Search Results

Search found 13000 results on 520 pages for 'member functions'.

Page 341/520 | < Previous Page | 337 338 339 340 341 342 343 344 345 346 347 348  | Next Page >

• Mathematica Plot3D does not produce a plot when graphing a user-defined function?

  - by pythonscript

  I'm writing a simple Mathematica implementation of the black-scholes model and using Plot3D to plot the pricing surface. However, when I run this code, no plot is produced. My call and put functions to produce correct values when run separately, but no plot is produced. Code: Clear[d1, d2, call, put, stockPrice, strikePrice, riskFreeRate, timeToExp, volatility] d1[stockPrice_, strikePrice_, riskFreeRate_, timeToExp_, volatility_] := (Log[stockPrice / strikePrice] + (riskFreeRate + 0.5*volatility^2)*timeToExp) / (volatility * Sqrt[timeToExp]) d2[stockPrice_, strikePrice_, riskFreeRate_, timeToExp_, volatility_] := d1[stockPrice, strikePrice, riskFreeRate, timeToExp, volatility] - volatility*Sqrt[timeToExp] call[stockPrice_, strikePrice_, riskFreeRate_, timeToExp_, volatility_] := stockPrice * CDF[NormalDistribution[0, 1], d1[stockPrice, strikePrice, riskFreeRate, timeToExp, volatility]] - strikePrice * Exp[-riskFreeRate*timeToExp] *CDF[NormalDistribution[0, 1], d2[stockPrice, strikePrice, riskFreeRate, timeToExp, volatility]] Plot3D[call[stockPrice, 500, 0.0030, timeToExp, 0.39], {stockPrice, 10, 1000}, {timetoExp, 0.0833333, 5}] Other plots, like this sample from the reference, do work. Plot3D[{x^2 + y^2, -x^2 - y^2}, {x, -2, 2}, {y, -2, 2}, RegionFunction -> Function[{x, y, z}, x^2 + y^2 <= 4], BoxRatios -> Automatic]

  Read the article

• Does SQLite handle non-English locales out of the box?

  - by Andrey Tarantsov

  I have noticed that Google Toolbox for Mac replaces several SQLite built-in functions (LOWER/UPPER, LIKE, GLOB) with its own versions that handle string locales better. So, question to everyone who has SQLite experience: have you ever had any problems with non-English locales in SQLite? Does one really have to do something to properly handle non-English alphabets? What kinds of problems are expected if I use SQLite APIs as-is? (I'm going to use SQLite on the iPhone, but I guess it's the same across all platforms. I've been using Core Data previously and never had any problems, but this time I want to switch to non-ORMed db access.)

  Read the article

• Implementing password hashing/salting algorithm from crackstation.net

  - by Mason240

  I am trying to implement a password hashing/salting algorithm from crackstation.net, but I am unsure how implement it. Storing the password upon user registration seems to be as simple as passing the password into create_hash(). $password = create_hash($_POST['Password']; I'm not following how to validate upon user login. validate_password($password, $good_hash) returns either true or false, and takes $password as parameter, so it seems like a no brainer except for the second parameter $good_hash. Where does this param come from? It is my understanding that password is turned into a hash value every time its used, and that the hash value is what is stored and compared. So why would I have both the $password and $good_hash values? Quick overview of the functions: function create_hash($password){ calls pbkdf2() } function validate_password($password, $good_hash){ calls pbkdf2() calls slow_equals() } function slow_equals($a, $b){ } function pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output = false){ } Of course a different, better method for this would also be just as helpful. Thank you

  Read the article

• Java constructor and modify the object properties at runtime

  - by lupin

  Note: This is an assignment Hi, I have the following class/constructor. import java.io.*; class Set { public int numberOfElements = 0; public String[] setElements = new String[5]; public int maxNumberOfElements = 5; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { int numberOfElements = numberOfE; String[] setElements = new String[setE]; int maxNumberOfElements = maxNumberOfE; } // Helper method to shorten/remove element of array since we're using basic array instead of ArrayList or HashSet from collection interface :( static String[] removeAt(int k, String[] arr) { final int L = arr.length; String[] ret = new String[L - 1]; System.arraycopy(arr, 0, ret, 0, k); System.arraycopy(arr, k + 1, ret, k, L - k - 1); return ret; } int findElement(String element) { int retval = 0; for ( int i = 0; i < setElements.length; i++) { if ( setElements[i] != null && setElements[i].equals(element) ) { return retval = i; } retval = -1; } return retval; } void add(String newValue) { int elem = findElement(newValue); if( numberOfElements < maxNumberOfElements && elem == -1 ) { setElements[numberOfElements] = newValue; numberOfElements++; } } int getLength() { if ( setElements != null ) { return setElements.length; } else { return 0; } } String[] emptySet() { setElements = new String[0]; return setElements; } Boolean isFull() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == maxNumberOfElements ){ return True; } else { return False; } } Boolean isEmpty() { Boolean True = new Boolean(true); Boolean False = new Boolean(false); if ( setElements.length == 0 ) { return True; } else { return False; } } void remove(String newValue) { for ( int i = 0; i < setElements.length; i++) { if ( setElements[i].equals(newValue) ) { setElements = removeAt(i,setElements); } } } int isAMember(String element) { int retval = -1; for ( int i = 0; i < setElements.length; i++ ) { if (setElements[i] != null && setElements[i].equals(element)) { return retval = i; } } return retval; } void printSet() { for ( int i = 0; i < setElements.length; i++) { System.out.println("Member elements on index: "+ i +" " + setElements[i]); } } String[] getMember() { String[] tempArray = new String[setElements.length]; for ( int i = 0; i < setElements.length; i++) { if(setElements[i] != null) { tempArray[i] = setElements[i]; } } return tempArray; } Set union(Set x, Set y) { String[] newXtemparray = new String[x.getLength()]; String[] newYtemparray = new String[y.getLength()]; Set temp = new Set(1,20,20); newXtemparray = x.getMember(); newYtemparray = x.getMember(); for(int i = 0; i < newXtemparray.length; i++) { temp.add(newYtemparray[i]); } for(int j = 0; j < newYtemparray.length; j++) { temp.add(newYtemparray[j]); } return temp; } } // This is the SetDemo class that will make use of our Set class class SetDemo { public static void main(String[] args) { //get input from keyboard BufferedReader keyboard; InputStreamReader reader; String temp = ""; reader = new InputStreamReader(System.in); keyboard = new BufferedReader(reader); try { System.out.println("Enter string element to be added" ); temp = keyboard.readLine( ); System.out.println("You entered " + temp ); } catch (IOException IOerr) { System.out.println("There was an error during input"); } /* ************************************************************************** * Test cases for our new created Set class. * ************************************************************************** */ Set setA = new Set(1,10,10); setA.add(temp); setA.add("b"); setA.add("b"); setA.add("hello"); setA.add("world"); setA.add("six"); setA.add("seven"); setA.add("b"); int size = setA.getLength(); System.out.println("Set size is: " + size ); Boolean isempty = setA.isEmpty(); System.out.println("Set is empty? " + isempty ); int ismember = setA.isAMember("sixb"); System.out.println("Element six is member of setA? " + ismember ); Boolean output = setA.isFull(); System.out.println("Set is full? " + output ); setA.printSet(); int index = setA.findElement("world"); System.out.println("Element b located on index: " + index ); setA.remove("b"); setA.emptySet(); int resize = setA.getLength(); System.out.println("Set size is: " + resize ); setA.printSet(); Set setB = new Set(0,10,10); Set SetA = setA.union(setB,setA); SetA.printSet(); } } I have two question here, why I when I change the class property declaration to: class Set { public int numberOfElements; public String[] setElements; public int maxNumberOfElements; // constructor for our Set class public Set(int numberOfE, int setE, int maxNumberOfE) { int numberOfElements = numberOfE; String[] setElements = new String[setE]; int maxNumberOfElements = maxNumberOfE; } I got this error: \ javaprojects>java SetDemo Enter string element to be added a You entered a Exception in thread "main" java.lang.NullPointerException at Set.findElement(Set.java:30) at Set.add(Set.java:43) at SetDemo.main(Set.java:169) Second, on the union method, why the result of SetA.printSet still printing null, isn't it getting back the return value from union method? Thanks in advance for any explaination. lupin

  Read the article

• How do I mock memory allocation failures ?

  - by Andrei Ciobanu

  I want to extensively test some pieces of C code for memory leaks. On my machine I have 4 Gb of RAM, so it's very unlikely for a dynamic memory allocation to fail. Still I want to see the comportment of the code if memory allocation fails, and see if the recover mechanism is "strong" enough. What do you suggest ? How do I emulate an environment with lower memory specs ? How do i mock my tests ? EDIT: I want my tests to be code independent. I only have "access" to return values for different functions in the library I am testing. I am not supposed to write "test logic" inside the code I am testing.

  Read the article

• Implements an Undo/Redo in MVC

  - by bnabilos

  Hello, I have a Java application and I want to implement an Undo/Redo option. the value that I want to stock and that I want to be able to recover is an integer. My Class Model implements the interface StateEditable and I have to redefine the 2 functions restoreState(Hashtable<?, ?> state) and storeState(Hashtable<Object, Object> state) but I don't know what to put on them. It will be really great if somebody can help me to do that. These are the first lines of my Model class, the value that I want to do an undo/redo on it is value public class Model extends Observable implements StateEditable { private int value = 5; private UndoManager undoRedo = new UndoManager(); final UndoableEditListener editListener = new UndoableEditListener() { public void undoableEditHappened(UndoableEditEvent evt) { undoRedo.addEdit(evt.getEdit()); } }; @Override public void restoreState(Hashtable<?, ?> state) { } @Override public void storeState(Hashtable<Object, Object> state) { } }

  Read the article

• JQuery never reaches success or fail on aspx returning json.

  - by David

  Basicaly I have my aspx page doing <% Response.Clear(); Response.Write("{\"Success\": \"true\" }"); Response.End(); %> My JQuery code is function DoSubmit(r) { if (r == null || r.length == 0 || formdata == null || formdata.length == 0) return; for (i = 0; i < formdata.length; i++) { var fd = formdata[i]; r[fd.Name] = fd.Value; } r["ModSeq"] = tblDef.ModSeq; jQuery.ajax({ url: "NashcoUpdate.aspx" , succsess: doRow , error: DoSubmitError , complete: DoSubmitComplete , dataType: "json" , cache: false , data: r , type: "post" }) } When I call the DoSubmit() function every thing works but the doRow or DoSubmitError functions never get called only the DoSubmitComplete function. When I look at the response text in teh DoSubmitComple function it is {"Success": "true" } Every JSON tester I have tried says that this is valied JSON. What am I doing wrong here?

  Read the article

• Jquery Widget Performance

  - by jamie-wilson

  I am working on an interface which involves ALOT of javascript. There is a calendar and blocks drawn on the calendar. The calendar is a jQuery widget, which works beautifully. The blocks drawn on top are also jQuery widgets. While it works - I am wondering, every time I create another block, is the widget fully duplicating, or is it referencing the widget? If I end up with 200 blocks on the screen, do I have 200 copies of the widget? Because if so i'm sure this will impact the performance quite heavily. Also it would determine whether I have functions inside the widget, or have them external to the widget looking in if that makes sense. Just putting some feelers out there for thoughts. I couldn't find anything by searching online.

  Read the article

• Getting a sorted distinct list from mySQL

  - by Stomped

  Goal I'l like to get a list of unique FID's ordered by the the one which has most recently been changed. In this sample table it should return FIDs in the order of 150, 194, 122 Example Data ID FID changeDate ---------------------------------------------- 1 194 2010-04-01 2 122 2010-04-02 3 194 2010-04-03 4 150 2010-04-04 My Attempt I thought distinct and order by would do the trick. I initially tried: SELECT distinct `FID` FROM `tblHistory` WHERE 1 ORDER BY changeDate desc # Returns 150, 122, 194 using GROUP BY has the same result. I'm just barely a SQL amateur, and I'm a bit hung up. What seems to be happening is the aggregating functions find the first occurrence of each and then perform the sort. Is there a way I can get the result I want straight from mySQL or do I have to grab all the data and then sort it in the PHP?

  Read the article

• MVC Implementation PHP Zend PDF generation

  - by zod

  Am using Zend framework and PHP Am going to generate a PDF using Zend . So the View is PDF.There is no PHTML. But if i dont use PHTML in view , is it a perfect MVC? if i want to be a perfect MVC shall i do the db retrieval and variable declaration and assigning in controller and use view and use all pdf functions in view phtml file will it make a perfect MVC? What is the advantage of MVC in this case? :-) can i do the include of zend pdf in phtml file or controller php file? what is the difference ?

  Read the article

• Calling a function of en external javascript file

  - by strakastroukas

  Hello. In general... How can I make a call on a function of an external javascript file? More specific... In the head tag i have <script type="text/javascript" src="JScript/FontSize.js"></script> The external javascript file, (that i would like to call) FontSize.js contains the following functions. function checkCookie() function setCookie(c_name, value, expiredays) function getCookie(c_name) function increaseFontSize() function decreaseFontSize() The FontSize.js is located at the ~/Jscript/ directory I guess the body on load should contain something like <body onload="/JScript/Fontsize.js/checkCookie()"> Of course nothing works as it should because, i do not know how to make the call to a function to an external js file

  Read the article

• Cross platform unicode path handling

  - by Matt Joiner

  I'm using boost::filesystem for cross-platform path manipulation, but this breaks down when calls need to be made down into interfaces I don't control that won't accept UTF-8. For example when using the Windows API, I need to convert to UTF-16, and then call the wide-string version of whatever function I was about to call, and then convert any output back to UTF-8. While the wpath, and other w* forms of many of the boost::filesystem functions help keep sanity, are there any suggestions for how best to handle this conversion to wide-string forms where needed, while maintaining consistency in my own code?

  Read the article

• Delphi Compiler Directive to Evaluate Arguments in Reverse

  - by Peter Turner

  I was really impressed with this delphi two liner using the IFThen function from Math.pas. However, it evaluates the DB.ReturnFieldI first, which is unfortunate because I need to call DB.first to get the first record. DB.RunQuery('select awesomedata1 from awesometable where awesometableid = "great"'); result := IfThen(DB.First = 0, DB.ReturnFieldI('awesomedata1')); Obviously this isn't such a big deal, as I could make it work with five robust liners. But all I need for this to work is for Delphi to evaluate DB.first first and DB.ReturnFieldI second. I don't want to change math.pas and I don't think this warrants me making a overloaded ifthen because there's like 16 ifthen functions. Just let me know what the compiler directive is, if there is an even better way to do this, or if there is no way to do this and anyone whose procedure is to call db.first and blindly retrieve the first thing he finds is not a real programmer.

  Read the article

• Dynamic Windows Forms Components (Performance problem)

  - by Svisstack

  I have a problem with performance of my code under Windows Forms. Have a form, her layout is depending on constructor data, because he layout must be OnLoad or in Constructor generated. I generation is simple, base FlowLayoutPanel have other FlowLayoutPanels, for each have a Label and TextBox with DataBinding. Problem is this is VERY SLOW, up to 20 seconds, i drawing less than 100 controls, from Performace Session i know a problem is on 70% procesing functions: System.Windows.Forms.Control.ControlCollection.Add(class System.Windows.Forms.Control) System.Windows.Forms.ControlBindingsCollection.Add(class System.Windows.Forms.Binding) How i can do with this? Anyone help me in this problem? How solve the dynamic form layout problem?

  Read the article

• How Do I Convert text to a WAV file With Inaudible Waveform?

  - by Scott

  I am trying to create an audio watermarking system. I figure the best solution is to create an audio file (WAV) based on a unique string of text and then combine this with the original wav. The part that makes this tricky (for me anyway) is: How do I convert the text string to a wav? How do I ensure that the resulting WAV form is inaudible (or at least barely noticeable to the listener). I would prefer this be done server side (via PHP, etc) but if the processing load isn't too much then would be ok with something in Flash or Javascript. I'd be willing to pay someone to create me a workable solution (complete source code that functions as described). Thanks, Scott!

  Read the article

• friendship and operator overloading help

  - by sil3nt

  hello there, I have the following class #ifndef Container_H #define Container_H #include <iostream> using namespace std; class Container{ friend bool operator==(const Container &rhs,const Container &lhs); public: void display(ostream & out) const; private: int sizeC; // size of Container int capacityC; // capacity of dynamic array int * elements; // pntr to dynamic array }; ostream & operator<< (ostream & out, const Container & aCont); #endif and this source file #include "container.h" /*----------------------------********************************************* note: to test whether capacityC and sizeC are equal, must i add 1 to sizeC? seeing as sizeC starts off with 0?? */ Container::Container(int maxCapacity){ capacityC = maxCapacity; elements = new int [capacityC]; sizeC = 0; } Container::~Container(){ delete [] elements; } Container::Container(const Container & origCont){ //copy constructor? int i = 0; for (i = 0; i<capacityC; i++){ //capacity to be used here? (*this).elements[i] = origCont.elements[i]; } } bool Container::empty() const{ if (sizeC == 0){ return true; }else{ return false; } } void Container::insert(int item, int index){ if ( sizeC == capacityC ){ cout << "\n*** Next: Bye!\n"; return; // ? have return here? } if ( (index >= 0) && (index <= capacityC) ){ elements[index] = item; sizeC++; } if ( (index < 0) && (index > capacityC) ){ cout<<"*** Illegal location to insert--"<< index << ". Container unchanged. ***\n"; }//error here not valid? according to original a3? have i implemented wrong? } void Container::erase(int index){ if ( (index >= 0) && (index <= capacityC) ){ //correct here? legal location? int i = 0; while (i<capacityC){ //correct? elements[index] = elements[index+1]; //check if index increases here. i++; } sizeC=sizeC-1; //correct? updated sizeC? }else{ cout<<"*** Illegal location to be removed--"<< index << ". Container unchanged. ***\n"; } } int Container::size()const{ return sizeC; //correct? } /* bool Container::operator==(const Container &rhs,const Container &lhs){ int equal = 0, i = 0; for (i = 0; i < capacityC ; i++){ if ( rhs.elements[i] == lhs.elements[i] ){ equal++; } } if (equal == sizeC){ return true; }else{ return false; } } ostream & operator<< (ostream & out, const Container & aCont){ int i = 0; for (i = 0; i<sizeC; i++){ out<< aCont.elements[i] << " " << endl; } } */ I dont have the other functions in the header file (just a quikie). Anyways, the last two functions in "/* */" I cant get to work, what am I doing wrong here? the first function is to see whether the two arrays are equal to one another

  Read the article

• .NET library for generating javascript?

  - by Rune

  Do you know of a .NET library for generating javascript code? I want to generate javascript code based on information in my .NET application. I would like to be able to create an AST-like datastructure (using C#) and have it turned into valid javascript. I need to be able to create functions, statements, expressions etc., so I need something more than a JSON serializer - but I guess you could think of this as a (very) generalized JSON serializer. Do such libraries exist and if so, could you recommend any? Thank you.

  Read the article

• recommendations for rich scalable internet application

  - by Wouter Roux

  I am planning to develop a web application that must perform the following actions: User authentication allow authenticated user to download data from USB device (roughly 5 meg data) upload the data from the USB device to processing server process the data and display the results to the user further requirements/restrictions: the USB driver supports windows (2000, XP, Vista, 7) the application must support IE, Firefox and Chrome the USB driver must be installed when pointing to the web application the first time the USB driver exposes functionality through exported functions in dll scalability and eye candy is important server details: Windows Server 2008 Enterprise x64, IIS 7.0, SQL server 2008 With the limited details specified: What technology would you recommend? (eg silverlight/asp.net mvc/wcf). What practices/patterns/3rd party controls would you recommend?

  Read the article

• lwjgl 101: How can I write applets?

  - by Vuntic

  I have a working app in lwjgl. It doesn't do much yet; I've just started, but it does compile and run like it's supposed to. I want to make it into an applet. I've followed the guide here, and I have an applet that runs nicely and displays text and such in the applet area and can access the functions of lwjgl (like Sys.alert), but I can't figure out how to get opengl to actually render. I've tried extending an AWTGLCanvas and calling this.add(myAWTGLCanvas), where this is the Applet that I'm using, but... nothing. The initGL() and paintGL() methods never get called. I wonder if I'm supposed to be doing something with Display, but that's not for applets, right? Help? Also: This counts as a "beginner" question, right? Edit: Here's a simplified version of what I have.

  Read the article

• Clipping the caret in a C# program

  - by Bob Sammers

  I'm creating a WinForms control in C# (using VS2008, .net 3.5) which allows text input. I've imported the necessary Win32 API functions from User32.dll for displaying the normal Windows caret and these are all working fine, but it's not displaying exactly how I'd like it. Text is displayed on the control with a blank border and I use Graphics.SetClip() to leave this margin clear. I want the caret to be clipped to the same region, but since I don't paint it and there's no obvious API function to set a clipping region, I can't see any way of doing this. Have I missed anything obvious? The caret is clipped inside the control in which it is drawn. I'm therefore aware that one solution could be to place the text in a separate sub-control with no border. However, if there's a simpler way than redesigning this part of the control, I'd like to look for that first. Thanks in advance for any help!

  Read the article

• Cross-reference between delphi records

  - by Paul-Jan

  Let's say I have a record TQuaternion and a record TVector. Quaternions have some methods with TVector parameters. On the other hand, TVector supports some operations that have TQuaternion parameters. Knowing that Delphi (Win32) does not allow for forward record declarations, how do I solve this elegantly? Using classes is not really an option here, because I really want to use operator overloading for this rare case where it actually makes good sense. For now I simply moved these particular methods out of the records and into separate functions, the good old-fashioned way. Better suggestions are most welcome.

  Read the article

• How to convert an HTML table to an array in python

  - by user345660

  I have an html document, and I want to pull the tables out of this document and return them as arrays. I'm picturing 2 functions, one that finds all the html tables in a document, and a second one that turns html tables into 2-dimensional arrays. Something like this: htmltables = get_tables(htmldocument) for table in htmltables: array=make_array(table) There's 2 catches: 1. The number tables varies day to day 2. The tables have all kinds of weird extra formatting, like bold and blink tags, randomly thrown in. Thanks!

  Read the article

• Show duplicates in Mathematica

  - by Martin Janiczek

  In Mathematica I have a list: x = {1,2,3,3,4,5,5,6} How will I make a list with the duplicates? Like: {3,5} I have been looking at Lists as Sets, if there is something like Except[] for lists, so I could do: unique = Union[x] duplicates = MyExcept[x,unique] (Of course, if the x would have more than two duplicates - say, {1,2,2,2,3,4,4}, there the output would be {2,2,4}, but additional Union[] would solve this.) But there wasn't anything like that (if I did understand all the functions there well). So, how to do that?

  Read the article

• What is the current state of Unit testing support in the R language

  - by PaulHurleyuk

  R is a statistics programming language. Part of R is the use of Packages, which themselves are written in the R language. Programming best practice includes the use of unit-testing to test the functions within these packages while they are being written and when they are used. I am aware of a few packages for unit testing within R, these being RUnit Svunit Testthat I'm interested to know; Are there any other packages out there ? Given peoples experience, do these packages excel at different things ? What's the current state of the art in unit testing for R ?

  Read the article

• How do you get notified of your repos' updates?

  - by furtelwart

  I'm working on several repositories at work and would like to be informed, if anything changes in the SVN repositories. I made a small BAT script (yes, BAT is usefull sometimes) that keeps executing an svn log -r BASE:HEAD on my working copy. It shows all submit comments and revision dates. It works really well but it's not comfortable for different repositories. How do you keep track of changes in your repositories? Do you use a small program you made for yourself? Do you use software someone else made? I'm interested in every approach to this problem. I would like to get notifications and several more information about the commit. The IDE integrated functions are good, but work only if I request the information. I don't want to act to get this information. Platform: Windows, Subversion 1.5 and higher.

  Read the article

< Previous Page | 337 338 339 340 341 342 343 344 345 346 347 348  | Next Page >