Search Results

Search found 22897 results on 916 pages for 'query processing'.

Page 157/916 | < Previous Page | 153 154 155 156 157 158 159 160 161 162 163 164  | Next Page >

• Parallelism in Python

  - by fmark

  What are the options for achieving parallelism in Python? I want to perform a bunch of CPU bound calculations over some very large rasters, and would like to parallelise them. Coming from a C background, I am familiar with three approaches to parallelism: Message passing processes, possibly distributed across a cluster, e.g. MPI. Explicit shared memory parallelism, either using pthreads or fork(), pipe(), et. al Implicit shared memory parallelism, using OpenMP. Deciding on an approach to use is an exercise in trade-offs. In Python, what approaches are available and what are their characteristics? Is there a clusterable MPI clone? What are the preferred ways of achieving shared memory parallelism? I have heard reference to problems with the GIL, as well as references to tasklets. In short, what do I need to know about the different parallelization strategies in Python before choosing between them?

  Read the article

• How to display part of an image for the specific width and height?

  - by Brady Chu

  Recently I participated in a web project which has a huge large of images to handle and display on web page, we know that the width and height of images end users uploaded cannot be control easily and then they are hard to display. At first, I attempted to zoom in/out the images to rearch an appropriate presentation, and I made it, but my boss is still not satisfied with my solution, the following is my way: var autoResizeImage = function(maxWidth, maxHeight, objImg) { var img = new Image(); img.src = objImg.src; img.onload = function() { var hRatio; var wRatio; var Ratio = 1; var w = img.width; var h = img.height; wRatio = maxWidth / w; hRatio = maxHeight / h; if (maxWidth == 0 && maxHeight == 0) { Ratio = 1; } else if (maxWidth == 0) { if (hRatio < 1) { Ratio = hRatio; } } else if (maxHeight == 0) { if (wRatio < 1) { Ratio = wRatio; } } else if (wRatio < 1 || hRatio < 1) { Ratio = (wRatio <= hRatio ? wRatio : hRatio); } if (Ratio < 1) { w = w * Ratio; h = h * Ratio; } w = w <= 0 ? 250 : w; h = h <= 0 ? 370 : h; objImg.height = h; objImg.width = w; }; }; This way is only intended to limit the max width and height for the image so that every image in album still has different width and height which are still very urgly. And right at this minute, I know we can create a DIV and use the image as its background image, this way is too complicated and not direct I don't want to take. So I's wondering whether there is a better way to display images with the fixed width and height without presentation distortion? Thanks.

  Read the article

• Simple but efficient way to store a series of small changes to an image?

  - by finnw

  I have a series of images. Each one is typically (but not always) similar to the previous one, with 3 or 4 small rectangular regions updated. I need to record these changes using a minimum of disk space. The source images are not compressed, but I would like the deltas to be compressed. I need to be able to recreate the images exactly as input (so a lossy video codec is not appropriate.) I am thinking of something along the lines of: Composite the new image with a negative of the old image Save the composited image in any common format that can compress using RLE (probably PNG.) Recreate the second image by compositing the previous image with the delta. Although the images have an alpha channel, I can ignore it for the purposes of this function. Is there an easy-to-implement algorithm or free Java library with this capability?

  Read the article

• Matlab - Propagate points orthogonally on to the edge of shape boundaries

  - by Graham

  Hi I have a set of points which I want to propagate on to the edge of shape boundary defined by a binary image. The shape boundary is defined by a 1px wide white edge. I also have the coordinates of these points stored in a 2 row by n column matrix. The shape forms a concave boundary with no holes within itself made of around 2500 points. I want to cast a ray from each point from the set of points in an orthogonal direction and detect at which point it intersects the shape boundary at. What would be the best method to do this? Are there some sort of ray tracing algorithms that could be used? Or would it be a case of taking orthogonal unit vector and multiplying it by a scalar and testing after multiplication if the end point of the vector is outside the shape boundary. When the end point of the unit vector is outside the shape, just find the point of intersection? Thank you very much in advance for any help!

  Read the article

• Understanding CUDA grid dimensions, block dimensions and threads organization (simple explanation)

  - by cibercitizen1

  How threads are organized to be executed by a GPU?

  Read the article

• MySQL slow query

  - by andrhamm

  SELECT items.item_id, items.category_id, items.title, items.description, items.quality, items.type, items.status, items.price, items.posted, items.modified, zip_code.state_prefix, zip_code.city, books.isbn13, books.isbn10, books.authors, books.publisher FROM ( ( items LEFT JOIN bookitems ON items.item_id = bookitems.item_id ) LEFT JOIN books ON books.isbn13 = bookitems.isbn13 ) LEFT JOIN zip_code ON zip_code.zip_code = items.item_zip WHERE items.rid = $rid` I am running this query to get the list of a user's items and their location. The zip_code table has over 40k records and this might be the issue. It currently takes up to 15 seconds to return a list of about 20 items! What can I do to make this query more efficient?

  Read the article

• Good library to load images of different formats

  - by codymanix

  Hi Iam developing an image viewer application just like irfan-view or acdsee which should be capable to view lots of different image file formats (not just the standard ones which can be done with System.Drawing.Image). Iam currently using ImageMagick but it isn't very fast and seems to be unstable with some image files. Can anyone suggest a good imaging library, ideally with a .NET wrapper already present?

  Read the article

• Image coding library

  - by Dmitry

  Is there any good library for lossless image encoding/decoding that has compression rate more or less similar to PNG but decoding to raw RGB bitmap data would be much faster than PNG? Also alpha transparency is needed, but not essential because, alpha channel could be taken from separate image. Original problem lies in slowness of reading and decoding PNG files on iPhone using standard libraries. Obvious and the simples solution would have been storing raw RGB bitmap data, but then size of unpacked ipa is too large - 4 times larger than PNG files. So, I am trying to find some compromise solution.

  Read the article

• How to Use Calculated Color Values with ColorMatrix?

  - by Otaku

  I am changing color values of each pixel in an image based on a calculation. The problem is that this takes over 5 seconds on my machine with a 1000x1333 image and I'm looking for a way to optimize it to be much faster. I think ColorMatrix may be an option, but I'm having a difficult time figure out how I would get a set of pixel RGB values, use that to calculate and then set the new pixel value. I can see how this can be done if I was just modifying (multiplying, subtracting, etc.) the original value with ColorMatrix, but now how I can use the pixels returned value to use it to calculate and new value. For example: Sub DarkenPicture() Dim clrTestFolderPath = "C:\Users\Me\Desktop\ColorTest\" Dim originalPicture = "original.jpg" Dim Luminance As Single Dim bitmapOriginal As Bitmap = Image.FromFile(clrTestFolderPath + originalPicture) Dim Clr As Color Dim newR As Byte Dim newG As Byte Dim newB As Byte For x = 0 To bitmapOriginal.Width - 1 For y = 0 To bitmapOriginal.Height - 1 Clr = bitmapOriginal.GetPixel(x, y) Luminance = ((0.21 * (Clr.R) + (0.72 * (Clr.G)) + (0.07 * (Clr.B))/ 255 newR = Clr.R * Luminance newG = Clr.G * Luminance newB = Clr.B * Luminance bitmapOriginal.SetPixel(x, y, Color.FromArgb(newR, newG, newB)) Next Next bitmapOriginal.Save(clrTestFolderPath + "colorized.jpg", ImageFormat.Jpeg) End Sub The Luminance value is the calculated one. I know I can set ColorMatrix's M00, M11, M22 to 0, 0, 0 respectively and then put a new value in M40, M41, M42, but that new value is calculated based of a value multiplication and addition of that pixel's components (((0.21 * (Clr.R) + (0.72 * (Clr.G)) + (0.07 * (Clr.B)) and the result of that - Luminance - is multiplied by the color component). Is this even possible with ColorMatrix?

  Read the article

• Arduino wireless options

  - by user541597

  I am currently working on a wireless solution for my arduino and computer. I am trying to connect a Transmitter to my computer and a receiver to my arduino. I have seen a lot of examples with arduino to arduino communication but none for computer to arduino. What would I need to interface the transmitter with my computer, PIC? If anyone can provide any insight or any links it would be greatly appreciated. Thanks,

  Read the article

• How do I use CSS to add a non-rectangular border around an image?

  - by KPL

  Hello people, I have three images, and they are not square or rectangular in shape. They are just like face of anyone. So, basically, my images are in the size 196x196 or anything like that, but complete square or rectangle with the face in the middle and transperant background in the rest of the portion. Now, I want to remove the transperant background too and just keep the faces. Don't know if this is possible and mind you, this isn't a programming question. EDIT (from comments): How do I put a border around the shape of the image, not a rectangular one around the boundary, using CSS.

  Read the article

• Optimizing a Soundex Query for finding similar names

  - by xkingpin

  My application will offer a list of suggestions for English names that "sound like" a given typed name. The query will need to be optimized and return results as quick as possible. Which option would be most optimal for returning results quickly. (Or your own suggestion if you have one) A. Generate the Soundex Hash and store it in the "Names" table then do something like the following: (This saves generating the soundex hash for at least every row in my db per query right?) select name from names where NameSoundex = Soundex('Ann') B. Use the Difference function (This must generate the soundex for every name in the table?) select name from names where Difference(name, 'Ann') = 3 C. Simple comparison select name from names where Soundex(name) = Soundex('Ann') Option A seems like to me it would be the fastest to return results because it only generates the Soundex for one string then compares to an indexed column "NameSoundex" Option B should give more results than option A because the name does not have to be an exact match of the soundex, but could be slower Assuming my table could contain millions of rows, what would yield the best results?

  Read the article

• Correct way to Convert 16bit PCM Wave data to float

  - by fredley

  I have a wave file in 16bit PCM form. I've got the raw data in a byte[] and a method for extracting samples, and I need them in float format, i.e. a float[] to do a Fourier Transform. Here's my code, does this look right? I'm working on Android so javax.sound.sampled etc. is not available. private static short getSample(byte[] buffer, int position) { return (short) (((buffer[position + 1] & 0xff) << 8) | (buffer[position] & 0xff)); } ... float[] samples = new float[samplesLength]; for (int i = 0;i<input.length/2;i+=2){ samples[i/2] = (float)getSample(input,i) / (float)Short.MAX_VALUE; }

  Read the article

• Create a SQL query to retrieve most recent records

  - by mattruma

  I am creating a status board module for my project team. The status board allows the user to to set their status as in or out and they can also provide a note. I was planning on storing all the information in a single table ... and example of the data follows: Date User Status Notes ------------------------------------------------------- 1/8/2009 12:00pm B.Sisko In Out to lunch 1/8/2009 8:00am B.Sisko In 1/7/2009 5:00pm B.Sisko In 1/7/2009 8:00am B.Sisko In 1/7/2009 8:00am K.Janeway In 1/5/2009 8:00am K.Janeway In 1/1/2009 8:00am J.Picard Out Vacation I would like to query the data and return the most recent status for each user, in this case, my query would return the following results: Date User Status Notes ------------------------------------------------------- 1/8/2009 12:00pm B.Sisko In Out to lunch 1/7/2009 8:00am K.Janeway In 1/1/2009 8:00am J.Picard Out Vacation I am try to figure out the TRANSACT-SQL to make this happen? Any help would be appreciated.

  Read the article

• Get multiple records with one query

  - by Lewy

  User table: name lastname Bob Presley Jamie Cox Lucy Bush Find users q = Query.new("Bob Presley, Cox, Lucy") q.find_users => {0=>{:name=>"Bob", :lastname=>"Presley"}, 1=>{:lastname=>"Cox"}, 2=>{:name=>"Lucy"}} Question: I've got hash with few names and lastnames. I need to build Activerecord query to fetch all users from that hash. I can do object = [] hash = q.find_users hash.each do |data| #check if data[:lastname] and data[:name] exist # object << User.where(:name => ..., :lastname => ...) end But I think it is higly inefficient. How should I do this ?

  Read the article

• HQL query for entity with max value

  - by Rob

  I have a Hibernate entity that looks like this (accessors ommitted for brevity): @Entity @Table(name="FeatureList_Version") @SecondaryTable(name="FeatureList", pkJoinColumns=@PrimaryKeyJoinColumn(name="FeatureList_Key")) public class FeatureList implements Serializable { @Id @Column(name="FeatureList_Version_Key") private String key; @Column(name="Name",table="FeatureList") private String name; @Column(name="VERSION") private Integer version; } I want to craft an HQL query that retrieves the most up to date version of a FeatureList. The following query sort of works: Select f.name, max(f.version) from FeatureList f group by f.name The trouble is that won't populate the key field, which I need to contain the key of the record with the highest version number for the given FeatureList. If I add f.key in the select it won't work because it's not in the group by or an aggregate and if I put it in the group by the whole thing stops working and it just gives me every version as a separate entity. So, can anybody help?

  Read the article

• Is their an optimal config/format for a TIFF when using Tesseract or other OCR?

  - by Zando

  I'm having a bizarre problem with Tesseract. I have a name, "Janice" that is in a 200x40 pixel tiff, that Tesseract interprets as a blank. I'm running hundreds of names through Tesseract and they are processed fine. What I'm actually doing, though, is breaking up a larger TIFF into smaller tiffs of one word each. In the larger TIFF, tesseract recognizes "Janice". What could cause it to hiccup in a TIFF that solely contains that word (and there's enough space around the word to not truncate any of the pixels)? I'm using ImageMagick to split the big TIFF, are there options I should set when reconstituting the new TIFF files?

  Read the article

• Import Namespace System.Query

  - by GateKiller

  I am trying to load Linq on my .Net 3.5 enabled web server by adding the following to my .aspx page: <%@ Import Namespace="System.Query" %> However, this fails and tells me it cannot find the namespace. The type or namespace name 'Query' does not exist in the namespace 'System' I have also tried with no luck: System.Data.Linq System.Linq System.Xml.Linq I believe that .Net 3.5 is working because var hello = "Hello World" seems to work. Can anyone help please? Cheers, Stephen PS: I just want to clarify that I don't use Visual Studio, I simple have a Text Editor and write my code directly into .aspx files.

  Read the article

• How to retrieve the background color of an arbitary image using MATLAB?

  - by user198729

  This is yet another questions springed from this one, How do I programatically get the background color of an image?

  Read the article

• mysql query: SELECT DISTINCT column1, GROUP BY column2

  - by Adam

  Right now I have the following query: SELECT name, COUNT(name), time, price, ip, SUM(price) FROM tablename WHERE time >= $yesterday AND time <$today GROUP BY name And what I'd like to do is add a DISTINCT by column 'ip', i.e. SELECT DISTINCT ip FROM tablename So my final output would be all the columns, from all the rows that where time is today, grouped by name (with name count for each repeating name) and no duplicate ip addresses. What should my query look like? (or alternatively, how can I add the missing filter to the output with php)? Thanks in advance.

  Read the article

• complex mysql query problem

  - by Scarface

  Hey guys I have a query that selects data and organizes but not in the correct order. What I want to do is select all the comments for a user in that week and sort it by each topic, then sort the cluster by the latest timestamp of each comment in their respective cluster. My current query selects the right data, but in seemingly random order. Does anyone have any ideas? select * from ( SELECT topic.topic_title, topic.topic_id FROM comments JOIN topic ON topic.topic_id=comments.topic_id WHERE comments.user='$user' AND comments.timestamp>$week order by comments.timestamp desc) derived_table group by topic_id

  Read the article

• Nhibernate criteria query inserts an extra order by expression when using JoinType.LeftOuterJoin and Projections

  - by Aaron Palmer

  Why would this nhibernate criteria query produce the sql query below? return Session.CreateCriteria(typeof(FundingCategory), "fc") .CreateCriteria("FundingPrograms", "fp") .CreateCriteria("Projects", "p", JoinType.LeftOuterJoin) .Add(Restrictions.Disjunction() .Add(Restrictions.Eq("fp.Recipient.Id", recipientId)) .Add(Restrictions.Eq("p.Recipient.Id", recipientId)) ) .SetProjection(Projections.ProjectionList() .Add(Projections.GroupProperty("fc.Name"), "fcn") .Add(Projections.Sum("fp.ObligatedAmount"), "fpo") .Add(Projections.Sum("p.ObligatedAmount"), "po") ) .AddOrder(Order.Desc("fpo")) .AddOrder(Order.Desc("po")) .AddOrder(Order.Asc("fcn")) .List<object[]>(); SELECT this_.Name as y0_, sum(fp1_.ObligatedAmount) as y1_, sum(p2_.ObligatedAmount) as y2_ FROM fundingCategories this_ inner join fundingPrograms fp1_ on this_.fundingCategoryId = fp1_.fundingCategoryId left outer join projects p2_ on fp1_.fundingProgramId = p2_.fundingProgramId WHERE (fp1_.recipientId = 6 /* @p0 */ or p2_.recipientId = 6 /* @p1 */) GROUP BY this_.Name ORDER BY p2_.name asc, y1_ desc, y2_ desc, y0_ asc It is incorrectly putting the p2_name asc into the ORDER BY statement, and causing it to crash. This only happens when I use JoinType.LeftOuterJoin on my Projects criteria. Is this a known nhibernate bug? I'm using nhibernate 2.0.1.4000. Thanks for any insight.

  Read the article

• How to convert a 32bpp image to an indexed format?

  - by Ed Swangren

  So here are the details (I am using C# BTW): I receive a 32bpp image (JPEG compressed) from a server. At some point, I would like to use the Palette property of a bitmap to color over-saturated pixels (brightness 240) red. To do so, I need to get the image into an indexed format. I have tried converting the image to a GIF, but I get quality loss. I have tried creating a new bitmap in an index format by these methods: // causes a "Parameter not valid" error Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Indexed) // no error, but the resulting image is black due to information loss I assume Bitmap indexed = new Bitmap(orig.Width, orig.Height, PixelFormat.Format8bppIndexed) I am at a loss now. The data in this image is changed constantly by the user, so I don't want to manually set pixels that have a brightness 240 if I can avoid it. If I can set the palette once when the image is created, my work is done. If I am going about this the wrong way to begin with please let me know. EDIT: Thanks guys, here is some more detail on what I am attempting to accomplish. We are scanning a tissue slide at high resolution (pathology application). I write the interface to the actual scanner. We use a line-scan camera. To test the line rate of the camera, the user scans a very small portion and looks at the image. The image is displayed next to a track bar. When the user moves the track bar (adjusting line rate), I change the overall intensity of the image in an attempt to model what it would look like at the new line rate. I do this using an ImageAttributes and ColorMatrix object currently. When the user adjusts the track bar, I adjust the matrix. This does not give me per pixel information, but the performance is very nice. I could use LockBits and some unsafe code here, but I would rather not rewrite it if possible. When the new image is created, I would like for all pixels with a brightness value of 240 to be colored red. I was thinking that defining a palette for the bitmap up front would be a clean way of doing this.

  Read the article

• Django: query with ManyToManyField count?

  - by AP257

  In Django, how do I construct a COUNT query for a ManyToManyField? My models are as follows, and I want to get all the people whose name starts with A and who are the lord or overlord of at least one Place, and order the results by name. class Manor(models.Model): lord = models.ManyToManyField(Person, null=True, related_name="lord") overlord = models.ManyToManyField(Person, null=True, related_name="overlord") class Person(models.Model): name = models.CharField(max_length=100) So my query should look something like this... but how do I construct the third line? people = Person.objects.filter( Q(name__istartswith='a'), Q(lord.count > 0) | Q(overlord.count > 0) # pseudocode ).order_by('name'))

  Read the article

• Cropping image with ImageScience

  - by fl00r

  ImageScience is cool and light. I am using it in my sinatra app. But I can't understand how can I crop image with not square form and how can I make thumbnail with two dimensions. As I found on ImageScience site: ImageScience.with_image(file) do |img| img.cropped_thumbnail(100) do |thumb| thumb.save "#{file}_cropped.png" end img.thumbnail(100) do |thumb| thumb.save "#{file}_thumb.png" end img.resize(100, 150) do |img2| img2.save "#{file}_resize.png" end end I can crop thumb and resize thumb only with ONE dimension but I want to use two, as in RMagick. For example I want to crop 100x200px box from image, or I want to make thumbnail with width or height not bigger then 300 (width) or 500 (height) pixels.

  Read the article

< Previous Page | 153 154 155 156 157 158 159 160 161 162 163 164  | Next Page >