Search Results

Search found 20847 results on 834 pages for 'advanced computer science'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 76/834 | < Previous Page | 72 73 74 75 76 77 78 79 80 81 82 83  | Next Page >

  • Evolutionary Algorithms: Optimal Repopulation Breakdowns

    - by Brian MacKay
    It's really all in the title, but here's a breakdown for anyone who is interested in Evolutionary Algorithms: In an EA, the basic premise is that you randomly generate a certain number of organisms (which are really just sets of parameters), run them against a problem, and then let the top performers survive. You then repopulate with a combination of crossbreeds of the survivors, mutations of the survivors, and also a certain number of new random organisms. Do that several thousand times, and efficient organisms arise. Some people also do things like introduce multiple "islands" of organisms, which are seperate populations that are allowed to crossbreed once in awhile. So, my question is: what are the optimal repopulation percentages? I have been keeping the top 10% performers, and repopulating with 30% crossbreeds and 30% mutations. The remaining 30% is for new organisms. I have also tried out the multiple island theory, and I'm interested in your results on that as well. It is not lost on me that this is exactly the type of problem an EA could solve. Are you aware of anyone trying that? Thanks in advance!

    Read the article

  • How do I make Linux recognize a new SATA /dev/sda drive I hot swapped in without rebooting?

    - by Philip Durbin
    Hot swapping out a failed SATA /dev/sda drive worked fine, but when I went to swap in a new drive, it wasn't recognized: [root@fs-2 ~]# tail -18 /var/log/messages May 5 16:54:35 fs-2 kernel: ata1: exception Emask 0x10 SAct 0x0 SErr 0x50000 action 0xe frozen May 5 16:54:35 fs-2 kernel: ata1: SError: { PHYRdyChg CommWake } May 5 16:54:40 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:54:45 fs-2 kernel: ata1: device not ready (errno=-16), forcing hardreset May 5 16:54:45 fs-2 kernel: ata1: soft resetting link May 5 16:54:50 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:54:55 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:54:55 fs-2 kernel: ata1: soft resetting link May 5 16:55:00 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:55:05 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:05 fs-2 kernel: ata1: soft resetting link May 5 16:55:10 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:55:40 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:40 fs-2 kernel: ata1: limiting SATA link speed to 1.5 Gbps May 5 16:55:40 fs-2 kernel: ata1: soft resetting link May 5 16:55:45 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:45 fs-2 kernel: ata1: reset failed, giving up May 5 16:55:45 fs-2 kernel: ata1: EH complete I tried a couple things to make the server find the new /dev/sda, such as rescan-scsi-bus.sh but they didn't work: [root@fs-2 ~]# echo "---" > /sys/class/scsi_host/host0/scan -bash: echo: write error: Invalid argument [root@fs-2 ~]# [root@fs-2 ~]# /root/rescan-scsi-bus.sh -l [snip] 0 new device(s) found. 0 device(s) removed. [root@fs-2 ~]# [root@fs-2 ~]# ls /dev/sda ls: /dev/sda: No such file or directory I ended up rebooting the server. /dev/sda was recognized, I fixed the software RAID, and everything is fine now. But for next time, how can I make Linux recognize a new SATA drive I have hot swapped in without rebooting? The operating system in question is RHEL5.3: [root@fs-2 ~]# cat /etc/redhat-release Red Hat Enterprise Linux Server release 5.3 (Tikanga) The hard drive is a Seagate Barracuda ES.2 SATA 3.0-Gb/s 500-GB, model ST3500320NS. Here is the lscpi output: [root@fs-2 ~]# lspci 00:00.0 RAM memory: nVidia Corporation MCP55 Memory Controller (rev a2) 00:01.0 ISA bridge: nVidia Corporation MCP55 LPC Bridge (rev a3) 00:01.1 SMBus: nVidia Corporation MCP55 SMBus (rev a3) 00:02.0 USB Controller: nVidia Corporation MCP55 USB Controller (rev a1) 00:02.1 USB Controller: nVidia Corporation MCP55 USB Controller (rev a2) 00:04.0 IDE interface: nVidia Corporation MCP55 IDE (rev a1) 00:05.0 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.1 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.2 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:06.0 PCI bridge: nVidia Corporation MCP55 PCI bridge (rev a2) 00:08.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:09.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:0a.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0b.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0c.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0d.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0e.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0f.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration 00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map 00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control 00:19.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration 00:19.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map 00:19.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller 00:19.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control 03:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200e [Pilot] ServerEngines (SEP1) (rev 02) 04:00.0 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 04:00.1 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) Update: In perhaps a dozen cases, we've been forced to reboot servers because hot swap hasn't "just worked." Thanks for the answers to look more into the SATA controller. I've included the lspci output for the problematic system above (hostname: fs-2). I could still use some help understanding what exactly isn't supported hardware-wise in terms of hot swap for that system. Please let me know what other output besides lspci might be useful. The good news is that hot swap "just worked" today on one of our servers (hostname: www-1), which is very rare for us. Here is the lspci output: [root@www-1 ~]# lspci 00:00.0 RAM memory: nVidia Corporation MCP55 Memory Controller (rev a2) 00:01.0 ISA bridge: nVidia Corporation MCP55 LPC Bridge (rev a3) 00:01.1 SMBus: nVidia Corporation MCP55 SMBus (rev a3) 00:02.0 USB Controller: nVidia Corporation MCP55 USB Controller (rev a1) 00:02.1 USB Controller: nVidia Corporation MCP55 USB Controller (rev a2) 00:04.0 IDE interface: nVidia Corporation MCP55 IDE (rev a1) 00:05.0 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.1 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.2 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:06.0 PCI bridge: nVidia Corporation MCP55 PCI bridge (rev a2) 00:08.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:09.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:0b.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0c.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0f.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:18.0 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] HyperTransport Configuration 00:18.1 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Address Map 00:18.2 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Miscellaneous Control 00:18.4 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Link Control 00:19.0 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] HyperTransport Configuration 00:19.1 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Address Map 00:19.2 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] DRAM Controller 00:19.3 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Miscellaneous Control 00:19.4 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Link Control 03:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200e [Pilot] ServerEngines (SEP1) (rev 02) 04:00.0 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 04:00.1 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 09:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1064ET PCI-Express Fusion-MPT SAS (rev 04)

    Read the article

  • What is a 'Closure'?

    - by Ben
    I asked a question about Currying and closures where mentioned. What is a closure? How does it relate to currying? Additional: Kyle's answer is great but to my poor procedural/OO mind Ben Childs answer is really useful.

    Read the article

  • JScrollPane Scrolls Down with Long Text in JEditorPane

    - by Jim
    Hello, I want to have a JEditorPane inside a JScrollPane. When the user clicks a button, the click listener will create a textEditor, call jscrollpane.setViewPort(textEditor), call textEditor.setText(String) to fill it with editable text, and call jscrollpane.getVerticalScrollBar().setValue(0). In case you're wondering, yes, the setText() must come after the setViewPort() for reasons that aren't on topic. Here is the problem: After the user clicks the button, the JScrollPane's view scrolls all the way to the bottom. I want the scrollbar to be at the top, as per the last line in my click listener. I popped open a debugger, and to my horror, discovered that the jscrollpane's viewport is being forced down to the bottom after the conclusion of the click listener (when pumping filters). It appears that Swing is delaying the population of the editor/jscrollpane until after the conclusion of the clicklistener, but is calling the scrollbar command first. Thus, the undesired behavior. Anyway, I'm wondering if there is a clean solution. It seems that wanting a scrollpane to be scrolled to the top after modification would be a reasonably common requirement, so I'm assuming this is a well-solved problem. Thanks!

    Read the article

  • What are 'len', 'dir', 'vars' named?

    - by johannix
    I was wondering what language to use when talking about a function that takes in a specific object, acts on it and returns something else. Clearly they're functions, but I was wondering if there's a more specific term. A couple examples of Python built-in functions that fit this spec are: 'len', 'dir', 'vars' I thought it was 'predicate', but apparently that's specific to functions that return a boolean value.

    Read the article

  • Searching, Sorting and Graph Algorithms questions

    - by user177883
    Is there a resource that i can find different variations of searching, sorting and graph algorithm questions ? I have studied CLRS and Algorithm Design by Kleinberg. and solved some set of questions. I have also, checked SO for algorithms questions. Curious, if there is a resource you would highly recommend. EDIT: There is also this free ebook with many questions, that i was able to solve some of them.

    Read the article

  • Netlogo programming question - is it possible to put balanced chemical equations in a model?

    - by user286190
    hi I was wondering if it was possible to put balanced chemical equations, and if possible including state symbols, in the existing netlogo model that i am using, i havenot seen any examples in the models library so was not sure if it was possible. I wanted the model to be able to allow the user to input a balanced chemical equilibrium equation, or the model displays the the equation so then the user can select from them if they do not want to enter their own any help will be greatly appreciated thanks for example ethane + oxygen -- carbon dioxide + steam C2H6 + O2 -- CO2 + H2O

    Read the article

  • merge sort recursion tree height

    - by Tony
    Hello! I am learning about recursion tree's and trying to figure out how the height of the tree is log b of n where n = 2 and one has 10 elements as input size. I am working with Merge sort. The number of times the split is done is the height of the tree as far as I understood, and the number of levels in the tree is height + 1. But if you take (for merge sort) log2 of 10 you get 1, where if you draw the tree you get at least 2 times that the recursion occurs. Where have I gone wrong? (I hope I am making sense here) NOTE: I am doing a self study, this is not homework!

    Read the article

  • Mysql SELECT nested query, very complicated?

    - by smartbear
    Okay, first following are my tables: Table house: id | items_id | 1 | 1,5,10,20 | Table items: id | room_name | refer 1 | kitchen | 3 5 | room1 | 10 Table kitchen: id | detail_name | refer 3 | spoon | 4 5 | fork | 10 Table spoon: id | name | color | price | quantity_available | 4 | spoon_a | white | 50 | 100 | 5 | spoon_b | black | 30 | 200 | How to do a nested select statement, where I want to select id, name, color, price and quantity_available column, from the each value inside the 'items_id' column in 'house' table? This is very challenging!! EDIT: after read robin's answer Table house: id | items_id | house1 | 1 | house1 | 5 | house1 | 10 | house2 | 20 | If this it the house table, how to do the nested, join, or whatever select statement??

    Read the article

  • Software Engineering Papers

    - by kunjaan
    Please recommend me software engineering/methodology/practices paper. So far I have enjoyed: 1968 Dijkstra : Go To Statement Considered Harmful Nikalus Wirth : Program Development by Stepwise Refinement 1971 David Parnas : Information Distribution Aspects of Design Methodology 1972 Liskov : Design Methodology for Reliable Software Systems Extensible Language : Schuman and P Jourrand R. Balzer Structured Programming : Dahl - Hierarchical Program StructuresImplementation Patterns 1971 Jim Morris Protection in Programming Languages 1973 Bill Wulf and Mary Shaw Global Variable Considered Harmful 1974 : Lisko and Zilles ADTs

    Read the article

  • Hidden Features of ASP.NET

    - by Vaibhav
    There are always features that would be useful in fringe scenarios, but for that very reason most people don't know them. I am asking for features that are not typically taught by the text books. What are the ones that you know?

    Read the article

  • CS 50- Pset 1 Mario Program

    - by boametaphysica
    the problem set asks us to create a half pyramid using hashes. Here is a link to an image of how it should look- I get the idea and have written the program until printing the spaces (which I have replaced by "_" just so that I can test the first half of it. However, when I try to run my program, it doesn't go beyond the do-while loop. In other words, it keeps asking me for the height of the pyramid and does not seem to run the for loop at all. I've tried multiple approaches but this problem seems to persist. Any help would be appreciated! Below is my code- # include <cs50.h> # include <stdio.h> int main(void) { int height; do { printf("Enter the height of the pyramid: "); height = GetInt(); } while (height > 0 || height < 24); for (int rows = 1; rows <= height, rows++) { for (int spaces = height - rows; spaces > 0; spaces--) { printf("_"); } } return 0; } Running this program yields the following output- Enter the height of the pyramid: 11 Enter the height of the pyramid: 1231 Enter the height of the pyramid: aawfaf Retry: 12 Enter the height of the pyramid:

    Read the article

  • Is there any need to get a Computer Science degree?

    - by Tom Moseley
    I've been a software developer for 20 years. i've been involved in language development and large data warehouse development. I've worked for start-ups that have gone public, and for government contractors, and I've written a published programming book. My knowledge is either self-taught or on-the-job. I've worked with some of the best and brightest, and they taught me well. I'm back in school now, and am weighing my options, deciding between a Computer Science and a business degree. My question is this. What do I gain, at this point in my career, by earning a Computer Science degree? I just don't know if a Computer Science degree, at this point, is a value-add on my resume. Edit: I'm working on completing an undergraduate degree.

    Read the article

  • Proving that P <= NP

    - by Gail
    As most people know, P = NP is unproven and seems unlikely to be true. The proof would prove that P <= NP and NP <= P. Only one of those is hard, though. P <= NP is almost by definition true. In fact, that's the only way that I know how to state that P <= NP. It's just intuitive. How would you prove that P <= NP?

    Read the article

  • Complex behavior generated by simple computation

    - by Yuval A
    Stephen Wolfram gave a fascinating talk at TED about his work with Mathematica and Wolfram Alpha. Amongst other things, he pointed out how very simple computations can yield extremely complex behaviors. (He goes on to discuss his ambition for computing the entire physical universe. Say what you will, you gotta give the guy some credit for his wild ideas...) As an example he showed several cellular automata. What other examples of simple computations do you know of that yield fascinating results?

    Read the article

  • Power of programming languages

    - by Casebash
    Are there any objective measures for measuring the power of programming languages? Turing-completeness is one, but it is not particularly discriminating. I also remember there being a few others measures of power which are more limited versions (like finite-state-autonoma), but is there any objective measure that is more powerful?

    Read the article

  • Code Golf: Shortest Turing-complete interpreter.

    - by ilya n.
    I've just tried to create the smallest possible language interpreter. Would you like to join and try? Rules of the game: You should specify a programming language you're interpreting. If it's a language you invented, it should come with a list of commands in the comments. Your code should start with example program and data assigned to your code and data variables. Your code should end with output of your result. It's preferable that there are debug statements at every intermediate step. Your code should be runnable as written. You can assume that data are 0 and 1s (int, string or boolean, your choice) and output is a single bit. The language should be Turing-complete in the sense that for any algorithm written on a standard model, such as Turing machine, Markov chains, or similar of your choice, it's reasonably obvious (or explained) how to write a program that after being executred by your interpreter performs the algorithm. The length of the code is defined as the length of the code after removal of input part, output part, debug statements and non-necessary whitespaces. Please add the resulting code and its length to the post. You can't use functions that make compiler execute code for you, such as eval(), exec() or similar. This is a Community Wiki, meaning neither the question nor answers get the reputation points from votes. But vote anyway!

    Read the article

  • Direct TCP/IP connections in P2P apps

    - by Greg Roberts
    From a Joel's post on Copilot: Direct Connect! We’ve always done everything we can to make sure that Fog Creek Copilot can connect in any networking situation, no matter what firewalls or NATs are in place. To make this happen, both parties make outbound connections to our server, which relays traffic on their behalf. Well, in many cases, this isn’t necessary. So version 2.0 does something rather clever: it sets up the initial connection through our servers, so you get connected right away with 100% reliability. But then once you’re all connected, it quietly, in the background, looks for a way to make a direct connection. If it can’t, no big deal: you just keep relaying through our server. If you can make a direct peer-to-peer connection, it silently shifts your data onto the direct connection. You won’t notice anything except, probably, much faster communication. How do they change the server connection to a P2P connection?

    Read the article

  • Access modifiers in Object-Oriented Programming

    - by Imran
    I don't understand Access Modifiers in OOP. Why do we make for example in Java instance variables private and then use public getter and setter methods to access them? I mean what's the reasoning/logic behind this? You still get to the instance variable but why use setter and getter methods when you can just make your variables public? please excuse my ignorance as I am simply trying to understand why? Thank you in advance. ;-)

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 72 73 74 75 76 77 78 79 80 81 82 83  | Next Page >