Search Results

Search found 14861 results on 595 pages for 'high speed computing'.

Page 55/595 | < Previous Page | 51 52 53 54 55 56 57 58 59 60 61 62  | Next Page >

  • High CPU - What to do.

    - by Udi Kantzuker
    I have a high CPU problem with MYSQL using "top" ( linux ) shows cpu peaks of 90%. I was trying to find the source of the problem, turned on general log and slow query log, The slow query log did not find anything. The Db contains a few small tables and one large table that contains almost 100k rows, Database Engine is MyIsam. strange thing i have noticed that on the large table, select, insert are very fast but update takes 0.2 - 0.5 secs. already used optimize and repair and no improvement. the table is being updated frequently, could this be the source of the high CPU% ? What can i do to improve this?

    Read the article

  • iphone best practice, how to load multiple high quality images

    - by bennythemink
    Hi guys and girls, I have about 20-ish high quality images (~3840x5800 px) that I need to load in a simple gallery type app. The user clicks a button and the next image is loaded into the UIImageView. I currently use [UIImage imageWithContentsOfFile:] which takes about 6 seconds to load each image in the simulator :( if I use [UIImage imageNamed:] it takes even longer to load but caches the images which means its quicker if the user wishes to see the same images again. But it may cause memory problems later with all that caching crashing my app. I want to know whats the best practice for loading these? I'm experimenting with reducing image file size as much as is possible but I really need them to be high quality image for the purpose of the app (zoomable, etc.). Thanks for any advice

    Read the article

  • Files served from Apache are slower than other methods

    - by Jiraiya-Sama
    Hi I have a vps with a 1Gb/s line, when running apps on the server I can get (be it not full) reasonable speeds, but when downloading files through apache from this server I never reach close to my line speed usually 600kb/s where I know the line should be able to comfortably do 1MB/s and more. What can I do to increase the download speeds. Is there maybe a freeware or opensource php script that will increase my speeds? Note. I have confirmed that my server can upload at more than 1MB/s, also that I can download at 1MB/s or more. Also I want to increase the speeds without a download accelerator. Thanks for any help.

    Read the article

  • Load balancing Apache on a budget?

    - by Industrial
    Hi everyone, I am trying to get my head around the concept of load balancing to ensure availability and redundancy to keep users happy when things go wrong, rather than load balancing for the sake of offering blistering speed to millions of users. We're on a budget and trying to stick to the stuff where there's plenty of knowledge available, so running Apache on Ubuntu VPS's seems like the strategy until some famous search engine acquire us (Saturday irony included, please note). At least to me, it's a complete jungle of different solutions available. Apaches own mod_proxy & HAproxy are two that we found by a quick google search, but having zero experience of load balancing, I have no idea of what would be appropriate for our situation, or what we would look after while choosing a solution to solve our availability concerns. What is the best option for us? What should we do to get availability high whilst staying inside our budgets?

    Read the article

  • windows is unresponsive but works well in safe mode

    - by kacalapy
    I was installing a few utility apps and things when my laptop running windows 7 stopped responding. I tried to reboot and still very unresponsive... the mouse moves but i am unable to click on icons or open the start menu. eventually things catch up after over a minute. when i start in safe mode with networking support i am able to operate the laptop at lightening speed and web browsing is a dream. I ran msconfig and shut off all non windows services and still get the same thing. after no results i then got and ran spybot, malwarebytes, and other such tools but got no results. they all show nothing wrong. now what?

    Read the article

  • Strategies for very fast delivery of webpages.

    - by Cherian
    I run a website Cucumbertown with an initial pay load of nearly 9KB zipped. All my js is delayed loaded with requirejs and modernizer is the only exception. Now all my webpages are Nginx cached and only 10-15% hits go to the backend proxy. And the cache is invalidated by logged in users as proxy_cache_bypass. So for an anonymous user its nearly always a cache hit. I have some basic OS tuning with default via ip dev eth0 initcwnd 15 net.ipv4.tcp_slow_start_after_idle 0 Despite an all cache & large initcwnd my pages still take 2.5 – 3 seconds. I have a yslow score of And page speed at Are there strategies that can help deliver webpages even faster than this? Deliver pages at 1+ second time for 10KB payload? Notes: My servers run of a fairly good data center from Linode at Fremont.

    Read the article

  • Why maximum 1.0 Gbit Ethernet connection an old notebook, and only 100 Mbit on newer faster computer

    - by Sam
    Strange problem about Ethernet speed: recently we bought an i7 core computer running Win7 64 bit with an onboard Gigabit Ethernet controller (Realtek PCIe Gbit Ethernet Family controller). Connecting this new fast pc directly to our brand new ASUS Gigabit Ethernet router via CAT6 cable(!) shows up the adapter status (see picture attached) only 100mbit, while the router is capable of 1000 mbit. More facts: Connecting an 8 year old IBM notebook with gigabit ethernet to the same cable end shows 1.0 Gbit connection in its adapter status. Speedtest.net shows 35 mbit/s down on the new computer Speedtest.net shows 78 mbit/s down on the old rusty IBM notebook. We have an 120 mbit down internet connection, which we we truly receive on another pc (also directly connected to the router) How to get the 1.0 Gbit going in the new pc ?

    Read the article

  • Are there pitfalls to using incompatible RAM (frequencies) in motherboards?

    - by osij2is
    I'd like to use 2 x 4GB DDR3 1600 dimms in a motherboard capable of only DDR3 1066. The DDR3 1600 is on sale and the cost is identical to 1066 dimms. It'd be nice to have these faster sticks around should i upgrade the motherboard. I assume the RAM can under clock itself or be changed in the BIOS. While obviously it's less than ideal situation, I don't know if there are other unintended consequences in terms of stability, performance and longevity of the board and said RAM. Am I doing any damage to the memory controller or RAM? I've always bought RAM at the max speed specified for the motherboard and I've never gone over so I'm not sure if there any caveats to this at all. Edit: I intend to use the RAM in pairs. I know that mixing RAM speeds is just a bad idea.

    Read the article

  • How to check for bottlenecks in Windows Server 2008 R2

    - by Phil Koury
    I recently switched out a 10 year old server for a brand new server in a small office and upgraded from Windows Server 2000 to Windows Server 2008 R2. After the switch was complete and some configurations were changed around we are running into what appear to be some bottlenecks in the network speed. Accessing programs on the server is slower (resulting in long loading times, slower report generation, etc.) than it was on the old server hardware. I am wondering what options or tools I have, if there are any at all, to find out exactly where these hang ups might be coming from.

    Read the article

  • Lightning fast forum based around metadata / tags? [closed]

    - by Dan W
    I wonder if anything like this exists. I'd like to add a forum to my site, but instead of the usual forum/subforum/sub-subforum structure, I'd like to use a metadata/tag approach where everything exists as a single directory, and where there's a search field at the top which instantly (<0.5 sec) filters the threads to a particular keyword or keywords. Also, as the admin, I would be able to add highly visible buttons at the top, which can be clicked on for the main categories I choose for the forum (nevertheless, users can also add tags to their own threads outside of these default main tags I supply if they wish). This approach, if done properly, is more powerful, efficient, maintenance free, scalable and friendly than a standard forum, so I was hoping someone had the same idea and made something out of it. It couldn't be that hard. I'd want the speed to be up to (or near) the standard of this: http://forum.dlang.org/ Other forums (e.g.: phpBB, shudder) are orders of magnitude worse than that in terms of latency (posting or browsing), and I think that is wrong, even in principle ;)

    Read the article

  • Why is USB-sticks so much slower than Solid State Drives?

    - by Jonas
    From what I understand, USB flash memory and Solid State Drives are based on similar technologies, NAND flash memory. But USB-sticks is usually quite slow with a read and write speed of 5-10MB per second while Solid State Drives usually is very fast, usually 100-570MB per second. Why are Solid State Drives so much faster than USB-sticks? And why isn't USB-sticks faster than 5-10MB per second? Is it simply that SSD-drives uses parallel access to the NAND flash memory or are there other reasons?

    Read the article

  • Suggested benchmark for testing CPU footprint of antivirus software

    - by Alex Chernavsky
    Our organization is currently running Symantec Corporate Antivirus, which is rumored to be a big resource hog. I know that we do have a lot of older machines that are running slow. Our PCs are all running Windows XP Pro and are used only for business applications (mostly Microsoft Office), e-mail, and web surfing. They're not used for gaming (one would hope not, anyway). I'd like to take one of the old PCs and do a speed benchmark test while it's running Symantec AV, then another test with no antivirus, and a third test with ESET NOD32. As I said, I don't care much about graphics performance. What would be an appropriate benchmarking program program to use? Freeware is best, of course. Thank you for considering my question.

    Read the article

  • Speeding up Connection Between Computer and Wireless/Bridged Router

    - by Justian Meyer
    Hey everyone, I looked through other questions, but didn't find useful responses. Our main computer has a dl speed of 6 Mbps, but some of our other computers are getting only 40-200 Kb! The router is wireless, but all computers are connected using a Netgear Wall-Plugged Bridge XE102, which transmits information via the building's powerline. It can't be the hardware itself, however, because some computers still manage decent speeds. The computers afflicted are running on Microsoft XP Service Packs 2 and 3, but so are computers that are totally functional. These speeds severely impede on productivity and are excruciatingly frustrating when trying to cram in time in the early hours. Could it be an issue with the computer? Location? Router? Many thanks in advance, Justian

    Read the article

  • What service can hold CPU at lowest frequency possible when on battery load under Ubuntu?

    - by vava
    When I'm running on battery even with "performance" frequency scaling governor, something regularly lowers CPU speed to it's lowest value. I don't really want that, my AC strip usually in another room so I don't really need to save power. How can I find what service doing that? laptop_mode is disabled so that's not it. Update: Looks like CPU being scaled down only if it is under load. If it is more or less idle, it could stay on any frequency pretty much forever, but once it gets loaded, it quickly jumps to it's lowest frequency. Another update: Something sets maximum frequency CPU can have. Ubuntu launchpad bug 242006

    Read the article

  • Lenovo N100 and Samsung SSD 830, shouldn't this go faster than 100MB/s?

    - by Jook
    I recently upgrated my Lenovo N100 0768 with a Samsung SSD 830 - specified to support 520 MB/s read and 320MB/s write. However, having only SATA1 with max. of 150MB/s speed, it has to run in a slower mode - of course. But, shouldn't it be more on the edge of this limit than ranging between 90-115MB/s and averaging around 103MB/s? Or is this really as much as I can expect? Tested with HD-Tach. Has anyone comparable results on a SATA1 controller with a SSD drive faster than SATA1? Preferably similar to the Samsung 830?

    Read the article

  • Slow slef hosted wordpress website

    - by Integrati Marketing
    Hi All, we have a great site which has been humming along nicely for about 5 months and then in May it went from a page load speed time of 3-5 secs to now an agonising 15+ secs!!! The host has been really helpful and has even shifted the site to a new server which is faster! I guess seeing as though we do not have the insight or your expertise we would ask the Serverfault community and see what this crowd of experts could recommend? Appreciate any insight, thank you. site is here: integrati.com.au Cheers. :)

    Read the article

  • Slow self hosted wordpress website

    - by Integrati Marketing
    Hi All, we have a great site which has been humming along nicely for about 5 months and then in May it went from a page load speed time of 3-5 secs to now an agonising 15+ secs!!! The host has been really helpful and has even shifted the site to a new server which is faster! I guess seeing as though we do not have the insight or your expertise we would ask the Serverfault community and see what this crowd of experts could recommend? Appreciate any insight, thank you. site is here: integrati.com.au Cheers. :)

    Read the article

  • Advice on optimzing speed for a Stored Procedure that uses Views

    - by Belliez
    Based on a previous question and with a lot of help from Damir Sudarevic (thanks) I have the following sql code which works great but is very slow. Can anyone suggest how I can speed this up and optimise for speed. I am now using SQL Server Express 2008 (not 2005 as per my original question). What this code does is retrieves parameters and their associated values from several tables and rotates the table in a form that can be easily compared. Its great for one of two rows of data but now I am testing with 100 rows and to run GetJobParameters takes over 7 minutes to complete? Any advice is gratefully accepted, thank you in advanced. /*********************************************************************************************** ** CREATE A VIEW (VIRTUAL TABLE) TO ALLOW EASIER RETREIVAL OF PARMETERS ************************************************************************************************/ CREATE VIEW dbo.vParameters AS SELECT m.MachineID AS [Machine ID] ,j.JobID AS [Job ID] ,p.ParamID AS [Param ID] ,t.ParamTypeID AS [Param Type ID] ,m.Name AS [Machine Name] ,j.Name AS [Job Name] ,t.Name AS [Param Type Name] ,t.JobDataType AS [Job DataType] ,x.Value AS [Measurement Value] ,x.Unit AS [Unit] ,y.Value AS [JobDataType] FROM dbo.Machines AS m JOIN dbo.JobFiles AS j ON j.MachineID = m.MachineID JOIN dbo.JobParams AS p ON p.JobFileID = j.JobID JOIN dbo.JobParamType AS t ON t.ParamTypeID = p.ParamTypeID LEFT JOIN dbo.JobMeasurement AS x ON x.ParamID = p.ParamID LEFT JOIN dbo.JobTrait AS y ON y.ParamID = p.ParamID GO -- Step 2 CREATE VIEW dbo.vJobValues AS SELECT [Job Name] ,[Param Type Name] ,COALESCE(cast([Measurement Value] AS varchar(50)), [JobDataType]) AS [Val] FROM dbo.vParameters GO /*********************************************************************************************** ** GET JOB PARMETERS FROM THE VIEW JUST CREATED ************************************************************************************************/ CREATE PROCEDURE GetJobParameters AS -- Step 3 DECLARE @Params TABLE ( id int IDENTITY (1,1) ,ParamName varchar(50) ); INSERT INTO @Params (ParamName) SELECT DISTINCT [Name] FROM dbo.JobParamType -- Step 4 DECLARE @qw TABLE( id int IDENTITY (1,1) , txt nchar(300) ) INSERT INTO @qw (txt) SELECT 'SELECT' UNION SELECT '[Job Name]' ; INSERT INTO @qw (txt) SELECT ',MAX(CASE [Param Type Name] WHEN ''' + ParamName + ''' THEN Val ELSE NULL END) AS [' + ParamName + ']' FROM @Params ORDER BY id; INSERT INTO @qw (txt) SELECT 'FROM dbo.vJobValues' UNION SELECT 'GROUP BY [Job Name]' UNION SELECT 'ORDER BY [Job Name]'; -- Step 5 --SELECT txt FROM @qw DECLARE @sql_output VARCHAR (MAX) SET @sql_output = '' -- NULL + '' = NULL, so we need to have a seed SELECT @sql_output = -- string to avoid losing the first line. COALESCE (@sql_output + txt + char (10), '') FROM @qw EXEC (@sql_output) GO

    Read the article

  • Datatable add new column and values speed issue

    - by Cine
    I am having some speed issue with my datatables. In this particular case I am using it as holder of data, it is never used in GUI or any other scenario that actually uses any of the fancy features. In my speed trace, this particular constructor was showing up as a heavy user of time when my database is ~40k rows. The main user was set_Item of DataTable. protected myclass(DataTable dataTable, DataColumn idColumn) { this.dataTable = dataTable; IdColumn = idColumn ?? this.dataTable.Columns.Add(string.Format("SYS_{0}_SYS", Guid.NewGuid()), Type.GetType("System.Int32")); JobIdColumn = this.dataTable.Columns.Add(string.Format("SYS_{0}_SYS", Guid.NewGuid()), Type.GetType("System.Int32")); IsNewColumn = this.dataTable.Columns.Add(string.Format("SYS_{0}_SYS", Guid.NewGuid()), Type.GetType("System.Int32")); int id = 1; foreach (DataRow r in this.dataTable.Rows) { r[JobIdColumn] = id++; r[IsNewColumn] = (r[IdColumn] == null || r[IdColumn].ToString() == string.Empty) ? 1 : 0; } Digging deeper into the trace, it turns out that set_Item calls EndEdit, which brings my thoughts to the transaction support of the DataTable, for which I have no usage for in my scenario. So my solution to this was to open editing on all of the rows and never close them again. _dt.BeginLoadData(); foreach (DataRow row in _dt.Rows) row.BeginEdit(); Is there a better solution? This feels too much like a big giant hack that will eventually come and bite me. You might suggest that I dont use DataTable at all, but I have already considered that and rejected it due to the amount of effort that would be required to reimplement with a custom class. The main reason it is a datatable is that it is ancient code (.net 1.1 time) and I dont want to spend that much time changing it, and it is also because the original table comes out of a third party component.

    Read the article

  • Speed vs security vs compatibility over methods to do string concatenation in Python

    - by Cawas
    Similar questions have been brought (good speed comparison there) on this same subject. Hopefully this question is different and updated to Python 2.6 and 3.0. So far I believe the faster and most compatible method (among different Python versions) is the plain simple + sign: text = "whatever" + " you " + SAY But I keep hearing and reading it's not secure and / or advisable. I'm not even sure how many methods are there to manipulate strings! I could count only about 4: There's interpolation and all its sub-options such as % and format and then there's the simple ones, join and +. Finally, the new approach to string formatting, which is with format, is certainly not good for backwards compatibility at same time making % not good for forward compatibility. But should it be used for every string manipulation, including every concatenation, whenever we restrict ourselves to 3.x only? Well, maybe this is more of a wiki than a question, but I do wish to have an answer on which is the proper usage of each string manipulation method. And which one could be generally used with each focus in mind (best all around for compatibility, for speed and for security). Thanks.

    Read the article

  • Serial.begin(speed, config) not compiling for Leonardo Board

    - by forgemo
    I would like to configure my serial communication to have no parity, 1 start- and 2 stop-bits. The documentation for Serial.begin(speed, config) states: (...) An optional second argument configures the data, parity, and stop bits. The default is 8 data bits, no parity, one stop bit. The documentation also lists the possible configuration-values. According to my (limited) understanding, I need SERIAL_7N2 or SERIAL_8N2 to meet my requirements. (I'm not sure how the data-bits relate to the the 1-start-bit that I need.) However, I can't even compile because I have no idea how to supply that config value to the begin method. (I don't have much Arduino/C++ experience) I've tried in my code the following two variants: Serial.begin(9600, SERIAL_8N2); Serial.begin(9600, "SERIAL_8N2"); Am I missing something? Additional Information: Serial.begin(speed, config) has been introduced with the latest Arduino 1.0.2 IDE version. The code defining/implementing the begin methods can be found here. HardwareSerial.h HardwareSerial.cpp Edit: According to the replies from PeterJ and borges, the following variant is correct. Serial.begin(9600, SERIAL_8N2); However, it's still not working. I found that the compile error doesn't occur if I change the configured board from my Arduino Leonardo to Arduino uno. Therefore, it could be a bug occurring only with a subset of boards ... or maybe it's not supported?!

    Read the article

  • Analyzing Web Application Speed

    - by Amy
    I'm a bit confused because the logical/programmer brain in me says that if all things are constant, the speed of a function must be constant. I am working on a PHP web application with jqGrid as a front end for showing the data. I am testing on my personal computer, so network traffic does not apply. I make an HTTP request to a PHP function, it returns the data, and then jqGrid renders it. What has me befuddled is that sometimes, Firebug reports that this is taking 300-600 milliseconds sometimes, and sometimes, it's taking 3.68 seconds. I can run the request over and over again, with very radically different response times. The query is the same. The number of users on the system is the same. No network latency. Same code. I'm not running other applications on the computer while testing. I could understand query caching improving performance on subsequent requests, but the speed is just fluctuating wildly with no rhyme or reason. So, my question is, what else can cause such variability in the response time? How can I determine what's doing it? More importantly, is there any way to get things more consistent?

    Read the article

  • Which is faster: Appropriate data input or appropriate data structure?

    - by Anon
    I have a dataset whose columns look like this: Consumer ID | Product ID | Time Period | Product Score 1 | 1 | 1 | 2 2 | 1 | 2 | 3 and so on. As part of a program (written in C) I need to process the product scores given by all consumers for a particular product and time period combination for all possible combinations. Suppose that there are 3 products and 2 time periods. Then I need to process the product scores for all possible combinations as shown below: Product ID | Time Period 1 | 1 1 | 2 2 | 1 2 | 2 3 | 1 3 | 2 I will need to process the data along the above lines lots of times ( 10k) and the dataset is fairly large (e.g., 48k consumers, 100 products, 24 time periods etc). So speed is an issue. I came up with two ways to process the data and am wondering which is the faster approach or perhaps it does not matter much? (speed matters but not at the cost of undue maintenance/readability): Sort the data on product id and time period and then loop through the data to extract data for all possible combinations. Store the consumer ids of all consumers who provided product scores for a particular combination of product id and time period and process the data accordingly. Any thoughts? Any other way to speed up the processing? Thanks

    Read the article

  • Autocorrelation returns random results with mic input (using a high pass filter)

    - by Niall
    Hello, Sorry to ask a similar question to the one i asked before (FFT Problem (Returns random results)), but i've looked up pitch detection and autocorrelation and have found some code for pitch detection using autocorrelation. Im trying to do pitch detection of a users singing. Problem is, it keeps returning random results. I've got some code from http://code.google.com/p/yaalp/ which i've converted to C++ and modified (below). My sample rate is 2048, and data size is 1024. I'm detecting pitch of both a sine wave and mic input. The frequency of the sine wave is 726.0, and its detecting it to be 722.950820 (which im ok with), but its detecting the pitch of the mic as a random number from around 100 to around 1050. I'm now using a High pass filter to remove the DC offset, but it's not working. Am i doing it right, and if so, what else can i do to fix it? Any help would be greatly appreciated! double* doHighPassFilter(short *buffer) { // Do FFT: int bufferLength = 1024; float *real = malloc(bufferLength*sizeof(float)); float *real2 = malloc(bufferLength*sizeof(float)); for(int x=0;x<bufferLength;x++) { real[x] = buffer[x]; } fft(real, bufferLength); for(int x=0;x<bufferLength;x+=2) { real2[x] = real[x]; } for (int i=0; i < 30; i++) //Set freqs lower than 30hz to zero to attenuate the low frequencies real2[i] = 0; // Do inverse FFT: inversefft(real2,bufferLength); double* real3 = (double*)real2; return real3; } double DetectPitch(short* data) { int sampleRate = 2048; //Create sine wave double *buffer = malloc(1024*sizeof(short)); double amplitude = 0.25 * 32768; //0.25 * max length of short double frequency = 726.0; for (int n = 0; n < 1024; n++) { buffer[n] = (short)(amplitude * sin((2 * 3.14159265 * n * frequency) / sampleRate)); } doHighPassFilter(data); printf("Pitch from sine wave: %f\n",detectPitchCalculation(buffer, 50.0, 1000.0, 1, 1)); printf("Pitch from mic: %f\n",detectPitchCalculation(data, 50.0, 1000.0, 1, 1)); return 0; } // These work by shifting the signal until it seems to correlate with itself. // In other words if the signal looks very similar to (signal shifted 200 data) than the fundamental period is probably 200 data // Note that the algorithm only works well when there's only one prominent fundamental. // This could be optimized by looking at the rate of change to determine a maximum without testing all periods. double detectPitchCalculation(double* data, double minHz, double maxHz, int nCandidates, int nResolution) { //-------------------------1-------------------------// // note that higher frequency means lower period int nLowPeriodInSamples = hzToPeriodInSamples(maxHz, 2048); int nHiPeriodInSamples = hzToPeriodInSamples(minHz, 2048); if (nHiPeriodInSamples <= nLowPeriodInSamples) printf("Bad range for pitch detection."); if (1024 < nHiPeriodInSamples) printf("Not enough data."); double *results = new double[nHiPeriodInSamples - nLowPeriodInSamples]; //-------------------------2-------------------------// for (int period = nLowPeriodInSamples; period < nHiPeriodInSamples; period += nResolution) { double sum = 0; // for each sample, find correlation. (If they are far apart, small) for (int i = 0; i < 1024 - period; i++) sum += data[i] * data[i + period]; double mean = sum / 1024.0; results[period - nLowPeriodInSamples] = mean; } //-------------------------3-------------------------// // find the best indices int *bestIndices = findBestCandidates(nCandidates, results, nHiPeriodInSamples - nLowPeriodInSamples - 1); //note findBestCandidates modifies parameter // convert back to Hz double *res = new double[nCandidates]; for (int i=0; i < nCandidates;i++) res[i] = periodInSamplesToHz(bestIndices[i]+nLowPeriodInSamples, 2048); double pitch2 = res[0]; free(res); free(results); return pitch2; } /// Finds n "best" values from an array. Returns the indices of the best parts. /// (One way to do this would be to sort the array, but that could take too long. /// Warning: Changes the contents of the array!!! Do not use result array afterwards. int* findBestCandidates(int n, double* inputs,int length) { //int length = inputs.Length; if (length < n) printf("Length of inputs is not long enough."); int *res = new int[n]; double minValue = 0; for (int c = 0; c < n; c++) { // find the highest. double fBestValue = minValue; int nBestIndex = -1; for (int i = 0; i < length; i++) { if (inputs[i] > fBestValue) { nBestIndex = i; fBestValue = inputs[i]; } } // record this highest value res[c] = nBestIndex; // now blank out that index. if(nBestIndex!=-1) inputs[nBestIndex] = minValue; } return res; } int hzToPeriodInSamples(double hz, int sampleRate) { return (int)(1 / (hz / (double)sampleRate)); } double periodInSamplesToHz(int period, int sampleRate) { return 1 / (period / (double)sampleRate); } Thanks, Niall. Edit: Changed the code to implement a high pass filter with a cutoff of 30hz (from What Are High-Pass and Low-Pass Filters?, can anyone tell me how to convert the low-pass filter using convolution to a high-pass one?) but it's still returning random results. Plugging it into a VST host and using VST plugins to compare spectrums isn't an option to me unfortunately.

    Read the article

  • Node.js vs PHP processing speed

    - by Cody Craven
    I've been looking into node.js recently and wanted to see a true comparison of processing speed for PHP vs Node.js. In most of the comparisons I had seen, Node trounced Apache/PHP set ups handily. However all of the tests were small 'hello worlds' that would not accurately reflect any webpage's markup. So I decided to create a basic HTML page with 10,000 hello world paragraph elements. In these tests Node with Cluster was beaten to a pulp by PHP on Nginx utilizing PHP-FPM. So I'm curious if I am misusing Node somehow or if Node is really just this bad at processing power. Note that my results were equivalent outputting "Hello world\n" with text/plain as the HTML, but I only included the HTML as it's closer to the use case I was investigating. My testing box: Core i7-2600 Intel CPU (has 8 threads with 4 cores) 8GB DDR3 RAM Fedora 16 64bit Node.js v0.6.13 Nginx v1.0.13 PHP v5.3.10 (with PHP-FPM) My test scripts: Node.js script var cluster = require('cluster'); var http = require('http'); var numCPUs = require('os').cpus().length; if (cluster.isMaster) { // Fork workers. for (var i = 0; i < numCPUs; i++) { cluster.fork(); } cluster.on('death', function (worker) { console.log('worker ' + worker.pid + ' died'); }); } else { // Worker processes have an HTTP server. http.Server(function (req, res) { res.writeHead(200, {'Content-Type': 'text/html'}); res.write('<html>\n<head>\n<title>Speed test</title>\n</head>\n<body>\n'); for (var i = 0; i < 10000; i++) { res.write('<p>Hello world</p>\n'); } res.end('</body>\n</html>'); }).listen(80); } This script is adapted from Node.js' documentation at http://nodejs.org/docs/latest/api/cluster.html PHP script <?php echo "<html>\n<head>\n<title>Speed test</title>\n</head>\n<body>\n"; for ($i = 0; $i < 10000; $i++) { echo "<p>Hello world</p>\n"; } echo "</body>\n</html>"; My results Node.js $ ab -n 500 -c 20 http://speedtest.dev/ This is ApacheBench, Version 2.3 <$Revision: 655654 $> Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Licensed to The Apache Software Foundation, http://www.apache.org/ Benchmarking speedtest.dev (be patient) Completed 100 requests Completed 200 requests Completed 300 requests Completed 400 requests Completed 500 requests Finished 500 requests Server Software: Server Hostname: speedtest.dev Server Port: 80 Document Path: / Document Length: 190070 bytes Concurrency Level: 20 Time taken for tests: 14.603 seconds Complete requests: 500 Failed requests: 0 Write errors: 0 Total transferred: 95066500 bytes HTML transferred: 95035000 bytes Requests per second: 34.24 [#/sec] (mean) Time per request: 584.123 [ms] (mean) Time per request: 29.206 [ms] (mean, across all concurrent requests) Transfer rate: 6357.45 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.2 0 2 Processing: 94 547 405.4 424 2516 Waiting: 0 331 399.3 216 2284 Total: 95 547 405.4 424 2516 Percentage of the requests served within a certain time (ms) 50% 424 66% 607 75% 733 80% 813 90% 1084 95% 1325 98% 1843 99% 2062 100% 2516 (longest request) PHP/Nginx $ ab -n 500 -c 20 http://speedtest.dev/test.php This is ApacheBench, Version 2.3 <$Revision: 655654 $> Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Licensed to The Apache Software Foundation, http://www.apache.org/ Benchmarking speedtest.dev (be patient) Completed 100 requests Completed 200 requests Completed 300 requests Completed 400 requests Completed 500 requests Finished 500 requests Server Software: nginx/1.0.13 Server Hostname: speedtest.dev Server Port: 80 Document Path: /test.php Document Length: 190070 bytes Concurrency Level: 20 Time taken for tests: 0.130 seconds Complete requests: 500 Failed requests: 0 Write errors: 0 Total transferred: 95109000 bytes HTML transferred: 95035000 bytes Requests per second: 3849.11 [#/sec] (mean) Time per request: 5.196 [ms] (mean) Time per request: 0.260 [ms] (mean, across all concurrent requests) Transfer rate: 715010.65 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.2 0 1 Processing: 3 5 0.7 5 7 Waiting: 1 4 0.7 4 7 Total: 3 5 0.7 5 7 Percentage of the requests served within a certain time (ms) 50% 5 66% 5 75% 5 80% 6 90% 6 95% 6 98% 6 99% 6 100% 7 (longest request) Additional details Again what I'm looking for is to find out if I'm doing something wrong with Node.js or if it is really just that slow compared to PHP on Nginx with FPM. I certainly think Node has a real niche that it could fit well, however with these test results (which I really hope I made a mistake with - as I like the idea of Node) lead me to believe that it is a horrible choice for even a modest processing load when compared to PHP (let alone JVM or various other fast solutions). As a final note, I also tried running an Apache Bench test against node with $ ab -n 20 -c 20 http://speedtest.dev/ and consistently received a total test time of greater than 0.900 seconds.

    Read the article

< Previous Page | 51 52 53 54 55 56 57 58 59 60 61 62  | Next Page >