I really need your help. I'm trying to call the function found in Oka's library called stepping_isProbablePrime(t). It allows me to call this function asynchronously. The problem is I'm so new to Javascript I can't comprehend how I can call this function within a loop.
http://ats.oka.nu/titaniumcore/js/crypto/RSA.sample1.html
http://ats.oka.nu/titaniumcore/js/nonstructured/nonstructured.readme.txt
Those two links lead to an example of the prime number generation he's done, and the second link leads to the structure that handles the asychronous calls. Also note that if you open the library to try and call this function yourself, the function is found within biginteger.init3.js.
http://ats.oka.nu/titaniumcore/js/crypto/readme.txt
Here's one more link just for a general overview of his library. I really need your help guys, I've tried contacting the writer, and I've tried reddit. As well as countless hours trying to grasp and implement this function by reading whatever I can find.
Related
I want to write a modular matlab program and I have some data structures such as history in my program. Is that true that I have to keep all my data-structures in the main script of my program? In other words if I have some arrays and fields of data, if I put them in other m files, such as functions, they are temporal and they are going to be collected as garbage in my program execution. I am a java developer and now I want to develop some code in matlab.
As Tommaso suggested in a comment, you should use classes. Look at the documentation for classdef to get started. The full documentation to create classes starts at this page.
But to directly answer your question: it is possible to store static data in functions: see persistent.
If you're making a GUI, there are built-in ways to store data, see guidata.
Finally, there is also getappdata and setappdata, which set global variables but specific to one app.
For all that's good in this world, don't use global, it's not worth the hassle, here are plenty of better alternatives.
PS: if the links here break, note that it is always possible to type help <cmd> to get help on one of the functions mentioned here.
I have heard this term tossed around, can anybody explain what it means and what problem it solves. Also where does this originate from.
Simplified it's when you pass a function to another function, and that other function call you back using the function you passed.
It's useful for asynchronous programming, when events can happen at any time. Or for generic handling of certain functionality to make some algorithms more generic (for example in C++ you can pass a comparison function to the std::sort function, and your comparison function will be used to compare two items when sorting).
I need to rewrite the linkage function in matlab. Now, as I examine it, I realized there is a method called linkagemex inside of it. But I simply cannot step into this method to see its code. Can anyone help me out with this strange situastion?
function Z= linkage (Y, method, pdistArg, varargin)
Z=linkagemex(Y,method);
PS. I think I am pretty good at learning, but matlab is not so easy to learn. If you have good references to learn it well, feel free to let me know. Thanks very much for your time and attention.
As #m.s. mentions, you've found a call to a MEX function. MEX functions are implemented as C code that is compiled into a function callable by MATLAB.
As you've found, you can't step into this method (as it is compiled C code, not MATLAB code), and you don't have access to the C source code, as it's not supplied with MATLAB.
Normally, you would be at kind of a dead end here. Fortunately, that's not quite the case with linkagemex. You'll notice on line 240 of linkage.m that it actually does a test to see whether linkagemex is present. If it isn't, it instead calls a local subfunction linkageold.
I think you can assume that linkageold does at least roughly the same thing as linkagemex. You may like to test them out with a few suitable input arguments to see if they give the same results. If so, then you should be able to rewrite linkage using the code from linkageold rather than linkagemex.
I'm going to comment more generally, related to your PS. Over the last few days I've been answering a few of your questions - and you do seem like a fast learner. But it's not really that MATLAB is hard to learn - you should realize that what you're attempting (rewriting the clustering behaviour of phytree) is not an easy thing to do for even a very advanced user.
MathWorks write their stuff in a way that makes it (hopefully) easy to use - but not necessarily in a way that makes it easy for users to extend or modify. Sometimes they do things for performance reasons that make it impossible for you to modify, as you've found with linkagemex. In addition, phytree is implemented using an old style of OO programming that is no longer properly documented, so even if you have the code, it's difficult to work out what it even does, unless you happen to have been working with MATLAB for years and remember how the old style worked.
My advice would be that you might find it easier to just implement your own clustering method from scratch, rather than trying to build on top of phytree. There will be a lot of further headaches for you down the road you're on, and mostly what you'll learn is that phytree is implemented in an obscure old-fashioned way. If you take the opportunity to implement your own from scratch, you could instead be learning how to implement things using more modern OO methods, which would be more useful for you in the future.
Your call though, that's just my thoughts. Happy to continue trying to answer questions when I can, if you choose to continue with the phytree route.
You came across a MEX function, which "are dynamically linked subroutines that the MATLAB interpreter loads and executes". Since these subroutines are natively compiled, you cannot step into them. See also the MATLAB documentation about MEX functions.
I've been working with layers for MapKit on the iPhone, and one library that I came across was this one: https://github.com/mtigas/iOS-MapLayerDemo/. It's very helpful, and seems to work fine. However, I'm trying to go through and understand a bit how it works, but I'm having some trouble.
On this page, for example: https://github.com/mtigas/iOS-MapLayerDemo/blob/master/MapLayerDemo/Classes/CustomOverlayView.m,
at the top, there are 4 custom functions defined. I assume these functions are adding on to the normal features of MKOverlayView? The thing is, I can't find where any of these new functions are actually called from, and thus I'm having some trouble understanding how this page works. It doesn't seem to be from any of the other files within the project.
I appreciate any help, thanks.
After some extended discussion with you in comments:
The override-able functions of MKOverlayView, such as canDrawMapRect cannot easily be traced back to their calling code because that code is obfuscated somewhere in the MapKit.framework.
Instead, the typical approach is to re-read their documentation until you get a mental picture of what the framework is using the function for. (There is such a thing as decompiling binaries, although that is generally frowned upon and I do not recommend it.)
canDrawMapRect documentation: http://developer.apple.com/library/ios/documentation/MapKit/Reference/MKOverlayView_class/Reference/Reference.html#//apple_ref/doc/uid/TP40009715-CH1-SW10
After reading their documentation, I inferred this: Somewhere in the MapKit.framework, canDrawMapRect is being called prior to actually drawing the view. If you didn't override that function in your subclass, it calls the super-class's default implementation, which always returns YES and then calls drawMapRect: (Which MUST be overridden if you are subclassing MKOverlayView, or else nothing will draw!)
The class you linked above potentially returns NO. In that particular case, it appears the code in MapKit.framework skips calling drawMapRect: and nothing is displayed (or refreshed).
So, long story short: for this case, you have to play code-detective and hope the documentation is written clearly enough to figure it out without being able to see all of the code.
Edit: Just to further clarify - It appears MKOverlayView must be subclassed to actually generate something visible.
My original answer before getting to your underlying question --
Short answer: Those are private functions for use within that class.
Long answer: Functions declared in an empty-name category at the top
of implementation files are visible only to the class the category is
extending. Thus, those functions can only be called within that
class's implementation. (C++ equivalent would just be declaring the
functions private)
3 of those 4 functions are called within that same .m file. Without
digging around, I'm guessing they wrote the first function and then
later decided to not use it.
I'm creating an app in which I do the same thing multiple times. I'm going for as little code as possible and I don't want to repeat myself.
I need the PHP equivalant of a reusable function, where I set an input, and the function will return the output.
The app is a URL shortener, so the input as you may assume is a URL, and the output is the short URL.
What's the best way to go about this? I know I can code the same thing twice, but I hate to repeat myself.
Hopefully I'm getting my point across. Any help is greatly appreciated.
-Giles
Apologies if I'm oversimplifying your question, but are you asking how to define an Objective-C method? If so, you're going to have to learn Objective-C, there's no way around it:
The Objective-C Programming Language - Object Messaging
You can do a lot of great things with no code on the iPhone and Mac platforms, but it's hard to imagine completing any useful application without writing some code.
Example
- (float)multiplyThisFloatByTwoPointFive:(float)numberToMultiply
{
return numberToMultiply * 2.5;
}
To call it:
[self multiplyThisFloatByTwoPointFive:3.7];
Libraries
If you mean "I want to put these non-class-specific methods somewhere I can access them universally", eg, a library, you can do this in two ways:
Create some sort of "library" class like "MySpecialMathClass" (not to be confused with "my special education math class") or "MyAppAnimationTricks" and put your methods there (you'd define them as +someMethod: not -someMethod:, class- not instance-method, per Objective-C).
If they only ever deal with primitives (such as int, float, double ...), consider just making them C functions, rather than Objective-C methods.
I am pretty much a newbie at this, but you can certainly write functions (as opposed to methods) in Objective C.
I wrote several utility functions recently. I created an NSObject file to place them in, but it has no ivars or methods declared, just the functions. Then implement the functions in the .m file, and import the .h file into any class file where you want the functions. You can obviously call these from anywhere in any .m file that has imported the function file.
John Doner