sa but the client will still not connect. Date of both machines is within 2 seconds of Tue Apr 3 20:59:00 UTC 2012 as I wrote this sentence. This is what appears in /var/log/syslog: Apr 3 17:03:52 localhost puppet-agent[18653]: Reopening log files Apr 3 17:03:52 localhost puppet-agent[18653]: Starting Puppet client version 2.6.2 Apr 3 17:03:53 localhost puppet-agent[18653]: Could not retrieve catalog from remote server: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed Apr 3 17:03:53 localhost puppet-agent[18653]: Using cached catalog Apr 3 17:03:53 localhost puppet-agent[18653]: Could not retrieve catalog; skipping run Here is some interesting output: OpenSSL client test: client:~# openssl s_client -host master.example.com -port 8140 -cert /var/lib/puppet/ssl/certs/client.example.com.pem -key /var/lib/puppet/ssl/private_keys/client.example.com.pem -CAfile /var/lib/puppet/ssl/certs/ca.pem CONNECTED(00000003) depth=1 /CN=Puppet CA: master.example.com verify return:1 depth=0 /CN=master.example.com verify error:num=7:certificate signature failure verify return:1 depth=0 /CN=master.example.com verify return:1 18509:error:1409441B:SSL routines:SSL3_READ_BYTES:tlsv1 alert decrypt error:s3_pkt.c:1102:SSL alert number 51 18509:error:140790E5:SSL routines:SSL23_WRITE:ssl handshake failure:s23_lib.c:188: client:~# master's certificate: root@master:/etc/puppet# openssl x509 -text -noout -in /etc/puppet/ssl/certs/master.example.com.pem Certificate: Data: Version: 3 (0x2) Serial Number: 2 (0x2) Signature Algorithm: sha1WithRSAEncryption Issuer: CN=Puppet CA: master.example.com Validity Not Before: Apr 2 20:01:28 2012 GMT Not After : Apr 2 20:01:28 2017 GMT Subject: CN=master.example.com Subject Public Key Info: Public Key Algorithm: rsaEncryption RSA Public Key: (1024 bit) Modulus (1024 bit): 00:a9:c1:f9:4c:cd:0f:68:84:7b:f4:93:16:20:44: 7a:2b:05:8e:57:31:05:8e:9c:c8:08:68:73:71:39: c1:86:6a:59:93:6e:53:aa:43:11:83:5b:2d:8c:7d: 54:05:65:c1:e1:0e:94:4a:f0:86:58:c3:3d:4f:f3: 7d:bd:8e:29:58:a6:36:f4:3e:b2:61:ec:53:b5:38: 8e:84:ac:5f:a3:e3:8c:39:bd:cf:4f:3c:ff:a9:65: 09:66:3c:ba:10:14:69:d5:07:57:06:28:02:37:be: 03:82:fb:90:8b:7d:b3:a5:33:7b:9b:3a:42:51:12: b3:ac:dd:d5:58:69:a9:8a:ed Exponent: 65537 (0x10001) X509v3 extensions: X509v3 Basic Constraints: critical CA:FALSE Netscape Comment: Puppet Ruby/OpenSSL Internal Certificate X509v3 Key Usage: critical Digital Signature, Key Encipherment X509v3 Subject Key Identifier: 8C:2F:14:84:B6:A1:B5:0C:11:52:36:AB:E5:3F:F2:B9:B3:25:F3:1C X509v3 Extended Key Usage: critical TLS Web Server Authentication, TLS Web Client Authentication Signature Algorithm: sha1WithRSAEncryption 7b:2c:4f:c2:76:38:ab:03:7f:c6:54:d9:78:1d:ab:6c:45:ab: 47:02:c7:fd:45:4e:ab:b5:b6:d9:a7:df:44:72:55:0c:a5:d0: 86:58:14:ae:5f:6f:ea:87:4d:78:e4:39:4d:20:7e:3d:6d:e9: e2:5e:d7:c9:3c:27:43:a4:29:44:85:a1:63:df:2f:55:a9:6a: 72:46:d8:fb:c7:cc:ca:43:e7:e1:2c:fe:55:2a:0d:17:76:d4: e5:49:8b:85:9f:fa:0e:f6:cc:e8:28:3e:8b:47:b0:e1:02:f0: 3d:73:3e:99:65:3b:91:32:c5:ce:e4:86:21:b2:e0:b4:15:b5: 22:63 root@master:/etc/puppet# CA's certificate: root@master:/etc/puppet# openssl x509 -text -noout -in /etc/puppet/ssl/certs/ca.pem Certificate: Data: Version: 3 (0x2) Serial Number: 1 (0x1) Signature Algorithm: sha1WithRSAEncryption Issuer: CN=Puppet CA: master.example.com Validity Not Before: Apr 2 20:01:05 2012 GMT Not After : Apr 2 20:01:05 2017 GMT Subject: CN=Puppet CA: master.example.com Subject Public Key Info: Public Key Algorithm: rsaEncryption RSA Public Key: (1024 bit) Modulus (1024 bit): 00:b5:2c:3e:26:a3:ae:43:b8:ed:1e:ef:4d:a1:1e: 82:77:78:c2:98:3f:e2:e0:05:57:f0:8d:80:09:36: 62:be:6c:1a:21:43:59:1d:e9:b9:4d:e0:9c:fa:09: aa:12:a1:82:58:fc:47:31:ed:ad:ad:73:01:26:97: ef:d2:d6:41:6b:85:3b:af:70:00:b9:63:e9:1b:c3: ce:57:6d:95:0e:a6:d2:64:bd:1f:2c:1f:5c:26:8e: 02:fd:d3:28:9e:e9:8f:bc:46:bb:dd:25:db:39:57: 81:ed:e5:c8:1f:3d:ca:39:cf:e7:f3:63:75:f6:15: 1f:d4:71:56:ed:84:50:fb:5d Exponent: 65537 (0x10001) X509v3 extensions: X509v3 Basic Constraints: critical CA:TRUE Netscape Comment: Puppet Ruby/OpenSSL Internal Certificate X509v3 Key Usage: critical Certificate Sign, CRL Sign X509v3 Subject Key Identifier: 8C:2F:14:84:B6:A1:B5:0C:11:52:36:AB:E5:3F:F2:B9:B3:25:F3:1C Signature Algorithm: sha1WithRSAEncryption 1d:cd:c6:65:32:42:a5:01:62:46:87:10:da:74:7e:8b:c8:c9: 86:32:9e:c2:2e:c1:fd:00:79:f0:ef:d8:73:dd:7e:1b:1a:3f: cc:64:da:a3:38:ad:49:4e:c8:4d:e3:09:ba:bc:66:f2:6f:63: 9a:48:19:2d:27:5b:1d:2a:69:bf:4f:f4:e0:67:5e:66:84:30: e5:85:f4:49:6e:d0:92:ae:66:77:50:cf:45:c0:29:b2:64:87: 12:09:d3:10:4d:91:b6:f3:63:c4:26:b3:fa:94:2b:96:18:1f: 9b:a9:53:74:de:9c:73:a4:3a:8d:bf:fa:9c:c0:42:9d:78:49: 4d:70 root@master:/etc/puppet# Client's certificate: client:~# openssl x509 -text -noout -in /var/lib/puppet/ssl/certs/client.example.com.pem Certificate: Data: Version: 3 (0x2) Serial Number: 3 (0x3) Signature Algorithm: sha1WithRSAEncryption Issuer: CN=Puppet CA: master.example.com Validity Not Before: Apr 2 20:01:36 2012 GMT Not After : Apr 2 20:01:36 2017 GMT Subject: CN=client.example.com Subject Public Key Info: Public Key Algorithm: rsaEncryption RSA Public Key: (1024 bit) Modulus (1024 bit): 00:ae:88:6d:9b:e3:b1:fc:47:07:d6:bf:ea:53:d1: 14:14:9b:35:e6:70:43:e0:58:35:76:ac:c5:9d:86: 02:fd:77:28:fc:93:34:65:9d:dd:0b:ea:21:14:4d: 8a:95:2e:28:c9:a5:8d:a2:2c:0e:1c:a0:4c:fa:03: e5:aa:d3:97:98:05:59:3c:82:a9:7c:0e:e9:df:fd: 48:81:dc:33:dc:88:e9:09:e4:19:d6:e4:7b:92:33: 31:73:e4:f2:9c:42:75:b2:e1:9f:d9:49:8c:a7:eb: fa:7d:cb:62:22:90:1c:37:3a:40:95:a7:a0:3b:ad: 8e:12:7c:6e:ad:04:94:ed:47 Exponent: 65537 (0x10001) X509v3 extensions: X509v3 Basic Constraints: critical CA:FALSE Netscape Comment: Puppet Ruby/OpenSSL Internal Certificate X509v3 Key Usage: critical Digital Signature, Key Encipherment X509v3 Subject Key Identifier: 8C:2F:14:84:B6:A1:B5:0C:11:52:36:AB:E5:3F:F2:B9:B3:25:F3:1C X509v3 Extended Key Usage: critical TLS Web Server Authentication, TLS Web Client Authentication Signature Algorithm: sha1WithRSAEncryption 33:1f:ec:3c:91:5a:eb:c6:03:5f:a1:58:60:c3:41:ed:1f:fe: cb:b2:40:11:63:4d:ba:18:8a:8b:62:ba:ab:61:f5:a0:6c:0e: 8a:20:56:7b:10:a1:f9:1d:51:49:af:70:3a:05:f9:27:4a:25: d4:e6:88:26:f7:26:e0:20:30:2a:20:1d:c4:d3:26:f1:99:cf: 47:2e:73:90:bd:9c:88:bf:67:9e:dd:7c:0e:3a:86:6b:0b:8d: 39:0f:db:66:c0:b6:20:c3:34:84:0e:d8:3b:fc:1c:a8:6c:6c: b1:19:76:65:e6:22:3c:bf:ff:1c:74:bb:62:a0:46:02:95:fa: 83:41 client:~#

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  • Plot Title/Annotation

    - by Kevin
    Hello, I want to add a title to my graph that gives a short description or name about the plot. For example, I have a table with a list of products and my graph shows how much those products cost. There should be a label/annotation superimposed on the graph that gives the name of the product.

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  • How can I return default at loop end in Scheme?

    - by Kufi Annan
    I'm trying to implement back-tracking search in Scheme. So far, I have the following: (define (backtrack n graph assignment) (cond (assignment-complete n assignment) (assignment) ) (define u (select-u graph assignment)) (define c 1) (define result 0) (let forLoop () (when (valid-choice graph assignment c) (hash-set! assignment u c) (set! result (backtrack n graph assignment)) (cond ((not (eq? result #f)) result)) (hash-remove! assignment u) ) (set! c (+ c 1)) (when (>= n c) (forLoop)) ) #f ) My functions assignment-complete and select-u pass unit tests. The argument assignment is a hash-table make with (make-hash), so it should be fine. I believe the problem I have is related to returning false at the end of the loop, if no recursive returns a non-false value (which should be a valid assignment).

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  • Transform/redraw view after pinch zoom on x-axis

    - by Jonathan
    My setup. UIScrollView (scrollView) - UIView (contentView) - UIView (subView) I have managed to do so I can zoom contentView only on the x-axis. The problem is that subView is containing a graph. When contentView is zoomed and transformed the graph gets unsharp and distorded since the scaling only effect the x-axis. What I need help with is to somehow redraw the contentView after I'm done with the zooming without distorting the graph. Is it possible to transform the contentView so that the graph stays sharp even if you only zoom in the x-axis or redraw the content in the zoomed/stretched view somehow? I have tried the solution in this thread link but haven't succeeded to get it running.

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  • After drawing circles on C# form how can i know on what circle i clicked?

    - by SorinA.
    I have to represent graphically an oriented graph like in the image below. i have a C# form, when i click with the mouse on it i have to draw a node. If i click somewhere on the form where is not already a node drawn it means i cliked with the intetion of drawing a node, if it is a node there i must select it and memorize it. On the next mouse click if i touch a place where there is not already a node drawn it means like before that i want to draw a new node, if it is a node where i clicked i need to draw the line from the first memorized node to the selected one and add road cost details. i know how to draw the circles that represent the nodes of the graph when i click on the form. i'm using the following code: namespace RepGraficaAUnuiGraf { public partial class Form1 : Form { Graphics graphDrawingArea; Bitmap bmpDrawingArea; Graphics graph; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { bmpDrawingArea = new Bitmap(Width, Height); graphDrawingArea = Graphics.FromImage(bmpDrawingArea); graph = Graphics.FromHwnd(this.Handle); } private void Form1_Click(object sender, EventArgs e) { DrawCentralCircle(((MouseEventArgs)e).X, ((MouseEventArgs)e).Y, 15); graph.DrawImage(bmpDrawingArea, 0, 0); } void DrawCentralCircle(int CenterX, int CenterY, int Radius) { int start = CenterX - Radius; int end = CenterY - Radius; int diam = Radius * 2; bmpDrawingArea = new Bitmap(Width, Height); graphDrawingArea = Graphics.FromImage(bmpDrawingArea); graphDrawingArea.DrawEllipse(new Pen(Color.Blue), start, end, diam, diam); graphDrawingArea.DrawString("1", new Font("Tahoma", 13), Brushes.Black, new PointF(CenterX - 8, CenterY - 10)); } } } My question is how can i find out if at the coordinates (x,y) on my form i drew a node and which one is it? I thought of representing the nodes as buttons, having a tag or something similar as the node number(which in drawing should be 1 for Santa Barbara, 2 for Barstow etc.)

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  • Ruby GraphViz Binary Tree Record

    - by Jason M
    I'm using the ruby-graphviz gem and I'm trying to draw binary trees. I'd like to use the record shape so that each node can have a left, middle, and right field and, thus, if there are two edges leaving a node, the left and right edges can be distinguished. I tried specifying the field by concatenating the field name like this: @node1.name + ":left" But that did not work. What is the correct way of specifying the field? require 'rubygems' require 'graphviz' @graph = GraphViz.new( :G, :type => :digraph ) @node1 = @graph.add_node("1", "shape" => "record", "label" => "<left>|<f1> 1|<right>" ) @node2 = @graph.add_node("2", "shape" => "record", "label" => "<left>|<f1> 2|<right>" ) @graph.add_edge(@node1.name + ":left", @node2) # generate a random filename filename = "/tmp/#{(0...8).map{65.+(rand(25)).chr}.join}.png" @graph.output( :png => filename ) exec "open #{filename}"

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  • Optimizing Python code with many attribute and dictionary lookups

    - by gotgenes
    I have written a program in Python which spends a large amount of time looking up attributes of objects and values from dictionary keys. I would like to know if there's any way I can optimize these lookup times, potentially with a C extension, to reduce the time of execution, or if I need to simply re-implement the program in a compiled language. The program implements some algorithms using a graph. It runs prohibitively slowly on our data sets, so I profiled the code with cProfile using a reduced data set that could actually complete. The vast majority of the time is being burned in one function, and specifically in two statements, generator expressions, within the function: The generator expression at line 202 is neighbors_in_selected_nodes = (neighbor for neighbor in node_neighbors if neighbor in selected_nodes) and the generator expression at line 204 is neighbor_z_scores = (interaction_graph.node[neighbor]['weight'] for neighbor in neighbors_in_selected_nodes) The source code for this function of context provided below. selected_nodes is a set of nodes in the interaction_graph, which is a NetworkX Graph instance. node_neighbors is an iterator from Graph.neighbors_iter(). Graph itself uses dictionaries for storing nodes and edges. Its Graph.node attribute is a dictionary which stores nodes and their attributes (e.g., 'weight') in dictionaries belonging to each node. Each of these lookups should be amortized constant time (i.e., O(1)), however, I am still paying a large penalty for the lookups. Is there some way which I can speed up these lookups (e.g., by writing parts of this as a C extension), or do I need to move the program to a compiled language? Below is the full source code for the function that provides the context; the vast majority of execution time is spent within this function. def calculate_node_z_prime( node, interaction_graph, selected_nodes ): """Calculates a z'-score for a given node. The z'-score is based on the z-scores (weights) of the neighbors of the given node, and proportional to the z-score (weight) of the given node. Specifically, we find the maximum z-score of all neighbors of the given node that are also members of the given set of selected nodes, multiply this z-score by the z-score of the given node, and return this value as the z'-score for the given node. If the given node has no neighbors in the interaction graph, the z'-score is defined as zero. Returns the z'-score as zero or a positive floating point value. :Parameters: - `node`: the node for which to compute the z-prime score - `interaction_graph`: graph containing the gene-gene or gene product-gene product interactions - `selected_nodes`: a `set` of nodes fitting some criterion of interest (e.g., annotated with a term of interest) """ node_neighbors = interaction_graph.neighbors_iter(node) neighbors_in_selected_nodes = (neighbor for neighbor in node_neighbors if neighbor in selected_nodes) neighbor_z_scores = (interaction_graph.node[neighbor]['weight'] for neighbor in neighbors_in_selected_nodes) try: max_z_score = max(neighbor_z_scores) # max() throws a ValueError if its argument has no elements; in this # case, we need to set the max_z_score to zero except ValueError, e: # Check to make certain max() raised this error if 'max()' in e.args[0]: max_z_score = 0 else: raise e z_prime = interaction_graph.node[node]['weight'] * max_z_score return z_prime Here are the top couple of calls according to cProfiler, sorted by time. ncalls tottime percall cumtime percall filename:lineno(function) 156067701 352.313 0.000 642.072 0.000 bpln_contextual.py:204(<genexpr>) 156067701 289.759 0.000 289.759 0.000 bpln_contextual.py:202(<genexpr>) 13963893 174.047 0.000 816.119 0.000 {max} 13963885 69.804 0.000 936.754 0.000 bpln_contextual.py:171(calculate_node_z_prime) 7116883 61.982 0.000 61.982 0.000 {method 'update' of 'set' objects}

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  • How do I oly show some nodes (edges) on graphviz and not others

    - by Pietro Speroni
    I have a very complex graph, and there is no way that I can show it all and understand it. I need to make simplified versions of it showing only some nodes and not others. I don't just want the other nodes to be invisible, but to really be absent (so that the graph is simplified). The solution would be to make a graph with only some layers. But is that possible? What other options are there? Thanks, Pietro

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  • CorePlot - Set y-Axis range to include all data points

    - by zdestiny
    I have implemented a CorePlot graph in my iOS application, however I am unable to dynamically size the y-Axis based on the data points in the set. Some datasets range from 10-50, while others would range from 400-500. In both cases, I would like to have y-origin (0) visible. I have tried using the scaletofitplots method: [graph.defaultPlotSpace scaleToFitPlots:[graph allPlots]]; but this has no effect on the graphs, they still show the default Y-Axis range of 0 to 1. The only way that I can change the y-Axis is to do it manually via this: graph.defaultPlotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(0.0f)) length:CPTDecimalFromFloat(500.0f)]; however this doesn't work well for graphs with smaller ranges (10-50), as you can imagine. Is there any method to retrieve the highest y-value from my dataset so that I can manually set the maximum y-Axis to that value? Or is there a better alternative?

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  • Google Visualization Annotated Time Line, removing data points.

    - by Vitaly Babiy
    I am trying to build a graph that will change resolution depending on how far you are zoomed in. Here is what it looks like when you are complete zoomed out. So this looks good so when I zoom in I get a higher resolution data and my graph looks like this: The problem is when I zoom out the higher resolution data does not get cleared out of the graph: The tables below the graphs are table display what is in the DataTable. This is what drawing code looks like. var g_graph = new google.visualization.AnnotatedTimeLine(document.getElementById('graph_div_json')); var table = new google.visualization.Table(document.getElementById('table_div_json')); function handleQueryResponse(response){ log("Drawing graph") var data = response.getDataTable() g_graph.draw(data, {allowRedraw:true, thickness:2, fill:50, scaleType:'maximized'}) table.draw(data, {allowRedraw:true}) } I am try to find a way for it to only displaying the data that is in the DataTable. I have tried removing the allowRedraw flag but then it breaks the zooming operation. Any help would be greatly appreciated. Thanks

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  • How to "check for overwide node(s)." in graphviz dot file

    - by Tomas Forsman
    I'm trying to generate a large graph using graphviz. I have a generated text file with nodes defined in the dot format. When I try to generate a PNG file from the file using dot -Tpng:cairo graph.txt graph.png I get the error message: Error: Edge length 136228 larger than maximum 65535 allowed. Check for overwide node(s). How do I actually "check for overwide node(s)" ?

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  • how use graphvis in C# application?

    - by ghasedak -
    i have a dot format file and i download graphvis for windows now how can i use graphvis to show a graph in my c# application? using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using VDS.RDF; using VDS.RDF.Parsing; using VDS.RDF.Query; using System.IO; using System.Windows; using System.Runtime.InteropServices; using VDS.RDF.Writing; using System.Diagnostics; namespace WindowsFormsApplication2 { public partial class first : Form { Graph g = new Graph(); string s1 = null; /**************************************DATA********************************************/ public first() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { Stream myStream = null; var parser = new Notation3Parser(); var graph = new Graph(); OpenFileDialog openFileDialog1 = new OpenFileDialog(); openFileDialog1.Filter = "RDF files (*.n3)|*.n3"; openFileDialog1.FilterIndex = 1; openFileDialog1.RestoreDirectory = true; openFileDialog1.Multiselect = false; if (openFileDialog1.ShowDialog() == DialogResult.OK) { try { if ((myStream = openFileDialog1.OpenFile()) != null) { using (myStream) { string s = openFileDialog1.FileName.ToString(); string w= Directory.GetCurrentDirectory().ToString(); string Fname = openFileDialog1.SafeFileName.ToString(); File.Copy(s,Path.Combine(w,Fname),true); // Insert code to read the stream here. Win32.AllocConsole(); s1 = Path.Combine(w, Fname); insertNodeButton.Visible = true; delBut.Visible = true; simi.Visible = true; showNodes showNodes1 = new showNodes(s1); g = showNodes1.returngraph(); Console.Read(); Win32.FreeConsole(); // g.SaveToFile("firstfile.n3"); this.Show(); } } } catch (Exception ex) { MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message); } } GraphVizWriter hi = new GraphVizWriter(); hi.Save(g, "c:\\ahmad.dot"); } private void button2_Click(object sender, EventArgs e) { string strCmdLine = Application.StartupPath + "\\Tools\\rdfEditor.exe"; //string strCmdLine = "DIR"; MessageBox.Show(strCmdLine); System.Diagnostics.Process process1; process1 = new System.Diagnostics.Process(); //Do not receive an event when the process exits. process1.EnableRaisingEvents = false; //The "/C" Tells Windows to Run The Command then Terminate System.Diagnostics.Process.Start(strCmdLine); process1.Close(); } private void Form1_Load(object sender, EventArgs e) { } private void insertNodeButton_Click(object sender, EventArgs e) { //Graph parentvalue = this.g; //String parentvalueadress = this.s1; addTriple a1 = new addTriple(); a1.G = g; a1.BringToFront(); a1.ShowDialog(); g = a1.G; g.SaveToFile("c:\\Hi.n3"); } this is my code i want to visul saly dot file format to show a graph with graphvis

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  • Objective-C memory management issue

    - by Toby Wilson
    I've created a graphing application that calls a web service. The user can zoom & move around the graph, and the program occasionally makes a decision to call the web service for more data accordingly. This is achieved by the following process: The graph has a render loop which constantly renders the graph, and some decision logic which adds web service call information to a stack. A seperate thread takes the most recent web service call information from the stack, and uses it to make the web service call. The other objects on the stack get binned. The idea of this is to reduce the number of web service calls to only those appropriate, and only one at a time. Right, with the long story out of the way (for which I apologise), here is my memory management problem: The graph has persistant (and suitably locked) NSDate* objects for the currently displayed start & end times of the graph. These are passed into the initialisers for my web service request objects. The web service call objects then retain the dates. After the web service calls have been made (or binned if they were out of date), they release the NSDate*. The graph itself releases and reallocates new NSDates* on the 'touches ended' event. If there is only one web service call object on the stack when removeAllObjects is called, EXC_BAD_ACCESS occurs in the web service call object's deallocation method when it attempts to release the date objects (even though they appear to exist and are in scope in the debugger). If, however, I comment out the release messages from the destructor, no memory leak occurs for one object on the stack being released, but memory leaks occur if there are more than one object on the stack. I have absolutely no idea what is going wrong. It doesn't make a difference what storage symantics I use for the web service call objects dates as they are assigned in the initialiser and then only read (so for correctness' sake are set to readonly). It also doesn't seem to make a difference if I retain or copy the dates in the initialiser (though anything else obviously falls out of scope or is unwantedly released elsewhere and causes a crash). I'm sorry this explanation is long winded, I hope it's sufficiently clear but I'm not gambling on that either I'm afraid. Major big thanks to anyone that can help, even suggest anything I may have missed?

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  • C# chart control Performance with large amounts of data

    - by user3642115
    I am using a chart control with a range bar graph to basically make a gantt chart for lots of people and lots of projects, say about 1000 total series. The issue that I am running in to is that once I have all my data added to the chart, which takes some time but that is to be expected, and I go to scroll down on my graph it freezes the whole application and takes a while before it unfreezes and scrolls down. Is there any way to improve the performance of this? I tried adding the graph to a panel and growing the graph size dynamically and then scrolling down from the panel but that cause a whole plethora of other issues. Any tips for speeding this up? I don't think it is my code as it has already finished running when this issue happens. Thanks.

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  • Depth interpolation for z-buffer, with scanline

    - by Twodordan
    I have to write my own software 3d rasterizer, and so far I am able to project my 3d model made of triangles into 2d space: I rotate, translate and project my points to get a 2d space representation of each triangle. Then, I take the 3 triangle points and I implement the scanline algorithm (using linear interpolation) to find all points[x][y] along the edges(left and right) of the triangles, so that I can scan the triangle horizontally, row by row, and fill it with pixels. This works. Except I have to also implement z-buffering. This means that knowing the rotated&translated z coordinates of the 3 vertices of the triangle, I must interpolate the z coordinate for all other points I find with my scanline algorithm. The concept seems clear enough, I first find Za and Zb with these calculations: var Z_Slope = (bottom_point_z - top_point_z) / (bottom_point_y - top_point_y); var Za = top_point_z + ((current_point_y - top_point_y) * Z_Slope); Then for each Zp I do the same interpolation horizontally: var Z_Slope = (right_z - left_z) / (right_x - left_x); var Zp = left_z + ((current_point_x - left_x) * Z_Slope); And of course I add to the zBuffer, if current z is closer to the viewer than the previous value at that index. (my coordinate system is x: left - right; y: top - bottom; z: your face - computer screen;) The problem is, it goes haywire. The project is here and if you select the "Z-Buffered" radio button, you'll see the results... (note that the rest of the options before "Z-Buffered" use the Painter's algorithm to correctly order the triangles. I also use the painter's algorithm -only- to draw the wireframe in "Z-Buffered" mode for debugging purposes) PS: I've read here that you must turn the z's into their reciprocals (meaning z = 1/z) before you interpolate. I tried that, and it appears that there's no change. What am I missing? (could anyone clarify, precisely where you must turn z into 1/z and where to turn it back?)

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  • Do I need path finding to make AI avoid obstacles?

    - by yannicuLar
    How do you know when a path-finding algorithm is really needed? There are contexts, where you just want to improve AI navigation to avoid an object, like a space -ship that won't crash on a planet or a car that already knows where to steer, but needs small corrections to avoid a road bump. As I've seen on similar posts, the obvious solution is to implement some path-finding algorithm, most likely like A*, and let your AI-controlled object to navigate through the path. Now, I have the necessary skills to implement a path-finding algorithm, and I'm not being lazy here, but I'm still a bit skeptical on if this is really needed. I have the impression that path-finding is appropriate to navigate through a maze, or picking a path when there are many alternatives. But in obstacle avoidance, when you do know the path, but need to make slight corrections, is path finding really necessary? Even when the obstacles are too sparse or small ? I mean, in real life, when you're driving and notice a bump on the road, you will just have to pick between steering a bit on the left (and have the bump on your right side) or the other way around. You will not consider stopping, or going backwards. A path finding would be appropriate when you need to pick a route through the city, right ? So, are there any other methods to help AI navigation, except path-finding? And if there are, how do you know when path-fining is the appropriate algorithm ? Thanks for any thoughts

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  • CodePlex Daily Summary for Wednesday, August 29, 2012

    CodePlex Daily Summary for Wednesday, August 29, 2012Popular ReleasesDiscuzViet: DzX2.5TV Stable Version: Discuz-X2.5-TV-StableMath.NET Numerics: Math.NET Numerics v2.2.1: Major linear algebra rework since v2.1, now available on Codeplex as well (previous versions were only available via NuGet). Since v2.2.0: Student-T density more robust for very large degrees of freedom Sparse Kronecker product much more efficient (now leverages sparsity) Direct access to raw matrix storage implementations for advanced extensibility Now also separate package for signed core library with a strong name (we dropped strong names in v2.2.0) Also available as NuGet packages...Microsoft SQL Server Product Samples: Database: AdventureWorks Databases – 2012, 2008R2 and 2008: About this release This release consolidates AdventureWorks databases for SQL Server 2012, 2008R2 and 2008 versions to one page. Each zip file contains an mdf database file and ldf log file. This should make it easier to find and download AdventureWorks databases since all OLTP versions are on one page. There are no database schema changes. For each release of the product, there is a light-weight and full version of the AdventureWorks sample database. The light-weight version is denoted by ...Smart Thread Pool: SmartThreadPool 2.2.3: Release Changes Added MaxStackSize option to threadsImageServer: v1.1: This is the first version releasedChristoc's DotNetNuke Module Development Template: DotNetNuke Project Templates V1.1 for VS2012: This release is specifically for Visual Studio 2012 Support, distributed through the Visual Studio Extensions gallery at http://visualstudiogallery.msdn.microsoft.com/ After you build in Release mode the installable packages (source/install) can be found in the INSTALL folder now, within your module's folder, not the packages folder anymore Check out the blog post for all of the details about this release. http://www.dotnetnuke.com/Resources/Blogs/EntryId/3471/New-Visual-Studio-2012-Projec...Home Access Plus+: v8.0: v8.0828.1800 RELEASE CHANGED TO BETA Any issues, please log them on http://www.edugeek.net/forums/home-access-plus/ This is full release, NO upgrade ZIP will be provided as most files require replacing. To upgrade from a previous version, delete everything but your AppData folder, extract all but the AppData folder and run your HAP+ install Documentation is supplied in the Web Zip The Quota Services require executing a script to register the service, this can be found in there install di...Phalanger - The PHP Language Compiler for the .NET Framework: 3.0.0.3391 (September 2012): New features: Extended ReflectionClass libxml error handling, constants TreatWarningsAsErrors MSBuild option OnlyPrecompiledCode configuration option; allows to use only compiled code Fixes: ArgsAware exception fix accessing .NET properties bug fix ASP.NET session handler fix for OutOfProc mode Phalanger Tools for Visual Studio: Visual Studio 2010 & 2012 New debugger engine, PHP-like debugging Lot of fixes of project files, formatting, smart indent, colorization etc. Improved ...MabiCommerce: MabiCommerce 1.0.1: What's NewSetup now creates shortcuts Fix spelling errors Minor enhancement to the Map window.ScintillaNET: ScintillaNET 2.5.2: This release has been built from the 2.5 branch. Version 2.5.2 is functionally identical to the 2.5.1 release but also includes the XML documentation comments file generated by Visual Studio. It is not 100% comprehensive but it will give you Visual Studio IntelliSense for a large part of the API. Just make sure the ScintillaNET.xml file is in the same folder as the ScintillaNET.dll reference you're using in your projects. (The XML file does not need to be distributed with your application)....WinRT XAML Toolkit: WinRT XAML Toolkit - 1.2.0: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features AsyncUI extensions Controls and control extensions Converters Debugging helpers Imaging IO helpers VisualTree helpers Samples Recent changes NOTE: Namespace changes DebugConsol...BlackJumboDog: Ver5.7.1: 2012.08.25 Ver5.7.1 (1)?????·?????LING?????????????? (2)SMTP???（????）????、?????\?????????????????????Visual Studio Team Foundation Server Branching and Merging Guide: v2 - Visual Studio 2012: Welcome to the Branching and Merging Guide Quality-Bar Details Documentation has been reviewed by Visual Studio ALM Rangers Documentation has been through an independent technical review Documentation has been reviewed by the quality and recording team All critical bugs have been resolved Known Issues / Bugs Spelling, grammar and content revisions are in progress. Hotfix will be published.MakersEngine: MakersEngine BETA 0.1: First BETA build of MakersEngine Adding TrinityCore compiling support (this should run well on any system) SqlMgr will try to connect to your Database but it wont import anything.Win8GameKit: Windows 8 RTM Release: - Updated for Windows 8 RTM - Fixed Accelerometer Device Check. Gravity Pulse will not be available if no Accelerometer device is present. It will instead ignore any Power ups.SQL Server Keep Alive Service: SQL Server Keep Alive Service 1.0: This is the first official release. Please see the documentation for help https://sqlserverkeepalive.codeplex.com/documentation.ARSoft.Tools.Net - C#/.Net DNS client/server, SPF and SenderID Library: 1.7.0: New Features:Strong name for binary release LLMNR client One-shot Multicast DNS client Some new IPAddress extensions Response validation as described in draft-vixie-dnsext-dns0x20-00 Added support for Owner EDNS option (draft-cheshire-edns0-owner-option) Added support for LLQ EDNS option (draft-sekar-dns-llq) Added support for Update Lease EDNS option (draft-sekar-dns-ul) Changes:Updated to latest IANA parameters Adapted RFC6563 - Moving A6 to Historic Status Use IPv6 addre...7zbackup - PowerShell Script to Backup Files with 7zip: 7zBackup v. 1.8.1 Stable: Do you like this piece of software ? It took some time and effort to develop. Please consider a helping me with a donation Or please visit my blog Code : New work switch maxrecursionlevel to limit recursion depth while searching files to backup Code : rotate argument switch can now be set in selection file too Code : prefix argument switch can now be set in selection file too Code : prefix argument switch is checked against invalid file name chars Code : vars script file has now...Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.62: Fix for issue #18525 - escaped characters in CSS identifiers get double-escaped if the character immediately after the backslash is not normally allowed in an identifier. fixed symbol problem with nuget package. 4.62 should have nuget symbols available again. Also want to highlight again the breaking change introduced in 4.61 regarding the renaming of the DLL from AjaxMin.dll to AjaxMinLibrary.dll to fix strong-name collisions between the DLL and the EXE. Please be aware of this change and...nopCommerce. Open source shopping cart (ASP.NET MVC): nopcommerce 2.65: As some of you may know we were planning to release version 2.70 much later (the end of September). But today we have to release this intermediate version (2.65). It fixes a critical issue caused by a third-party assembly when running nopCommerce on a server with .NET 4.5 installed. No major features have been introduced with this release as our development efforts were focused on further enhancements and fixing bugs. To see the full list of fixes and changes please visit the release notes p...New ProjectsAssociativy: Associativy aims to give a platform for building knowledge bases organized through associative connections. See: http://associativy.comAssociativy Administration: Administration module for the Associativy (http://associativy.com) Orchard graph platform.Associativy Core: Core module for the Associativy (http://associativy.com) Orchard graph platform.Associativy Frontend Engines: Frontend Engines module for the Associativy (http://associativy.com) Orchard graph platform.Associativy Notions Demo Instance: Notions Demo Instance module for the Associativy (http://associativy.com) Orchard graph platform.Associativy Tags Adapter: Tags Adapter module for the Associativy (http://associativy.com) Orchard graph platform.Associativy Tests: Tests module for the Associativy (http://associativy.com) Orchard graph platform.Associativy Web Services: Web Services module for the Associativy (http://associativy.com) Orchard graph platform.DotNMap: A type library that can be used to work with NMap scan results in .net.EFCompoundkeyWhere: ??????????, ??????????? ????????? ??????? Where ?? ?????????? ????? ? Entity FrameworkEntertainment Tools: These are tools for entertainment professionals.EntLib.com????????: ◆ 100% ??(Open Source - ?????)； ◆ ??.Net Framework 4.0； ◆ ?? ASP.NET、C# ?? ? SQL Server ???； ◆ ????????????????????； ◆ ?????????，?????????????；ExpressProfiler: ExpressProfiler is a simple but good enough replacement for SQL Server Profiler Fancy Thumb: Fancy Thumb helps you decorating your thumb drives, giving them fancy icons and names longer than what FAT(32) allows.GEBestBetAdder: GEBestBetAdder is a SharePoint utility which helps with the exporting and importing of keywords and best bets.Ginger Graphics Library: 3D GraphicsImageServer: This is a high performance, high extensible web server writen in ASP.NET C# for image automative processing.jPaint: This is a copy of mspaint, written on pure js + html + css.ListOfTales: This is simple application for store infromation about book))Metro air hockey: metro air hockeyMetro graphcalc: metro graphcalcMetro speedtest: metro speedtestMetro ToDos: metro todosMVC4 Starter Kit: The MVC4 Starter Kit is designed as a bare bone application that covers many of the concerns to be addressed during the first stage of development.MyProject1: MyProject1npantarhei contribute: use the npantarhei flowruntime configured by mef and design your flows within visualstudio 2012 using an integrated designer...PBRX: Powerbuilder to Ruby toolkit.PE file reader: readpe, a tool which parses a PE formatted file and displays the requested information. People: PeoplePocket Calculator: This is POC project that implements a simple WinForms Pocket Calculator that uses a Microsoft .NET 4.0.1 State Machine Workflow in the back-end.ProjectZ: Project Z handles the difficulties with Mologs.PSMNTVIS: this is a blabla test for some blabla code practice.Santry DotNetNuke Lightbox Ad Module: Module allows for you to place a modal ad lightbox module on your DotNetNuke page. It integrates with the HTML provider, and cookie management for display.Sevens' Stories: An album for Class Seven of Pingtan No.1 High School.SIS-TRANSPORTES: Projeto em desenvolvimento...SmartSpace: SmartSpaceSO Chat Star Leaderboard: Scrapes stars from chat.stackoverflow.com and calculates statistics and a leaderboard.testdd08282012git01: dtestdd08282012hg01: uiotestddtfs08282012: kltesttom08282012git01: fdsfdstesttom08282012hg01: ftesttom08282012tfs01: bvcvTransportadoraToledo: Projeto Integrado de SistemasVisual Studio Watchers: Custom Visual Studio visualizers.XNC: XNC is an (in-progress) XNA Framework like library for the C programming language.???: ?

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  • A Cautionary Tale About Multi-Source JNDI Configuration

    - by scott.s.nelson(at)oracle.com
    Here's a bit of fun with WebLogic JDBC configurations.  I ran into this issue after reading that p13nDataSource and cgDataSource-NonXA should not be configured as multi-source. There were some issues changing them to use the basic JDBC connection string and when rolling back to the bad configuration the server went "Boom".  Since one purpose behind this blog is to share lessons learned, I just had to post this. If you write your descriptors manually (as opposed to generating them using the WLS console) and put a comma-separated list of JNDI addresses like this: <jdbc-data-source-params> <jndi-name>weblogic.jdbc.jts.commercePool,contentDataSource, contentVersioningDataSource,portalFrameworkPool</jndi-name> <algorithm-type>Load-Balancing</algorithm-type> <data-source-list>portalDataSource-rac0,portalDataSource-rac1</data-source-list> <failover-request-if-busy>false</failover-request-if-busy> </jdbc-data-source-params> so long as the first address resolves, it will still work. Sort of.  If you call this connection to do an update, only one node of the RAC instance is updated. Other wonderful side-effects include the server refusing to start sometimes. The proper way to list the JNDI sources is one per node, like this: <jdbc-data-source-params> <jndi-name>weblogic.jdbc.jts.commercePool</jndi-name> <jndi-name>contentDataSource</jndi-name> <jndi-name>contentVersioningDataSource</jndi-name> <jndi-name>portalFrameworkPool</jndi-name> <algorithm-type>Load-Balancing</algorithm-type> <data-source-list>portalDataSource-rac0, portalDataSource-rac1, portalDataSource-rac2 </data-source-list> <failover-request-if-busy>false</failover-request-if-busy> </jdbc-data-source-params>(Props to Sandeep Seshan for locating the root cause)

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  • A new mission statement for my school's algorithms class

    - by Eric Fode
    The teacher at Eastern Washington University that is now teaching the algorithms course is new to eastern and as a result the course has changed drastically mostly in the right direction. That being said I feel that the class could use a more specific, and industry oriented (since that is where most students will go, though suggestions for an academia oriented class are also welcome) direction, having only worked in industry for 2 years I would like the community's (a wider and much more collectively experienced and in the end plausibly more credible) opinion on the quality of this as a statement for the purpose an algorithms class, and if I am completely off target your suggestion for the purpose of a required Jr. level Algorithms class that is standalone (so no other classes focusing specifically on algorithms are required). The statement is as follows: The purpose of the algorithms class is to do three things: Primarily, to teach how to learn, do basic analysis, and implement a given algorithm found outside of the class. Secondly, to teach the student how to model a problem in their mind so that they can find a an existing algorithm or have a direction to start the development of a new algorithm. Third, to overview a variety of algorithms that exist and to deeply understand and analyze one algorithm in each of the basic algorithmic design strategies: Divide and Conquer, Reduce and Conquer, Transform and Conquer, Greedy, Brute Force, Iterative Improvement and Dynamic Programming. The Question in short is: do you agree with this statement of the purpose of an algorithms course, so that it would be useful in the real world, if not what would you suggest?

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  • Find points whose pairwise distances approximate a given distance matrix

    - by Stephan Kolassa
    Problem. I have a symmetric distance matrix with entries between zero and one, like this one: D = ( 0.0 0.4 0.0 0.5 ) ( 0.4 0.0 0.2 1.0 ) ( 0.0 0.2 0.0 0.7 ) ( 0.5 1.0 0.7 0.0 ) I would like to find points in the plane that have (approximately) the pairwise distances given in D. I understand that this will usually not be possible with strictly correct distances, so I would be happy with a "good" approximation. My matrices are smallish, no more than 10x10, so performance is not an issue. Question. Does anyone know of an algorithm to do this? Background. I have sets of probability densities between which I calculate Hellinger distances, which I would like to visualize as above. Each set contains no more than 10 densities (see above), but I have a couple of hundred sets. What I did so far. I did consider posting at math.SE, but looking at what gets tagged as "geometry" there, it seems like this kind of computational geometry question would be more on-topic here. If the community thinks this should be migrated, please go ahead. This looks like a straightforward problem in computational geometry, and I would assume that anyone involved in clustering might be interested in such a visualization, but I haven't been able to google anything. One simple approach would be to randomly plonk down points and perturb them until the distance matrix is close to D, e.g., using Simulated Annealing, or run a Genetic Algorithm. I have to admit that I haven't tried that yet, hoping for a smarter way. One specific operationalization of a "good" approximation in the sense above is Problem 4 in the Open Problems section here, with k=2. Now, while finding an algorithm that is guaranteed to find the minimum l1-distance between D and the resulting distance matrix may be an open question, it still seems possible that there at least is some approximation to this optimal solution. If I don't get an answer here, I'll mail the gentleman who posed that problem and ask whether he knows of any approximation algorithm (and post any answer I get to that here).

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  • Rendering a WPF Network Map/Graph layout - Manual? PathListBox? Something Else?

    - by Ben Von Handorf
    I'm writing code to present the user with a simplified network map. At any given time, the map is focused on a specific item... say a router or a server. Based on the focused item, other network entities are grouped into sets (i.e. subnets or domains) and then rendered around the focused item. Lines would represent connections and groups would be visually grouped inside a rectangle or ellipse. Panning and zooming are required features. An item can be selected to display more information in a "properties" style window. An item could also be double-clicked to re-focus the entire network map on that item. At that point, the entire map would be re-calculated. I am using MVVM without any framework, as of yet. Assume the logic for grouping items and determining what should be shown or not is all in place. I'm looking for the best way to approach the UI layout. So far, I'm aware of the following options: Use a canvas for layout (inside a ScrollViewer to handle the panning). Have my ViewModel make use of a Layout Manager type of class, which would handle assigning all the layout properties (Top, Left, etc.). Bind my set of display items to an ItemsControl and use Data Templates to handle the actual rendering. The drawbacks with this approach: Highly manual layout on my part. Lots of calculation. I have to handle item selection manually. Computation of connecting lines is manual. The Pros of this approach: I can draw additional lines between child subnets as appropriate (manually). Additional LayoutManagers could be added later to render the display differently. This could probably be wrapped up into some sort of a GraphLayout control to be re-used. Present the focused item at the center of the display and then use a PathListBox for layout of the additional items. Have my ViewModel expose a simple list of things to be drawn and bind them to the PathListBox. Override the ListBoxItem Template to also create a line geometry from the borders of the focused item (tricky) to the bound item. Use DataTemplates to handle the case where the item being bound is a subnet, in which case we would use another PathListBox in the template to display items inside the subnet. The drawbacks with this approach: Selected Item synchronization across multiple `PathListBox`es. Only one item on the whole graph can be selected at a time, but each child PathListBox maintains its own selection. Also, subnets cannot be selected, but would be selectable without additional work. Drawing the connecting lines is going to be a bit of trickery in the ListBoxItem template, since I need to know the correct side of the focused item to connect to. The pros of this approach: I get to stay out of the layout business, more. I'm looking for any advice or thoughts from others who have encountered similar issues or who have more WPF experience than I. I'm using WPF 4, so any new tricks are legal and encouraged.

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