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Search found 4273 results on 171 pages for 'shift reduce'.

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  • Need Explanation of couchdb reduce function

    - by Alan
    From http://wiki.apache.org/couchdb/Introduction_to_CouchDB_views The couchdb reduce function is defined as function (key, values, rereduce) { return sum(values); } key will be an array whose elements are arrays of the form [key,id] values will be an array of the values emitted for the respective elements in keys i.e. reduce([ [key1,id1], [key2,id2], [key3,id3] ], [value1,value2,value3], false) I am having trouble understanding when/why the array of keys would contain different key values. If the array of keys does contain different key values, how would I deal with it? As an example, assume that my database contains movements between accounts of the form. {"amount":100, "CreditAccount":"account_number", "DebitAccount":"account_number"} I want a view that gives the balance of an account. My map function does: emit( doc.CreditAccount, doc.amount ) emit( doc.DebitAccount, -doc.amount ) My reduce function does: return sum(values); I seem to get the expected results, however I can't reconcile this with the possibility that my reduce function gets different key values. Is my reduce function supposed to group key values first? What kind of result would I return in that case?

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  • reduce memory footprint of java virtual machine

    - by Lorenzo Boccaccia
    I've a citrix server where multiple users use a multiple java application. Is there a way to reduce the memory footprint of the jvm itself? The max heap is already set fairly low (64MB), as the permgen (32MB) space and we're to the point that the jvm itself uses way more memory than the application itself (the committed area is around 350MB) I'm looking for a way to reduce the jvm ram usage or to make the all the applications run within the same jvm or any other way of sharing common pages between running jvm (if possible) or try switch to switch to a jvm if a jvm exists having optimizations relative to this scenario currently using windows 2003 server and sun java virtual machine 1.6

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  • [C#, WinForms] Handle that Shift+F10 w(h)as pressed

    - by Alexander Stalt
    I want to use the exclusive key to open context menu that are available in most of the new laptops and keyboards. This key is usually available between right ALT and CTRL key. I am not sure that it is always equivalent to "Shift + F10" ( or is it always equivalent to "Shift+F10" ?). My programs runs on Windows XP and earlier versions. Context menu should appear at mouse cursor position (if it's possible).

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  • Shift+Tab not working in TreeView control

    - by Christian
    I cannot get backwards navigation using Shift+Tab to work in a TreeView that contains TextBoxs, forward navigation using Tab works fine and jump from TextBox to TextBox inside the TreeView. Anytime Shift+Tab is used when one of the TextBoxes inside the TreeView, then the focus is move to the previous control outside the TreeView, instead of the previous control inside the TreeView. Also its only Shift+Tab navigation that are not working correctly, Ctrl+Shift+Tab work as expected and in the correct order. Any suggestions to what I'm doing wrong? Example code: <Window x:Class="TestTabTreeView.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Window.Resources> <Style TargetType="TreeViewItem"> <Setter Property="KeyboardNavigation.TabNavigation" Value="Continue" /> </Style> </Window.Resources> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="*" /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions> <TextBox Text="First Line" Grid.Row="0" /> <TreeView Grid.Row="1" KeyboardNavigation.TabNavigation="Continue" IsTabStop="False"> <TreeViewItem IsExpanded="True"><TreeViewItem.Header><TextBox Text="Popular Words"/></TreeViewItem.Header> <TreeViewItem><TreeViewItem.Header><TextBox Text="Foo"/></TreeViewItem.Header></TreeViewItem> <TreeViewItem><TreeViewItem.Header><TextBox Text="Bar"/></TreeViewItem.Header></TreeViewItem> <TreeViewItem><TreeViewItem.Header><TextBox Text="Hello"/></TreeViewItem.Header></TreeViewItem> </TreeViewItem> <TreeViewItem IsExpanded="True"><TreeViewItem.Header><TextBox Text="Unpopular Words"/></TreeViewItem.Header> <TreeViewItem><TreeViewItem.Header><TextBox Text="Work"/></TreeViewItem.Header></TreeViewItem> <TreeViewItem><TreeViewItem.Header><TextBox Text="Duplication"/></TreeViewItem.Header></TreeViewItem> </TreeViewItem> </TreeView> <TextBox Text="Last Line" Grid.Row="2" /> </Grid>

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  • Emacs How to redefine Shift-R for expected use

    - by John Bellone
    I've checked my elisp files to make sure that I do not have any bindings that contain Shift+R (and I have not found any). I expect SHIFT+R to print an uppercase character, but instead I get R R undefined inside of the Emacs command line. This is only in C/C++ major modes. Any suggestions? Update: Describing the key shows that it is undefined. How would I define it for the normal, expected use (capitalizing the letter R)?

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  • Circular shift operations in C++

    - by Elroy
    Left and right shift operators (<< and ) are already available in C++. However, I couldn't find out how I could perform circular shift or rotate operations. How can operations like "Rotate Left" and "Rotate Right" be performed? Rotating right twice here Initial --> 1000 0011 0100 0010 should result in: Final --> 1010 0000 1101 0000 An example would be helpful.

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  • Hadoop reduce task gets hung

    - by user806098
    I set up a hadoop cluster with 4 nodes, When running a map-reduce task, the map task finishes quickly, while the reduce task hangs at 27% percent. I checked the log, it's that the reduce task fails to fetch map output from map nodes. The job tracker log of master shows messages like this: 2011-06-27 19:55:14,748 INFO org.apache.hadoop.mapred.JobTracker: Adding task (REDUCE) 'attempt_201106271953_0001_r_000000_0' to tip task_201106271953_0001_r_000000, for tracker 'tracker_web30.bbn.com.cn:localhost/127.0.0.1:56476' And the name node log of master shows messages like this: 2011-06-27 14:00:52,898 INFO org.apache.hadoop.ipc.Server: IPC Server handler 4 on 54310, call register(DatanodeRegistration(202.106.199.39:50010, storageID=DS-1989397900-202.106.199.39-50010-1308723051262, infoPort=50075, ipcPort=50020)) from 192.168.225.19:16129: error: java.io.IOException: verifyNodeRegistration: unknown datanode 202.106.199.3 9:50010 However, neither the "web30.bbn.com.cn" or 202.106.199.39, 202.106.199.3 is the slave node. I think such ip/domains appear because hadoop fails to resolve a node(first in the Intranet DNS server), then it goes to a higher-level DNS server, later to the top, still fails, then the "junk" ip/domains are returned. But I checked my config, it goes like this: /etc/hosts: 127.0.0.1 localhost.localdomain localhost ::1 localhost6.localdomain6 localhost6 192.168.225.16 master 192.168.225.66 slave1 192.168.225.20 slave5 192.168.225.17 slave17 conf/core-site.xml: hadoop.tmp.dir /root/hadoop_tmp/hadoop_${user.name} fs.default.name hdfs://master:54310 io.sort.mb 1024 hdfs-site.xml: dfs.replication 3 masters: master slaves: master slave1 slave5 slave17 Also, all firewalls(iptables) are turned off, and ssh between each 2 nodes is ok. so I don't know where exact the error comes from. Please help. Thanks a lot.

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  • Will An External Audio Interface Reduce CPU Load?

    - by Yar
    I am considering buying a very-low-latency audio interface like this one. One question is if it will reduce CPU load (I'm at about 60%+ and my Macbook has 2.4ghz and 4gigs ram) during intensive audio processing. If the answer is "yes," how will it compare to a different, cheaper firewire audio interface? My thought is that offloading the processing is always the same gain, regardless.

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  • Does BitLocker reduce write reliability?

    - by Unsigned
    For the purposes of this question, BitLocker refers to the BitLocker-to-go variety on a disk with write-caching disabled. NTFS supports metadata journaling, which, although not completely failsafe, does mitigate certain types of potential filesystem errors. Assuming an NTFS volume is protected with BitLocker, does this reduce the failure tolerance? Would a power failure during a write to an NTFS volume, that's protected with BitLocker, be more prone to corruption than on an unencrypted NTFS volume?

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  • Mongo Map Reduce first time

    - by James
    Hello guys, First time Map/Reduce user here, and using MongoDB. I have a lot of page visit data which I'd like to make some sense of by using Map/Reduce. Below is basically what I want to do, but as a total beginner a Map/Reduce, I think this is above my knowledge! Find all visits to current page where external = true within the last 30 days (unix timestamp, I deal with the date ranges in PHP and then the array, not mongo date) Group all visits by referral location For each referral location, calculate how many then went to visit a page which has a certain word in the [tags]. I'm using the normal Mongo PHP extension if that has an impact.

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  • Hadoop WordCount example stuck at map 100% reduce 0%

    - by Abhinav Sharma
    [hadoop-1.0.2] ? hadoop jar hadoop-examples-1.0.2.jar wordcount /user/abhinav/input /user/abhinav/output Warning: $HADOOP_HOME is deprecated. ****hdfs://localhost:54310/user/abhinav/input 12/04/15 15:52:31 INFO input.FileInputFormat: Total input paths to process : 1 12/04/15 15:52:31 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable 12/04/15 15:52:31 WARN snappy.LoadSnappy: Snappy native library not loaded 12/04/15 15:52:31 INFO mapred.JobClient: Running job: job_201204151241_0010 12/04/15 15:52:32 INFO mapred.JobClient: map 0% reduce 0% 12/04/15 15:52:46 INFO mapred.JobClient: map 100% reduce 0% I've set up hadoop on a single node using this guide (http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/#run-the-mapreduce-job) and I'm trying to run a provided example but I'm getting stuck at map 100% reduce 0%. What could be causing this?

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  • shift happens videos

    - by hasan
    im sure you guys must have seen the shift happens video series. here's a link to them : http://www.youtube.com/results?search_query=shift+happens&search_type=&aq=f also, the recent hungry beast video about google, which can be found here: (SO doesnt allow new users more than one hyperlink, so please search on youtube for this one) what i'd like to ask you guys is this: is there a program that enables such videos to be made quickly or is it really just the creative genius of the respective authors? i think vidoes like these are extremely useful when you want to make an impact and would find many uses for such a program in my line of work. im hoping somebody can point me in the right direction. ps. i DO know of animoto, so please dont suggest that :P the problem with animoto is that it doesnt allow text manipulation like these videos. to be fair, that is a great product in itself, but im sure if you take a look, you'll see the difference that im talking abuot.

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  • Why does Perl's shift complain 'Type of arg 1 to shift must be array (not grep iterator).'?

    - by wes
    I've got a data structure that is a hash that contains an array of hashes. I'd like to reach in there and pull out the first hash that matches a value I'm looking for. I tried this: my $result = shift grep {$_->{name} eq 'foo'} @{$hash_ref->{list}}; But that gives me this error: Type of arg 1 to shift must be array (not grep iterator). I've re-read the perldoc for grep and I think what I'm doing makes sense. grep returns a list, right? Is it in the wrong context? I'll use a temporary variable for now, but I'd like to figure out why this doesn't work.

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  • Is there a difference between Perl's shift versus assignment from @_ for subroutine parameters?

    - by cowgod
    Let us ignore for a moment Damian Conway's best practice of no more than three positional parameters for any given subroutine. Is there any difference between the two examples below in regards to performance or functionality? Using shift: sub do_something_fantastical { my $foo = shift; my $bar = shift; my $baz = shift; my $qux = shift; my $quux = shift; my $corge = shift; } Using @_: sub do_something_fantastical { my ($foo, $bar, $baz, $qux, $quux, $corge) = @_; } Provided that both examples are the same in terms of performance and functionality, what do people think about one format over the other? Obviously the example using @_ is fewer lines of code, but isn't it more legible to use shift as shown in the other example? Opinions with good reasoning are welcome.

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  • NASM shift operators

    - by Hudson Worden
    How would you go about doing a bit shift in NASM on a register? I read the manual and it only seems to mention these operators , <<. When I try to use them NASM complains about the shift operator working on scalar values. Can you explain what a scalar value is and give an example of how to use and <<. Also, I thought there were a shr or shl operators. If they do exist can you give an example of how to use them? Thank you for your time.

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  • Getting started with C++ ( the paradigm shift from Python )

    - by orokusaki
    I want to learn C++ so that i can develop C++ Python modules for server-related stuff. I'm a purely dynamic languages developer (Python, PHP, Ruby, etc). I want to learn a fast language, and if I'm going to do this, I'd rather learn a really fast language like C++. Before I even get started though, I understand that suddenly working with static types, a different syntax, and compiling code will be quite the paradigm shift. Is there any advice that a C++ dev who also has dynamic languages experience can give me to me to help me make that shift faster?

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  • Java reduce CPU usage

    - by steve
    Greets- We gots a few nutters in work who enjoy using while(true) { //Code } in their code. As you can imagine this maxes out the CPU. Does anyone know ways to reduce the CPU utilization so that other people can use the server as well. The code itself is just constantly polling the internet for updates on sites. Therefore I'd imagine a little sleep method would greatly reduce the the CPU usage. Also all manipulation is being done in String objects (Java) anyone know how much StringBuilders would reduce the over head by? Thanks for any pointers

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  • Hadoop Map Reduce job never finishes

    - by rohanbk
    I am running a Hadoop Map Reduce job using a Python Mapper and Reducer script, and Hadoop Streaming. Both my Map and Reduce jobs run till they are both 100%, but the job doesn't end. I know that when things go sour, Hadoop will terminate the job, but in this case, both stages reach a 100% and just never end. Has anyone else encountered anything similar? Also, how do I debug my program to figure out where things are going wrong? If I use a smaller input file, and I just run something like: $> cat input_file | mapper.py | sort | reduce.py >> output_file everything works perfectly fine. However, when I use Hadoop, things don't work out.

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  • Javascript Shift+Enter (Firefox)

    - by Stephen MCGinley
    Hi guys, Had a look and found some things on this, but nothing seems to work as I'd like it. Initially I had my solution working with internet explorer and chrome, but not firefox (which is unsatisfactory for me to not have working) What I'm looking for is a simple text area, which sends data on enter key, but creates a new line on Shift+Enter. The following is what I have function goReturn(e,str) { var e = (window.Event) ? e.which : e.keyCode; if (e.shiftKey && e=="13") { document.getElementById("wall").value = document.getElementById("wall").value+"\n"; } else if(e=="13"){ // ...continue to send data } } This sends the data on enter, but also sends the data on shift and enter (which is the problem I have). Thanks for any assistance

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