Search Results

Search found 382 results on 16 pages for 'numerical'.

Page 13/16 | < Previous Page | 9 10 11 12 13 14 15 16  | Next Page >

  • Extra fulltext ordering criteria beyond default relevance

    - by Jeremy Warne
    I'm implementing an ingredient text search, for adding ingredients to a recipe. I've currently got a full text index on the ingredient name, which is stored in a single text field, like so: "Sauce, tomato, lite, Heinz" I've found that because there are a lot of ingredients with very similar names in the database, simply sorting by relevance doesn't work that well a lot of the time. So, I've found myself sorting by a bunch of my own rules of thumb, which probably duplicates a lot of the full-text search algorithm which spits out a numerical relevance. For instance (abridged): ORDER BY [ingredient name is exactly search term], [ingredient name starts with search term], [ingredient name starts with any word from the search and contains all search terms in some order], [ingredient name contains all search terms in some order], ...and so on. Each of these is defined in the SELECT specification as an expression returning either 1 or 0, and so I order by those in sequential order. I would love to hear suggestions for: A better way to define complicated order-by criteria in one place, say perhaps in a view or stored procedure that you can pass just the search term to and get back a set of results without having to worry about how they're ordered? A better tool for this than MySQL's fulltext engine -- perhaps if I was using Sphinx or something [which I've heard of but not used before], would I find some sort of complicated config option designed to solve problems like this? Some google search terms which might turn up discussion on how to order text items within a specific domain like this? I haven't found much that's of use. Thanks for reading!

    Read the article

  • Two strange efficiency problems in Mathematica

    - by Jess Riedel
    FIRST PROBLEM I have timed how long it takes to compute the following statements (where V[x] is a time-intensive function call): Alice = Table[V[i],{i,1,300},{1000}]; Bob = Table[Table[V[i],{i,1,300}],{1000}]^tr; Chris_pre = Table[V[i],{i,1,300}]; Chris = Table[Chris_pre,{1000}]^tr; Alice, Bob, and Chris are identical matricies computed 3 slightly different ways. I find that Chris is computed 1000 times faster than Alice and Bob. It is not surprising that Alice is computed 1000 times slower because, naively, the function V must be called 1000 more times than when Chris is computed. But it is very surprising that Bob is so slow, since he is computed identically to Chris except that Chris stores the intermediate step Chris_pre. Why does Bob evaluate so slowly? SECOND PROBLEM Suppose I want to compile a function in Mathematica of the form f(x)=x+y where "y" is a constant fixed at compile time (but which I prefer not to directly replace in the code with its numerical because I want to be able to easily change it). If y's actual value is y=7.3, and I define f1=Compile[{x},x+y] f2=Compile[{x},x+7.3] then f1 runs 50% slower than f2. How do I make Mathematica replace "y" with "7.3" when f1 is compiled, so that f1 runs as fast as f2? Many thanks!

    Read the article

  • How to solve non-linear equations using python

    - by stars83clouds
    I have the following code: #!/usr/bin/env python from scipy.optimize import fsolve import math h = 6.634e-27 k = 1.38e-16 freq1 = 88633.9360e6 freq2 = 88631.8473e6 freq3 = 88630.4157e6 def J(freq,T): return (h*freq/k)/(math.exp(h*freq/(k*T))-1) def equations(x,y,z,w,a,b,c,d): f1 = a*(J(freq1,y)-J(freq1,2.73))*(1-math.exp(-a*z))-(J(freq2,x)-J(freq2,2.73))*(1-math.exp(-z)) f2 = b*(J(freq3,w)-J(freq3,2.73))*(1-math.exp(-b*z))-(J(freq2,x)-J(freq2,2.73))*(1-math.exp(-z)) f3 = c*(J(freq3,w)-J(freq3,2.73))*(1-math.exp(-b*z))-(J(freq1,y)-J(freq1,2.73))*(1-math.exp(-a*z)) f4 = d*(J((freq3+freq1)/2,(y+w)/2)-J((freq3+freq1)/2,2.73))-(J(freq2,x)-J(freq2,2.73))*(1-math.exp(-z)) return (f1,f2,f3,f4) So, I have defined the equations in the above code. However, I now wish to solve the above set of equations using fsolve or other alternative non-linear numerical routine. I tried the following syntax but with no avail: x,y,z,w = fsolve(equations, (1,1,1,1)) I keep getting the error that "x" is not defined. I am executing all commands at the command-line, since I have no idea how to run a batch of commands as above automatically in python. I welcome any advice on how to solve this.

    Read the article

  • Is there a way to effect user defined data types in MySQL?

    - by Dancrumb
    I have a database which stores (among other things), the following pieces of information: Hardware IDs BIGINTs Storage Capacities BIGINTs Hardware Names VARCHARs World Wide Port Names VARCHARs I'd like to be able to capture a more refined definition of these datatypes. For instance, the hardware IDs have no numerical significance, so I don't care how they are formatted when displayed. The Storage Capacities, however, are cardinal numbers and, at a user's request, I'd like to present them with thousands and decimal separators, e.g. 123,456.789. Thus, I'd like to refine BIGINT into, say ID_NUMBER and CARDINAL. The same with Hardware Names, which are simple text and WWPNs, which are hexstrings, e.g. 24:68:AC:E0. Thus, I'd like to refine VARCHAR into ENGLISH_WORD and HEXSTRING. The specific datatypes I made up are just for illustrative purposes. I'd like to keep all this information in one place and I'm wondering if anybody knows of a good way to hold this all in my MySQL table definitions. I could use the Comment field of the table definition, but that smells fishy to me. One approach would be to define the data structure elsewhere and use that definition to generate my CREATE TABLEs, but that would be a major rework of the code that I currently have, so I'm looking for alternatives. Any suggestions? The application language in use is Perl, if that helps.

    Read the article

  • Properly changing Ajax MultiHandle Slider parameters on postbacks

    - by Matthew PK
    Hi all, In VS2010 I have VB.NET codebehind aspx pages and I'm using Ajax multihandleslider extensions to filter search results on numerical values. Fistly, the multihandle sliders don't display in the designer... I have to remove the slider targets tag: In order to make it display in the designer... this isn't so much a big issue but an annoyance. I am displaying items in a given category. So I get the max and min prices for all items in that category and assign the sliderextension max/min values appropriately. This works fine until... I change the item category and go get a new max/min value for the slider control. I set the max/min values, then I set the target textbox values each to the corresponding max/min values. The slider handles don't repaint (or init?) properly Like say for example my initial min/max is 1/100 if I do a full postback and change the max value to 1000 then the slider bar (correctly) stays the same size but the handle appears WAYYYY to the right off the page and I have to scroll to it. When I click it, it shoots back onto the slider bar. I'm pulling my hair out... why do the slider handles only appear properly when I first set the min/max values?

    Read the article

  • Sorting Arrays by More the One Value, and Prioritizing the Sort based on Column data.

    - by Mark Tomlin
    I'm looking for a way to sort an array (we call this a row), with an array of values (that I'll call columns). Each row has columns that must be sorted based on the priority of: timetime, lapcount & timestamp. Each column cotains this information: split1, split2, split3, laptime, lapcount, timestamp. laptime if in hundredths of a second. (1:23.45 or 1 Minute, 23 Seconds & 45 Hundredths is 8345.) Lapcount is a simple unsigned tiny int, or unsigned char. timestamp is unix epoch. The lowest laptime should be at the get a better standing in this sort. Should two peoples laptimes equal, then timestamp will be used to give the better standing in this sort. Should two peoples timestamp equal, then the person with less of a lapcount get's the better standing in this sort. By better standing, I mean closer to the top of the array, closer to the index of zero where it a numerical array. I think the array sorting functions built into php can do this with a callback, I was wondering what the best approch was for a weighted sort like this would be.

    Read the article

  • Sorting Arrays by More the One Value, and Prioritizing the Sort based on Column data.

    - by Mark Tomlin
    I'm looking for a way to sort an array, based on the information in each row, based on the information in certain cells, that I'll call columns. Each row has columns that must be sorted based on the priority of: timetime, lapcount & timestamp. Each column cotains this information: split1, split2, split3, laptime, lapcount, timestamp. laptime if in hundredths of a second. (1:23.45 or 1 Minute, 23 Seconds & 45 Hundredths is 8345.) Lapcount is a simple unsigned tiny int, or unsigned char. timestamp is unix epoch. The lowest laptime should be at the get a better standing in this sort. Should two peoples laptimes equal, then timestamp will be used to give the better standing in this sort. Should two peoples timestamp equal, then the person with less of a lapcount get's the better standing in this sort. By better standing, I mean closer to the top of the array, closer to the index of zero where it a numerical array. I think the array sorting functions built into php can do this with a callback, I was wondering what the best approch was for a weighted sort like this would be.

    Read the article

  • Polymorphic Numerics on .Net and In C#

    - by Bent Rasmussen
    It's a real shame that in .Net there is no polymorphism for numbers, i.e. no INumeric interface that unifies the different kinds of numerical types such as bool, byte, uint, int, etc. In the extreme one would like a complete package of abstract algebra types. Joe Duffy has an article about the issue: http://www.bluebytesoftware.com/blog/CommentView,guid,14b37ade-3110-4596-9d6e-bacdcd75baa8.aspx How would you express this in C#, in order to retrofit it, without having influence over .Net or C#? I have one idea that involves first defining one or more abstract types (interfaces such as INumeric - or more abstract than that) and then defining structs that implement these and wrap types such as int while providing operations that return the new type (e.g. Integer32 : INumeric; where addition would be defined as public Integer32 Add(Integer32 other) { return Return(Value + other.Value); } I am somewhat afraid of the execution speed of this code but at least it is abstract. No operator overloading goodness... Any other ideas? .Net doesn't look like a viable long-term platform if it cannot have this kind of abstraction I think - and be efficient about it. Abstraction is reuse.

    Read the article

  • JavaScript: input validation in the keydown event

    - by c411
    Hi, I'm attempting to do info validation against user text input in the process of keydown event. The reason that I am trying to validate in the keydown event is because I do not want to display the characters those that are considered to be illegal in the input box at the beginning. The validation I am writing is like this, function validateUserInput(){ var code = this.event.keyCode; if ((code<48||code>57) // numerical &&code!==46 //delete &&code!==8 //back space &&code!==37 // <- arrow &&code!==39) // -> arrow { this.event.preventDefault(); } } I can keep going like this, however I am seeing drawbacks on this implmentation. Those are, for example, Conditional statement become longer and longer when I put more conditions to be examined. keyCodes can be different by browsers. I have to not only check what is not legal but also have to check what are exceptionals. In above examples, delete,backspace, and arrow keys are exceptionals. But the feature that I don't want to lose is having not to display the input in the textarea unless it passes the validation. (In case the user try to put illegal characters in the textarea, nothing should appear at all) That is why I am not doing validation upon keyup event. So my question is, Are there better ways to validate input in keydown event than checking keyCode by keyCode? Are there other ways to capture the user inputs other than keydown event before browser displays it? And a way to put the validation on it? Thanks for the help in advance.

    Read the article

  • SQL UNION ALL problem after using UNION ALL more than 10 times

    - by VBGKM
    I'm getting a formatting problem if I use more than 10 UNION ALL statements in my VBA Code. If I use 10 or less everything works great. What I'm trying to do is combine 12 worksheets (Excel 2007). I have a numerical column called SC that turns into string and date if I have more than 10 UNION ALL. If I try to use ROUND with more than 10 UNION ALL my last selection will change all the records by one unit. I'm using Microsoft.ACE.OLEDB.12.0 as my provider and my connection string has worked for several things in my code so far. Is there any limit for UNION ALL statements when using OLEDB? Here is my code. Dim StrOr As String Dim i As Variant Dim Cnt As ADODB.Connection Dim Rs As ADODB.Recordset For i = 1 To 12 StrOr = StrOr & " " & "SELECT SC FROM [" & MonthName(i, True) & "$" & "] UNION ALL" Next StrOr = Left(StrOr, Len(StrOr) - 9) & ";" Call GetADOCnt Call ADORs

    Read the article

  • Getting started with massive data

    - by Max
    I'm a math guy and occasionally do some statistics/machine learning analysis consulting projects on the side. The data I have access to are usually on the smaller side, at most a couple hundred of megabytes (and almost always far less), but I want to learn more about handling and analyzing data on the gigabyte/terabyte scale. What do I need to know and what are some good resources to learn from? Hadoop/MapReduce is one obvious start. Is there a particular programming language I should pick up? (I primarily work now in Python, Ruby, R, and occasionally Java, but it seems like C and Clojure are often used for large-scale data analysis?) I'm not really familiar with the whole NoSQL movement, except that it's associated with big data. What's a good place to learn about it, and is there a particular implementation (Cassandra, CouchDB, etc.) I should get familiar with? Where can I learn about applying machine learning algorithms to huge amounts of data? My math background is mostly on the theory side, definitely not on the numerical or approximation side, and I'm guessing most of the standard ML algorithms don't really scale. Any other suggestions on things to learn would be great!

    Read the article

  • Is this OleDbDataAdapter bug

    - by ????
    It doesn't look to me OleDbDataAdapter should throw an exception on trying to fill DataSet for a db table column of type decimal(28,3). The message is "The numerical value is too large to fit into a 96 bit decimal". Could you just check this, I have no significant experience with ADO.NET and OLE DB components? The VB.NET code we have in the application is this: Dim dbDataSet As New DataSet Dim dbDataAdapter As OleDbDataAdapter Dim dbCommand As OleDbCommand Dim conn As OleDbConnection Dim connectionString As String 'parts where connectionString is set conn = New OleDbConnection(connectionString) 'part where sqlQuery is set but it ends up being "SELECT Price As 'Price' From PricebookView" - Price is of type decimal(28,3) dbCommand = New OleDbCommand(sqlQuery, conn) dbCommand.CommandTimeout = cmdTimeout dbDataAdapter = New OleDbDataAdapter(dbCommand) dbDataAdapter.Fill(dbDataSet) The last line is where the exception is thrown and the top of the stack trace is: at System.Data.ProviderBase.DbBuffer.ReadNumeric(Int32 offset) at System.Data.OleDb.ColumnBinding.Value_NUMERIC() at System.Data.OleDb.ColumnBinding.Value() at System.Data.OleDb.OleDbDataReader.GetValues(Object[] values) at System.Data.ProviderBase.DataReaderContainer.CommonLanguageSubsetDataReader.GetValues(Object[] values) at System.Data.ProviderBase.SchemaMapping.LoadDataRow() at System.Data.Common.DataAdapter.FillLoadDataRow(SchemaMapping mapping) at System.Data.Common.DataAdapter.FillFromReader(DataSet dataset, DataTable datatable, String srcTable, DataReaderContainer dataReader, Int32 startRecord, Int32 maxRecords, DataColumn parentChapterColumn, Object parentChapterValue) at System.Data.Common.DataAdapter.Fill(DataSet dataSet, String srcTable, IDataReader dataReader, Int32 startRecord, Int32 maxRecords) at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet) ... I am not sure why does it try to set the value to Int32. Thank you for the time !

    Read the article

  • MKL Accelerated Math Libraries for Java...

    - by Kaopua
    I've looked at the related threads on StackOverflow and Googled with not much luck. I'm also very new to Java (I'm coming from a C# and .NET background) so please bear with me. There is so much available in the Java world it's pretty overwhelming. I'm starting on a new Java-on-Linux project that requires some heavy and highly repetitious numerical calculations (i.e. statistics, FFT, Linear Algebra, Matrices, etc.). So maximizing the performance of the mathematical operations is a requirement, as is ensuring the math is correct. So hence I have an interest in finding a Java library that perhaps leverages native acceleration such as MKL, and is proven (so commercial options are definitely a possibility here). In the .NET space there are highly optimized and MKL accelerated commercial Mathematical libraries such as Centerspace NMath and Extreme Optimization. Is there anything comparable in Java? Most of the math libraries I have found for Java either do not seem to be actively maintained (such as Colt) or do not appear to leverage MKL or other native acceleration (such as Apache Commons Math). I have considered trying to leverage MKL directly from Java myself (e.g. JNI), but me being new to Java (let alone interoperating between Java and native libraries) it seemed smarter finding a Java library that has already done this correctly, efficiently, and is proven. Again I apologize if I am mistaken or misguided (even in regarding any libraries I've mentioned) and my ignorance of the Java offerings. It's a whole new world for me coming from the heavily commercialized Microsoft stock so I could easily be mistaken on where to look and regarding the Java libraries I've mentioned. I would greatly appreciate any help or advice.

    Read the article

  • Optimizing processing and management of large Java data arrays

    - by mikera
    I'm writing some pretty CPU-intensive, concurrent numerical code that will process large amounts of data stored in Java arrays (e.g. lots of double[100000]s). Some of the algorithms might run millions of times over several days so getting maximum steady-state performance is a high priority. In essence, each algorithm is a Java object that has an method API something like: public double[] runMyAlgorithm(double[] inputData); or alternatively a reference could be passed to the array to store the output data: public runMyAlgorithm(double[] inputData, double[] outputData); Given this requirement, I'm trying to determine the optimal strategy for allocating / managing array space. Frequently the algorithms will need large amounts of temporary storage space. They will also take large arrays as input and create large arrays as output. Among the options I am considering are: Always allocate new arrays as local variables whenever they are needed (e.g. new double[100000]). Probably the simplest approach, but will produce a lot of garbage. Pre-allocate temporary arrays and store them as final fields in the algorithm object - big downside would be that this would mean that only one thread could run the algorithm at any one time. Keep pre-allocated temporary arrays in ThreadLocal storage, so that a thread can use a fixed amount of temporary array space whenever it needs it. ThreadLocal would be required since multiple threads will be running the same algorithm simultaneously. Pass around lots of arrays as parameters (including the temporary arrays for the algorithm to use). Not good since it will make the algorithm API extremely ugly if the caller has to be responsible for providing temporary array space.... Allocate extremely large arrays (e.g. double[10000000]) but also provide the algorithm with offsets into the array so that different threads will use a different area of the array independently. Will obviously require some code to manage the offsets and allocation of the array ranges. Any thoughts on which approach would be best (and why)?

    Read the article

  • How to get the actual address of a pointer in C?

    - by Airjoe
    BACKGROUND: I'm writing a single level cache simulator in C for a homework assignment, and I've been given code that I must work from. In our discussions of the cache, we were told that the way a small cache can hold large addresses is by splitting the large address into the position in the cache and an identifying tag. That is, if you had an 8 slot cache but wanted to store something with address larger than 8, you take the 3 (because 2^3=8) rightmost bits and put the data in that position; so if you had address 22 for example, binary 10110, you would take those 3 rightmost bits 110, which is decimal 5, and put it in slot 5 of the cache. You would also store in this position the tag, which is the remaining bits 10. One function, cache_load, takes a single argument, and integer pointer. So effectively, I'm being given this int* addr which is an actual address and points to some value. In order to store this value in the cache, I need to split the addr. However, the compiler doesn't like when I try to work with the pointer directly. So, for example, I try to get the position by doing: npos=addr%num_slots The compiler gets angry and gives me errors. I tried casting to an int, but this actually got me the value that the pointer was pointing to, not the numerical address itself. Any help is appreciated, thanks!

    Read the article

  • PHP returns invalid MySQL resource

    - by DeadMG
    $LDATE = '#' . $_REQUEST['LDateDay'] . '/' . $_REQUEST['LDateMonth'] . '/' . $_REQUEST['LDateYear'] . '#'; $RDATE = '#' . $_REQUEST['RDateDay'] . '/' . $_REQUEST['RDateMonth'] . '/' . $_REQUEST['RDateYear'] . '#'; include("../../sql.php"); $myconn2 = mysql_connect(/*removed*/, $username, $password); mysql_select_db(/*removed*/, $myconn2); $LSQLRequest = "SELECT * FROM flight WHERE DepartureDate = ".$LDATE; $LFlights = mysql_query($LSQLRequest, $myconn2); $RSQLRequest = "SELECT * FROM flight WHERE DepartureDate = ".$RDATE; $RFlights = mysql_query($RSQLRequest, $myconn2); Assuming that all the $_REQUESTs are valid numerical values for their appropriate fields in the day/month/year field, how can LFlights and RFlights be invalid? When I polled the whole database I got hundreds of results so I know that the database and connection data is fine, and the field DepartureDate exists too.

    Read the article

  • Easiest way to plot values as symbols in scatter plot?

    - by AllenH
    In an answer to an earlier question of mine regarding fixing the colorspace for scatter images of 4D data, Tom10 suggested plotting values as symbols in order to double-check my data. An excellent idea. I've run some similar demos in the past, but I can't for the life of me find the demo I remember being quite simple. So, what's the easiest way to plot numerical values as the symbol in a scatter plot instead of 'o' for example? Tom10 suggested plt.txt(x,y,value)- and that is the implementation used in a number of examples. I however wonder if there's an easy way to evaluate "value" from my array of numbers? Can one simply say: str(valuearray) ? Do you need a loop to evaluate the values for plotting as suggested in the matplotlib demo section for 3D text scatter plots? Their example produces: However, they're doing something fairly complex in evaluating the locations as well as changing text direction based on data. So, is there a cute way to plot x,y,C data (where C is a value often taken as the color in the plot data- but instead I wish to make the symbol)? Again, I think we have a fair answer to this- I just wonder if there's an easier way?

    Read the article

  • RichFaces a4j:support parameter passing

    - by Mark Lewis
    Hello I have a number of rich:inplaceInput tags in RichFaces which represent numbers in an array. The validator allows integers only. When a user clicks in an input and changes a value, how can I get the bean to sort the array given the new number and reRender the list of rich:inplaceInput tags so that they're in numerical order? EG <a4j:region> <rich:dataTable value="#{MyBacking.config}" var="feed" cellpadding="0" cellspacing="0" width="100%" border="0" columns="5" id="Admin"> ... <a4j:repeat... <a4j:region id="MsgCon"> <rich:inplaceInput value="#{h.id}" validator="#{MyBacking.validateID}" id="andID" showControls="true"> <a4j:support event="onviewactivated" action="#{MyBacking.sort}" reRender="Admin" /> </rich:inplaceInput> </a4j:region> </a4j:repeat> </data:Table> </a4j:region> Note I do NOT want to use dataTable sort functions. The table is complicated and I've specified id="Admin" (ie the whole table) to reRender as I've not found a way to send more localised values to the backing bean through the inplaceInput. This question is about how to use a4j:support action attribute to call the sort method so that when the reRender rerenders the component, it outputs the list in sorted order. I have the sort method working ok when I click a button to sort, but I want to have the list sorted automatically as soon as a new valid value is entered into the inplaceInput component. Thanks

    Read the article

  • Drupal WebForm with CCK content types. For anonymous users.

    - by thepearson
    I am probably asking a noob question... however: I have a Drupal site that the customer has a web form where anonymous users can fill in to order some posters (there is 3 to choose from). These are free and at the moment they user just states in the body of a textarea what posters they want. The site owner wants to now add more posters and now wants the ability to have each poster listed in the web form with a field for quantity next to them. When the web for is submitted it will post the node title and quantity to the web form along with the required information. I have researched using UC but it's too much of a eCom solution for such a simple requirement. I also looked at SimpleCart, Flag and Session favorites, all of which aren't really what I need. So I am looking for a simple way to itterate over all the "Poster" content types, and display them on the webform page with a quantity numerical field to be submitted with the web form for each poster. Currently I have: CCK Poster Title Image WebForm OrderPoster Name Email Address Details What I am looking for is a page that does the following: WebForm OrderPosters: Poster 1 [form qty text input for poster 1] Poster 2 [form qty text input for poster 2] Poster 3 [form qty text input for poster 3] ... Poster n [form qty text input for posters n] Name Email Address Details I'd imagine there is a simple way to do this, but I can't seem to find articles of customizing "WebForm" forms. Any help would be much appreciated.

    Read the article

  • Overlapping template partial specialization when wanting an "override" case: how to avoid the error?

    - by user173342
    I'm dealing with a pretty simple template struct that has an enum value set by whether its 2 template parameters are the same type or not. template<typename T, typename U> struct is_same { enum { value = 0 }; }; template<typename T> struct is_same<T, T> { enum { value = 1 }; }; This is part of a library (Eigen), so I can't alter this design without breaking it. When value == 0, a static assert aborts compilation. So I have a special numerical templated class SpecialCase that can do ops with different specializations of itself. So I set up an override like this: template<typename T> struct SpecialCase { ... }; template<typename LT, typename RT> struct is_same<SpecialCase<LT>, SpecialCase<RT>> { enum { value = 1 }; }; However, this throws the error: more than one partial specialization matches the template argument list Now, I understand why. It's the case where LT == RT, which steps on the toes of is_same<T, T>. What I don't know is how to keep my SpecialCase override and get rid of the error. Is there a trick to get around this? edit: To clarify, I need all cases where LT != RT to also be considered the same (have value 1). Not just LT == RT.

    Read the article

  • How does mercurial's bisect work when the range includes branching?

    - by Joshua Goldberg
    If the bisect range includes multiple branches, how does hg bisect's search work. Does it effectively bisect each sub-branch (I would think that would be inefficient)? For instance, borrowing, with gratitude, a diagram from an answer to this related question, what if the bisect got to changeset 7 on the "good" right-side branch first. @ 12:8ae1fff407c8:bad6 | o 11:27edd4ba0a78:bad5 | o 10:312ba3d6eb29:bad4 |\ | o 9:68ae20ea0c02:good33 | | | o 8:916e977fa594:good32 | | | o 7:b9d00094223f:good31 | | o | 6:a7cab1800465:bad3 | | o | 5:a84e45045a29:bad2 | | o | 4:d0a381a67072:bad1 | | o | 3:54349a6276cc:good4 |/ o 2:4588e394e325:good3 | o 1:de79725cb39a:good2 | o 0:2641cc78ce7a:good1 Will it then look only between 7 and 12, missing the real first-bad that we care about? (thus using "dumb" numerical order) or is it smart enough to use the full topography and to know that the first bad could be below 7 on the right-side branch, or could still be anywhere on the left-side branch. The purpose of my question is both (a) just to understand the algorithm better, and (b) to understand whether I can liberally extend my initial bisect range without thinking hard about what branch I go to. I've been in high-branching bisect situations where it kept asking me after every test to extend beyond the next merge, so that the whole procedure was essentially O(n). I'm wondering if I can just throw the first "good" marker way back past some nest of merges without thinking about it much, and whether that would save time and give correct results.

    Read the article

  • Thread-safety of read-only memory access

    - by Edmund
    I've implemented the Barnes-Hut gravity algorithm in C as follows: Build a tree of clustered stars. For each star, traverse the tree and apply the gravitational forces from each applicable node. Update the star velocities and positions. Stage 2 is the most expensive stage, and so is implemented in parallel by dividing the set of stars. E.g. with 1000 stars and 2 threads, I have one thread processing the first 500 stars and the second thread processing the second 500. In practice this works: it speeds the computation by about 30% with two threads on a two-core machine, compared to the non-threaded version. Additionally, it yields the same numerical results as the original non-threaded version. My concern is that the two threads are accessing the same resource (namely, the tree) simultaneously. I have not added any synchronisation to the thread workers, so it's likely they will attempt to read from the same location at some point. Although access to the tree is strictly read-only I am not 100% sure it's safe. It has worked when I've tested it but I know this is no guarantee of correctness! Questions Do I need to make a private copy of the tree for each thread? Even if it is safe, are there performance problems of accessing the same memory from multiple threads?

    Read the article

  • barebones sort algorithm

    - by user309322
    i have been asked to make a simple sort aglorithm to sort a random series of 6 numbers into numerical order. However i have been asked to do this using "Barebones" a theoretical language put forward in the Book Computer Science an overview. Some information on the language can be found here http://www.brouhaha.com/~eric/software/barebones/ Just to clarify i am a student teacher and have been doing anaysis on "mini-programing languages" and their uses in a teaching environment, i suggested to my tutor that i look at barebones and asked what sort of exmaple program i should write . He suggested a simple sort algorithm. Now since looking at the language i cant understand how i can do this without using arrays and if statements. The code to swap the value of variables would be while a not 0 do; incr Aux1; decr a; end; while b not 0 do; incr Aux2 decr b end; while Aux1 not 0 do; incr a; decr Aux1; end; while Aux2 not 0 do; incr b; decr Aux2; end; however the language does not provide < or operators

    Read the article

  • How to perform Rails model validation checks within model but outside of filters using ledermann-rails-settings and extensions

    - by user1277160
    Background I'm using ledermann-rails-settings (https://github.com/ledermann/rails-settings) on a Rails 2/3 project to extend virtually the model with certain attributes that don't necessarily need to be placed into the DB in a wide table and it's working out swimmingly for our needs. An additional reason I chose this Gem is because of the post How to create a form for the rails-settings plugin which ties ledermann-rails-settings more closely to the model for the purpose of clean form_for usage for administrator GUI support. It's a perfect solution for addressing form_for support although... Something that I'm running into now though is properly validating the dynamic getters/setters before being passed to the ledermann-rails-settings module. At the moment they are saved immediately, regardless if the model validation has actually fired - I can see through script/console that validation errors are being raised. Example For instance I would like to validate that the attribute :foo is within the range of 0..100 for decimal usage (or even a regex). I've found that with the previous post that I can use standard Rails validators (surprise, surprise) but I want to halt on actually saving any values until those are addressed - ensure that the user of the GUI has given 61.43 as a numerical value. The following code has been borrowed from the quoted post. class User < ActiveRecord::Base has_settings validates_inclusion_of :foo, :in => 0..100 def self.settings_attr_accessor(*args) >>SOME SORT OF UNLESS MODEL.VALID? CHECK HERE args.each do |method_name| eval " def #{method_name} self.settings.send(:#{method_name}) end def #{method_name}=(value) self.settings.send(:#{method_name}=, value) end " end >>END UNLESS end settings_attr_accessor :foo end Anyone have any thoughts here on pulling the state of the model at this point outside of having to put this into a before filter? The goal here is to be able to use the standard validations and avoid rolling custom validation checks for each new settings_attr_accessor that is added. Thanks!

    Read the article

  • Defining default value in combobox in CakePHP

    - by Keyur
    <?php echo $form->create('admin_merchant_form', array('action' => '#')); echo $form->input('company_name', array('label' => 'Company Name')); echo $form->input('ac_owner', array('label' => 'Account Owner', 'options' => array('a','b','b'), 'default' => $merchant_select)); echo $form->end('Update'); ?> This is CakePHP code to generate a form with one combobox containing the values "a,b,c" and assigning the default value as $merchant_select which is numerical data. Now the problem is when I assign like 'default'=1 it returns 'b' in the combobox as default value but when writing 'default' = $merchant_select the combobox shows only the first value which is 'a'. The $merchant_select variable is assigned a numeric value equal to merchant's id which 1,2 or 3 when I select any row in the grid. And I also have JavaScript code which alerts with the merchant value when I select any row in the grid so the numeric data is definitely assigned to the $merchant_select variable.

    Read the article

< Previous Page | 9 10 11 12 13 14 15 16  | Next Page >