Search Results

Search found 552 results on 23 pages for 'hungarian notation'.

Page 18/23 | < Previous Page | 14 15 16 17 18 19 20 21 22 23  | Next Page >

• Which version of Grady Booch's OOA/D book should I buy?

  - by jackj

  Grady Booch's "Object-Oriented Analysis and Design with Applications" is available brand new in both the 2nd edition (1993) and the 3rd edition (2007), while many used copies of both editions are available. Here are my concerns: 1) The 2nd edition uses C++: given that I just finished reading my first two C++ books (Accelerated C++ and C++ Primer) I guess practical tips can only help, so the 2nd edition is probably best (I think the 3rd edition has absolutely no code). On the other hand, the C++ books I read insist on the importance of using standard C++, whereas Booch's 2nd edition was published before the 1998 standard. 2) The 2nd edition is shorter (608 pages vs. 720) so, I guess, it will be slightly easier to get through. 3) The 3rd edition uses UML 2.0, whereas the 2nd edition is pre-UML. Some reviews say that the notation in the 2nd edition is close enough to UML, so it doesn't matter, but I don't know if I should be worrying about this or not. 4) The 2nd edition is available in good-shape used copies for considerably less than what the 3rd one goes for. Given all the above factors, do you think I should buy the 2nd or the 3rd edition? Recommendations on other books are also welcome but I would prefer it if whoever answers has read at least one of the versions of Booch's book (preferably both!). I have already bought but not read GoF and Riel's books. I also know that I should practice a lot with real-life code. Thanks.

  Read the article

• HTML Form HIdden Fields added with Javascript not POSTing

  - by dscher

  I have a form where the user can enter a link, click the "add link" button, and that link is then(via jQuery) added to the form as a hidden field. The problem is it's not POSTing when I submit the form. It's really starting to confound me. The thing is that if I hardcode a hidden field into the form, it is posted, but my function isn't working for some reason. The hidden field DOES get added to my form as I can see with Firebug but it's just not being sent with the POST data. Just to note, I'm using an array in Javascript to hold the elements until the form is submitted which also posts them visibly for the user to see what they've added. I'm using [] notation on the "name" field of the element because I want the links to feed into an array in PHP. Here is the link creation which is being appended to my form: function make_hidden_element_tag(item_type, item_content, item_id) { return '<input type="hidden" name="' + item_type + '[]" id="hidden_link_' + item_id + '" value="' + item_content + '"/>'; Does anyone have an idea why this might not be posting. As stated above, any hard-coded tags that are nearly identical to the above works fine, it's just that this tag isn't working. Here is how I'm adding the tag to the form with jQUery: $('#link_td').append( make_hidden_element_tag('links', link, link_array.length - 1)); I'm using the Kohana 3 framework, although I'm not sure that has any bearing on this because it's not really doing anything from the time the HTML is added to the page and the submit button is pressed.

  Read the article

• Architecture for data layer that uses both localStorage and a REST remote server

  - by Zack

  Anybody has any ideas or references on how to implement a data persistence layer that uses both a localStorage and a REST remote storage: The data of a certain client is stored with localStorage (using an ember-data indexedDB adapter). The locally stored data is synced with the remote server (using ember-data RESTadapter). The server gathers all data from clients. Using mathematical sets notation: Server = Client1 ? Client2 ? ... ? ClientN where, in general, a record may not be unique to a certain client. Here are some scenarios: A client creates a record. The id of the record can not set on the client, since it may conflict with a record stored on the server. Therefore a newly created record needs to be committed to the server - receive the id - create the record in localStorage. A record is updated on the server, and as a consequence the data in localStorage and in the server go out of sync. Only the server knows that, so the architecture needs to implement a push architecture (?) Would you use 2 stores (one for localStorage, one for REST) and sync between them, or use a hybrid indexedDB/REST adapter and write the sync code within the adapter? Can you see any way to avoid implementing push (Web Sockets, ...)?

  Read the article

• Are functional programming languages good for practical tasks?

  - by Clueless

  It seems to me from my experimenting with Haskell, Erlang and Scheme that functional programming languages are a fantastic way to answer scientific questions. For example, taking a small set of data and performing some extensive analysis on it to return a significant answer. It's great for working through some tough Project Euler questions or trying out the Google Code Jam in an original way. At the same time it seems that by their very nature, they are more suited to finding analytical solutions than actually performing practical tasks. I noticed this most strongly in Haskell, where everything is evaluated lazily and your whole program boils down to one giant analytical solution for some given data that you either hard-code into the program or tack on messily through Haskell's limited IO capabilities. Basically, the tasks I would call 'practical' such as Aceept a request, find and process requested data, and return it formatted as needed seem to translate much more directly into procedural languages. The most luck I have had finding a functional language that works like this is Factor, which I would liken to a reverse-polish-notation version of Python. So I am just curious whether I have missed something in these languages or I am just way off the ball in how I ask this question. Does anyone have examples of functional languages that are great at performing practical tasks or practical tasks that are best performed by functional languages?

  Read the article

• visualising piano performance evaluation

  - by Dolphin

  I need to develop a performance evaluator for piano playing. Based on a midi generated from sheet music, I need to evaluate the midi of the actual playing (midi keyboard). I'm planning to evaluate the playing based on note pitch, duration and loudness. The evaluation is I suppose a comparison of the notes of the sheet music and playing in midi. But I have no idea how I can visualise (i.e. show where the person have gone wrong) this evaluation process. i.e. maybe show both the notation and highlight which note has gone wrong. But how can I show any of this in some graphical form? Or more precisely on a stave (a music score) itself. I have note details (pitch, duration) and score details (key and time signature) stored in a table, and I'm using Java. But I have no clue as in how I can put all this into graphical form. Any insight is most gratefully appreciated. Advance thanks

  Read the article

• Mulit-dimensional array edge/border conditions

  - by kirbuchi

  Hi, I'm iterating over a 3 dimensional array (which is an image with 3 values for each pixel) to apply a 3x3 filter to each pixel as follows: //For each value on the image for (i=0;i<3*width*height;i++){ //For each filter value for (j=0;j<9;j++){ if (notOutsideEdgesCondition){ *(**(outArray)+i)+= *(**(pixelArray)+i-1+(j%3)) * (*(filter+j)); } } } I'm using pointer arithmetic because if I used array notation I'd have 4 loops and I'm trying to have the least possible number of loops. My problem is my notOutsideEdgesCondition is getting quite out of hands because I have to consider 8 border cases. I have the following handled conditions Left Column: ((i%width)==0) && (j%3==0) Right Column: ((i-1)%width ==0) && (i>1) && (j%3==2) Upper Row: (i<width) && (j<2) Lower Row: (i>(width*height-width)) && (j>5) and still have to consider the 4 corner cases which will have longer expressions. At this point I've stopped and asked myself if this is the best way to go because If I have a 5 line long conditional evaluation it'll not only be truly painful to debug but will slow the inner loop. That's why I come to you to ask if there's a known algorithm to handle this cases or if there's a better approach for my problem. Thanks a lot.

  Read the article

• Calculating rotation in > 360 deg. situations

  - by danglebrush

  I'm trying to work out a problem I'm having with degrees. I have data that is a list of of angles, in standard degree notation -- e.g. 26 deg. Usually when dealing with angles, if an angle exceeds 360 deg then the angle continues around and effectively "resets" -- i.e. the angle "starts again", e.g. 357 deg, 358 deg, 359 deg, 0 deg, 1 deg, etc. What I want to happen is the degree to continue increasing -- i.e. 357 deg, 358 deg, 359 deg, 360 deg, 361 deg, etc. I want to modify my data so that I have this converted data in it. When numbers approach the 0 deg limit, I want them to become negative -- i.e. 3 deg, 2 deg, 1 deg, 0 deg, -1 deg, -2 deg, etc. With multiples of 360 deg (both positive and negative), I want the degrees to continue, e.g. 720 deg, etc. Any suggestions on what approach to take? There is, no doubt, a frustratingly simple way of doing this, but my current solution is kludgey to say the least .... ! My best attempt to date is to look at the percentage difference between angle n and angle n - 1. If this is a large difference -- e.g. 60% -- then this needs to be modified, by adding or subtracting 360 deg to the current value, depending on the previous angle value. That is, if the previous angle is negative, substract 360, and add 360 if the previous angle is positive. Any suggestions on improving this? Any improvements?

  Read the article

• why limxml2 quotes starting double slash in CDATA with javascript

  - by Vincenzo

  This is my code: <?php $data = <<<EOL <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html> <script type="text/javascript"> //<![CDATA[ var a = 123; // JS code //]]> </script> </html> EOL; $dom = new DOMDocument(); $dom->preserveWhiteSpace = false; $dom->formatOutput = false; $dom->loadXml($data); echo '<pre>' . htmlspecialchars($dom->saveXML()) . '</pre>'; This is result: <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <script type="text/javascript"><![CDATA[ //]]><![CDATA[ var a = 123; // JS code //]]><![CDATA[ ]]></script></html> If and when I remove the DOCTYPE notation from XML document, CDATA works properly and leading/trailing double slash is not turned into CDATA. What is the problem here? Bug in libxml2? PHP version is 5.2.13 on Linux. Thanks.

  Read the article

• How do I best do balanced quoting with Perl's Regexp::Grammars?

  - by Evan Carroll

  Using Damian Conway's Regexp::Grammars, I'm trying to match different balanced quoting ('foo', "foo", but not 'foo") mechanisms -- such as parens, quotes, double quotes, and double dollars. This is the code I'm currently using. <token: pair> \'<literal>\'|\"<literal>\"|\$\$<literal>\$\$ <token: literal> [\S]+ This generally works fine and allows me to say something like: <rule: quote> QUOTE <.as>? <pair> My question is how do I reform the output, to exclude the needles notation for the pair token? { '' => 'QUOTE AS \',\'', 'quote' => { '' => 'QUOTE AS \',\'', 'pair' => { 'literal' => ',', '' => '\',\'' } } }, Here, there is obviously no desire to have pair in between, quote, and the literal value of it. Is there a better way to match 'foo', "foo", and $$foo$$, and maybe sometimes ( foo ) without each time creating a needless pair token? Can I preprocess-out that token or fold it into the above? Or, write a better construct entirely that eliminates the need for it?

  Read the article

• How do I mock a method with an open array parameter in PascalMock?

  - by Oliver Giesen

  I'm currently in the process of getting started with unit testing and mocking for good and I stumbled over the following method that I can't seem to fabricate a working mock implementation for: function GetInstance(const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID = CID_DEFAULT): Boolean; (TImplContextID is just an alias for Integer) I thought it would have to look something like this: function TImplementationProviderMock.GetInstance( const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID): Boolean; begin Result := AddCall('GetInstance') .WithParams([@AIID, AContextID]) .ReturnsOutParams([AInstance]) .ReturnValue; end; But the compiler complains about the .ReturnsOutParams([AInstance]) saying "Bad argument type in variable type array constructor.". Also I haven't found a way to specify the open array parameter AArgs at all. Also, is using the @-notation for the TGUID-typed parameter the right way to go? Is it possible to mock this method with the current version of PascalMock at all? Update: I now realize I got the purpose of ReturnsOutParams completely wrong: It's intended to be used for populating the values to be returned when defining the expectations rather than for mocking the call itself. I now think the correct syntax for mocking the out parameter would probably have to look more like this: function TImplementationProviderMock.GetInstance( const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID): Boolean; var lCall: TMockMethod; begin lCall := AddCall('GetInstance').WithParams([@AIID, AContextID]); Pointer(AInstance) := lCall.OutParams[0]; Result := lCall.ReturnValue; end; The questions that remain are how to mock the open array parameter AArgs and whether passing the TGUID argument (i.e. a value type) by address will work out...

  Read the article

• Indexing and Searching Over Word Level Annotation Layers in Lucene

  - by dmcer

  I have a data set with multiple layers of annotation over the underlying text, such as part-of-tags, chunks from a shallow parser, name entities, and others from various natural language processing (NLP) tools. For a sentence like The man went to the store, the annotations might look like: Word POS Chunk NER ==== === ===== ======== The DT NP Person man NN NP Person went VBD VP - to TO PP - the DT NP Location store NN NP Location I'd like to index a bunch of documents with annotations like these using Lucene and then perform searches across the different layers. An example of a simple query would be to retrieve all documents where Washington is tagged as a person. While I'm not absolutely committed to the notation, syntactically end-users might enter the query as follows: Query: Word=Washington,NER=Person I'd also like to do more complex queries involving the sequential order of annotations across different layers, e.g. find all the documents where there's a word tagged person followed by the words arrived at followed by a word tagged location. Such a query might look like: Query: "NER=Person Word=arrived Word=at NER=Location" What's a good way to go about approaching this with Lucene? Is there anyway to index and search over document fields that contain structured tokens?

  Read the article

• why libxml2 quotes starting double slash in CDATA with javascript

  - by Vincenzo

  This is my code: <?php $data = <<<EOL <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html> <script type="text/javascript"> //<![CDATA[ var a = 123; // JS code //]]> </script> </html> EOL; $dom = new DOMDocument(); $dom->preserveWhiteSpace = false; $dom->formatOutput = false; $dom->loadXml($data); echo '<pre>' . htmlspecialchars($dom->saveXML()) . '</pre>'; This is result: <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <script type="text/javascript"><![CDATA[ //]]><![CDATA[ var a = 123; // JS code //]]><![CDATA[ ]]></script></html> If and when I remove the DOCTYPE notation from XML document, CDATA works properly and leading/trailing double slash is not turned into CDATA. What is the problem here? Bug in libxml2? PHP version is 5.2.13 on Linux. Thanks.

  Read the article

• NHibernate query against the key field of a dictionary (map)

  - by Carl Raymond

  I have an object model where a Calendar object has an IDictionary<MembershipUser, Perms> called UserPermissions, where MembershipUser is an object, and Perms is a simple enumeration. This is in the mapping file for Calendar as <map name="UserPermissions" table="CalendarUserPermissions" lazy="true" cascade="all"> <key column="CalendarID"/> <index-many-to-many class="MembershipUser" column="UserGUID" /> <element column="Permissions" type="CalendarPermission" not-null="true" /> </map> Now I want to execute a query to find all calendars for which a given user has some permission defined. The permission is irrelevant; I just want a list of the calendars where a given user is present as a key in the UserPermissions dictionary. I have the username property, not a MembershipUser object. How do I build that using QBC (or HQL)? Here's what I've tried: ISession session = SessionManager.CurrentSession; ICriteria calCrit = session.CreateCriteria<Calendar>(); ICriteria userCrit = calCrit.CreateCriteria("UserPermissions.indices"); userCrit.Add(Expression.Eq("Username", username)); return calCrit.List<Calendar>(); This constructed invalid SQL -- the WHERE clause contained WHERE membership1_.Username = @p0 as expected, but the FROM clause didn't include the MemberhipUsers table. Also, I really had to struggle to learn about the .indices notation. I found it by digging through the NHibernate source code, and saw that there's also .elements and some other dotted notations. Where's a reference to the allowed syntax of an association path? I feel like what's above is very close, and just missing something simple.

  Read the article

• Python: Created nested dictionary from list of paths

  - by sberry2A

  I have a list of tuples the looks similar to this (simplified here, there are over 14,000 of these tuples with more complicated paths than Obj.part) [ (Obj1.part1, {<SPEC>}), (Obj1.partN, {<SPEC>}), (ObjK.partN, {<SPEC>}) ] Where Obj goes from 1 - 1000, part from 0 - 2000. These "keys" all have a dictionary of specs associated with them which act as a lookup reference for inspecting another binary file. The specs dict contains information such as the bit offset, bit size, and C type of the data pointed to by the path ObjK.partN. For example: Obj4.part500 might have this spec, {'size':32, 'offset':128, 'type':'int'} which would let me know that to access Obj4.part500 in the binary file I must unpack 32 bits from offset 128. So, now I want to take my list of strings and create a nested dictionary which in the simplified case will look like this data = { 'Obj1' : {'part1':{spec}, 'partN':{spec} }, 'ObjK' : {'part1':{spec}, 'partN':{spec} } } To do this I am currently doing two things, 1. I am using a dotdict class to be able to use dot notation for dictionary get / set. That class looks like this: class dotdict(dict): def __getattr__(self, attr): return self.get(attr, None) __setattr__ = dict.__setitem__ __delattr__ = dict.__delitem__ The method for creating the nested "dotdict"s looks like this: def addPath(self, spec, parts, base): if len(parts) > 1: item = base.setdefault(parts[0], dotdict()) self.addPath(spec, parts[1:], item) else: item = base.setdefault(parts[0], spec) return base Then I just do something like: for path, spec in paths: self.lookup = dotdict() self.addPath(spec, path.split("."), self.lookup) So, in the end self.lookup.Obj4.part500 points to the spec. Is there a better (more pythonic) way to do this?

  Read the article

• Nullability (Regular Expressions)

  - by danportin

  In Brzozowski's "Derivatives of Regular Expressions" and elsewhere, the function d(R) returning ? if a R is nullable, and Ø otherwise, includes clauses such as the following: d(R1 + R2) = d(R1) + d(R2) d(R1 · R2) = d(R1) ? d(R2) Clearly, if both R1 and R2 are nullable then (R1 · R2) is nullable, and if either R1 or R2 is nullable then (R1 + R2) is nullable. It is unclear to me what the above clauses are supposed to mean, however. My first thought, mapping (+), (·), or the Boolean operations to regular sets is nonsensical, since in the base case, d(a) = Ø (for all a ? S) d(?) = ? d(Ø) = Ø and ? is not a set (nor is the return type of d, which is a regular expression). Furthermore, this mapping isn't indicated, and there is a separate notation for it. I understand nullability, but I'm lost on the definition of the sum, product, and Boolean operations in the definition of d: how are ? or Ø returned from d(R1) ? d(R2), for instance, in the definition off d(R1 · R2)?

  Read the article

• How to make a calculator in PHP?

  - by Giulio Muscarello

  I want to use PHP to calculate simple algebraic expressions like, 8*(5+1), entered via an <input> tag by a normal user (which means, normal notation: no syntax changes like Multiply(8, Add(5, 1))). Also, it has to show all steps, but that's not hard. The problem, right now, is calculating the value of the expressions. Note: this is what I thought so far, which is quite inefficient but it's a provisory solution. Just replace strings where possible: in our example, recognize the string 5+1 and replace it with 6. Then, loop again, replace (6) with 6, loop again, and replace 8*6 with 48. The code for multiplying, for example, should look like this: for ($a=1; $a < 1000; $a++) { for ($b=1; $b < 1000; $b++) { string_replace($a . '*' . $b, $a*$b, $string); } }

  Read the article

• Appropriate uses of Monad `fail` vs. MonadPlus `mzero`

  - by jberryman

  This is a question that has come up several times for me in the design code, especially libraries. There seems to be some interest in it so I thought it might make a good community wiki. The fail method in Monad is considered by some to be a wart; a somewhat arbitrary addition to the class that does not come from the original category theory. But of course in the current state of things, many Monad types have logical and useful fail instances. The MonadPlus class is a sub-class of Monad that provides an mzero method which logically encapsulates the idea of failure in a monad. So a library designer who wants to write some monadic code that does some sort of failure handling can choose to make his code use the fail method in Monad or restrict his code to the MonadPlus class, just so that he can feel good about using mzero, even though he doesn't care about the monoidal combining mplus operation at all. Some discussions on this subject are in this wiki page about proposals to reform the MonadPlus class. So I guess I have one specific question: What monad instances, if any, have a natural fail method, but cannot be instances of MonadPlus because they have no logical implementation for mplus? But I'm mostly interested in a discussion about this subject. Thanks! EDIT: One final thought occured to me. I recently learned (even though it's right there in the docs for fail) that monadic "do" notation is desugared in such a way that pattern match failures, as in (x:xs) <- return [] call the monad's fail. It seems like the language designers must have been strongly influenced by the prospect of some automatic failure handling built in to haskell's syntax in their inclusion of fail in Monad.

  Read the article

• Should I pass a SqlDataReader by reference or not when passing it out to multiple threads.

  - by deroby

  Hi all, being new to c# I've run into this 'conundrum' when passing around a SqlDataReader between different threads. Without going into too much detail, the idea is to have a main thread fetching data from the database (a large recordset) and then have a helper-task run through this record by record and doing some stuff based upon the contents of this. There is no feedback to the recordset, it simply wades through until no records are left. This works fine, but given the nature of the job at hand it should be possible to have this job spread over different threads (CPUs) to maximize throughput (the order of execution is of no significance). The question then becomes, when I pass this recordset in a SqlDataReader, do I have to use ref or not ? It kind of boils down to the question : if I pass the object around without specifying ref, won't it create new copies in memory and have records processed n times ? Or, don't I risk having the record-position being moved forward while not all fields have been fully read yet ? The latter seems more like a 'data racing' issue and probably is covered by the lock()ing mechanism (or not?). My initial take on the problem was that it doesn't really hurt passing the variable using ref, yet as a colleague put it : "you only need ref when you're doing something wrong" =) Additionally using ref restricts me from applying a Using() construction too which isn't very nice either. I thus create a "basic" project that tackles the same approach but without the ref notation. Tests so far show that it works flawlessly on a Core2Duo (2cpu) using any number of threads, yet I'm still a bit wary... What do you experts think about this ? Use ref or not ? You can find the test-project here as it seems I can't upload it to this question directly ?!? ps: it's just a test-project and I'm new to c#, so please be gentle on me when breaking down the code =P

  Read the article

• How do I alias the scala setter method 'myvar_$(myval)' to something more pleasing when in java?

  - by feydr

  I've been converting some code from java to scala lately trying to tech myself the language. Suppose we have this scala class: class Person() { var name:String = "joebob" } Now I want to access it from java so I can't use dot-notation like I would if I was in scala. So I can get my var's contents by issuing: person = Person.new(); System.out.println(person.name()); and set it via: person = Person.new(); person.name_$eq("sallysue"); System.out.println(person.name()); This holds true cause our Person Class looks like this in javap: Compiled from "Person.scala" public class Person extends java.lang.Object implements scala.ScalaObject{ public Person(); public void name_$eq(java.lang.String); public java.lang.String name(); public int $tag() throws java.rmi.RemoteException; } Yes, I could write my own getters/setters but I hate filling classes up with that and it doesn't make a ton of sense considering I already have them -- I just want to alias the _$eq method better. (This actually gets worse when you are dealing with stuff like antlr because then you have to escape it and it ends up looking like person.name_\$eq("newname"); Note: I'd much rather have to put up with this rather than fill my classes with more setter methods. So what would you do in this situation?

  Read the article

• What is the nicest way to parse this in C++ ?

  - by ereOn

  Hi, In my program, I have a list of "server address" in the following format: host[:port] The brackets here, indicate that the port is optional. host can be a hostname, an IPv4 or IPv6 address. port, if present can be a numeric port number or a service string (like: "http" or "ssh"). If port is present and host is an IPv6 address, host must be in "bracket-enclosed" notation (Example: [::1]) Here are some valid examples: localhost localhost:11211 127.0.0.1:http [::1]:11211 ::1 [::1] And an invalid example: ::1:80 // Invalid: Is this the IPv6 address ::1:80 and a default port, or the IPv6 address ::1 and the port 80 ? ::1:http // This is not ambigous, but for simplicity sake, let's consider this is forbidden as well. My goal is to separate such entries in two parts (obviously host and port). I don't care if either the host or port are invalid as long as they don't contain a : (290.234.34.34.5 is ok for host, it will be rejected in the next process); I just want to separate the two parts, or if there is no port part, to know it somehow. I tried to do something with std::stringstream but everything I come up to seems hacky and not really elegant. How would you do this in C++ ? I don't mind answers in C but C++ is prefered. Any boost solution is welcome as well. Thank you.

  Read the article

• How can I solve the Log Pile wooden puzzle with a computer program?

  - by craig1410

  Can anyone suggest how to solve the Log Pile wooden puzzle using a computer program? See here to visualise the puzzle: http://www.puzzlethis.co.uk/products/madcow/the_log_pile.htm The picture only shows some of the pieces. The full set of 10 pieces are configured as follows with 1 representing a peg, -1 representing a hole and 0 representing neither a peg nor a hole. -1,1,0,-1,0 1,0,1,0,0 1,-1,1,0,0 -1,-1,0,0,-1 -1,1,0,1,0 0,1,0,0,1 1,0,-1,0,-1 0,-1,0,1,0 0,0,-1,1,-1 1,0,-1,0,0 The pieces can be interlocked in two layers of 5 pieces each with the top layer at 90 degrees to the bottom layer as shown in the above link. I have already created a solution to this problem myself using Java but I feel that it was a clumsy solution and I am interested to see some more sophisticated solutions. Feel free to either suggest a general approach or to provide a working program in the language of your choice. My approach was to use the numeric notation above to create an array of "Logs". I then used a combination/permutation generator to try all possible arrangements of the Logs until a solution was found where all the intersections equated to zero (ie. Peg to Hole, Hole to Peg or Blank to Blank). I used some speed-ups to detect the first failed intersection for a given permutation and move on to the next permutation. I hope you find this as interesting as I have. Thanks, Craig.

  Read the article

• How do I alias the scala setter method 'myvar_$eq(myval)' to something more pleasing when in java?

  - by feydr

  I've been converting some code from java to scala lately trying to teach myself the language. Suppose we have this scala class: class Person() { var name:String = "joebob" } Now I want to access it from java so I can't use dot-notation like I would if I was in scala. So I can get my var's contents by issuing: person = Person.new(); System.out.println(person.name()); and set it via: person = Person.new(); person.name_$eq("sallysue"); System.out.println(person.name()); This holds true cause our Person Class looks like this in javap: Compiled from "Person.scala" public class Person extends java.lang.Object implements scala.ScalaObject{ public Person(); public void name_$eq(java.lang.String); public java.lang.String name(); public int $tag() throws java.rmi.RemoteException; } Yes, I could write my own getters/setters but I hate filling classes up with that and it doesn't make a ton of sense considering I already have them -- I just want to alias the _$eq method better. (This actually gets worse when you are dealing with stuff like antlr because then you have to escape it and it ends up looking like person.name_\$eq("newname"); Note: I'd much rather have to put up with this rather than fill my classes with more setter methods. So what would you do in this situation?

  Read the article

• Extended slice that goes to beginning of sequence with negative stride

  - by recursive

  Bear with me while I explain my question. Skip down to the bold heading if you already understand extended slice list indexing. In python, you can index lists using slice notation. Here's an example: >>> A = list(range(10)) >>> A[0:5] [0, 1, 2, 3, 4] You can also include a stride, which acts like a "step": >>> A[0:5:2] [0, 2, 4] The stride is also allowed to be negative, meaning the elements are retrieved in reverse order: >>> A[5:0:-1] [5, 4, 3, 2, 1] But wait! I wanted to see [4, 3, 2, 1, 0]. Oh, I see, I need to decrement the start and end indices: >>> A[4:-1:-1] [] What happened? It's interpreting -1 as being at the end of the array, not the beginning. I know you can achieve this as follows: >>> A[4::-1] [4, 3, 2, 1, 0] But you can't use this in all cases. For example, in a method that's been passed indices. My question is: Is there any good pythonic way of using extended slices with negative strides and explicit start and end indices that include the first element of a sequence? This is what I've come up with so far, but it seems unsatisfying. >>> A[0:5][::-1] [4, 3, 2, 1, 0]

  Read the article

• Pre-done SQLs to be converted to Rails' style moduls

  - by Hoornet

  I am a Rails newbie and would really appreciate if someone converted these SQLs to complete modules for rails. I know its a lot to ask but I can't just use find_by_sql for all of them. Or can I? These are the SQLs (they run on MS-SQL): 1) SELECT STANJA_NA_DAN_POSTAVKA.STA_ID, STP_DATE, STP_TIME, STA_OPIS, STA_SIFRA, STA_POND FROM STANJA_NA_DAN_POSTAVKA INNER JOIN STANJA_NA_DAN ON(STANJA_NA_DAN.STA_ID=STANJA_NA_DAN_POSTAVKA.STA_ID) WHERE ((OSE_ID=10)AND (STANJA_NA_DAN_POSTAVKA.STP_DATE={d '2010-03-30'}) AND (STANJA_NA_DAN_POSTAVKA.STP_DATE<={d '2010-03-30'})) 2) SELECT ZIGI_OBDELANI.OSE_ID, ZIGI_OBDELANI.DOG_ID AS DOG_ID, ZIGI_OBDELANI.ZIO_DATUM AS DATUM, ZIGI_PRICETEK.ZIG_TIME_D AS ZIG_PRICETEK, ZIGI_KONEC.ZIG_TIME_D AS ZIG_KONEC FROM (ZIGI_OBDELANI INNER JOIN ZIGI ZIGI_PRICETEK ON ZIGI_OBDELANI.ZIG_ID_PRICETEK = ZIGI_PRICETEK.ZIG_ID) INNER JOIN ZIGI ZIGI_KONEC ON ZIGI_OBDELANI.ZIG_ID_KONEC = ZIGI_KONEC.ZIG_ID WHERE (ZIGI_OBDELANI.OSE_ID = 10) AND (ZIGI_OBDELANI.ZIO_DATUM = {d '2010-03-30'}) AND (ZIGI_OBDELANI.ZIO_DATUM <= {d '2010-03-30'}) AND (ZIGI_PRICETEK.ZIG_VELJAVEN < 0) AND (ZIGI_KONEC.ZIG_VELJAVEN < 0) ORDER BY ZIGI_OBDELANI.OSE_ID, ZIGI_PRICETEK.ZIG_TIME ASC 3) SELECT STA_ID, SUM(STP_TIME) AS SUM_STP_TIME, COUNT(STA_ID) FROM STANJA_NA_DAN_POSTAVKA WHERE ((STP_DATE={d '2010-03-30'}) AND (STP_DATE<={d '2010-03-30'}) AND (STA_ID=3) AND (OSE_ID=10)) GROUP BY STA_ID 4) SELECT DATUM, TDN_ID, TDN_OPIS, URN_OPIS, MOZNI_PROBLEMI, PRIHOD, ODHOD, OBVEZNOST, ZAKLJUCEVANJE_DATUM FROM OBRACUNAJ_DAN WHERE ((OSE_ID=10) AND (DATUM={d '2010-02-28'}) AND (DATUM<={d '2010-03-30'})) ORDER BY DATUM These SQLs are daily working hours and I got them as is. Also I got Database with it which (as you can see from the SQL-s) is not in Rails conventions. As a P.S.: 1)Things like STP_DATE={d '2010-03-30'}) are of course dates (in Slovenian date notation) and will be replaced with a variable (date), so that the user could choose date from and date to. 2) All of this data will be shown in the same page in the table,so maybe all in one module? Or many?; if this helps, maybe. So can someone help me? Its for my work and its my 1st project and I am a Rails newbie and the bosses are getting inpatient(they are getting quite loud actually) Thank you very very much!

  Read the article

• "for" loop from program 7.6 from Kochan's "Programming in Objective-C"

  - by Mr_Vlasov

  "The sigma notation is shorthand for a summation. Its use here means to add the values of 1/2^i, where i varies from 1 to n. That is, add 1/2 + 1/4 + 1/8 .... If you make the value of n large enough, the sum of this series should approach 1. Let’s experiment with different values for n to see how close we get." #import "Fraction.h" int main (int argc, char *argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; Fraction *aFraction = [[Fraction alloc] init]; Fraction *sum = [[Fraction alloc] init], *sum2; int i, n, pow2; [sum setTo: 0 over: 1]; // set 1st fraction to 0 NSLog (@"Enter your value for n:"); scanf ("%i", &n); pow2 = 2; for (i = 1; i <= n; ++i) { [aFraction setTo: 1 over: pow2]; sum2 = [sum add: aFraction]; [sum release]; // release previous sum sum = sum2; pow2 *= 2; } NSLog (@"After %i iterations, the sum is %g", n, [sum convertToNum]); [aFraction release]; [sum release]; [pool drain]; return 0; } Question: Why do we have to create additional variable sum2 that we are using in the "for" loop? Why do we need "release previous sum" here and then again give it a value that we just released? : sum2 = [sum add: aFraction]; [sum release]; // release previous sum sum = sum2; Is it just for the sake of avoiding memory leakage? (method "add" initializes a variable that is stored in sum2)

  Read the article

< Previous Page | 14 15 16 17 18 19 20 21 22 23  | Next Page >