When should I use ConcurrentSkipListMap?
In Java, ConcurrentHashMap is there for better multithreading solution. Then when should I use ConcurrentSkipListMap? Is it a redundancy? Does multithreading aspects between these two are common? ...
map
adding a map overlay on a UK Ordnance Survey OpenSpace map
Does anyone have a code example of how to add an image overlay to an Ordnance Survey OpenSpace map? The documentation is not exactly comprehensive :) Thanks! ...
Why <C-PageUp> and <C-PageDown> not work in vim?
I have vim 7.2 installed in my windows. In gvim, the and works for navigation among tabs by default. However, it doesn't work for vim. Even I have below lines in _vimrc added. It still not work. map <C-PageUp> :tabp<CR> map <C-PageDown> :tabn<CR> But, map and works. map <C-left> :tabp<CR> map <C-right> :tabn<CR> Anybody has cl...
Optimizing map drawing
Hello, I have problem optimizing drawing Google-like map. It works OK for hundreds of points, but when it comes to larger amounts like thousands it gets fuzzy and slow. Also unzoomed it looks weird. I'd like to know how to optimize drawing algorithm to draw fewer places so it looks like unzooming on Google Maps. However I also draw lin...
C++ map insertion and lookup performance and storage overhead
I would like to store a mapping of an integer key to a float value in-memory. I have roughly 130 million keys (and, accordingly, 130 million values). My focus is on lookup performance -- I have to do many, many millions of lookups. The C++ STL library has a map class for associative arrays of this sort. I have several questions abou...
Origin of "map" in Computer Science
In computer science, there are two definitions of the word map. The first is as an associative array, a type of container that maps values of one type to values of another type. An example of this is the STL map. The second definition is from functional programming, in which map applies is a function that takes a list and a function, app...
Rotate MapView in Android
Hi, I am writing an Android app where one of the features is that the map will rotate according to the compass (i.e. if the phone is pointing east, the map will be oriented so that the east side of the map is on top). Previous answers that I have found suggested over writing the onDraw() method in mapView, however, the api changed the ...
how to efficiently track the use of space on a map, both objects and free areas.
OK I start with a blank map, which is 512x512 = 262144 pixels/locations. I need a way to efficiently draw some objects on it, and then be able to find the areas of free space, so that later more different objects can be added to these free areas. I cant figure out the best way to store this data, or algorithms to find the free areas. I...
How to reduce the total memory hogging by compacting my Objects in Java?
I have a table with around 20 columns with mostly consisting of varchars and decimals. This table has almost 1.5M rows. But few things are common in them like column1 consists of only 100 distinct strings , column2 has almost 1000 and column3 has almost 500. Right now, I am storing all these column values in a map with Key as first 5 c...
Mapping a WebDAV folder (WebFolder) to a drive - C#
Hi, I'm working on a WebDAV Application.. I can now connect to an ip, say, http://localhost:9005/MyWeb/ by creating a web folder. I could create and delete the web folder using C# code... I could traverse my web folder thoroughly... Is it possible for me to map this web folder to a new drive (using C#) so that I can access the contents f...
How to get post codes with given postcode and distance in miles or km?
Hi, My site needs postcodes display with given post code and distance (miles or km). I have to implement it using google api. Is it possible to do so? The country for which i need to use this is Australia. I am trying to find out the solution for two days. Can anyone help me out. Thanks in advance ...
What _can_ I use as std::map keys?
Extends. I have: struct Coord { int row, col ; bool operator<( const Coord other.row other.col ; } } ; I'm trying to create a map<Coord, Node*>, where you can look up a Node* by Coord. The problem is, it has bugs. Lookups into the map<Coord, Node*> by Coord are returning the wrong ones. I'm having difficulty figuring out ...
Heatmap (density map) on GWT
I want to creata a heatmap (density map) on images. The examples like the one in http://www.heatmapapi.com/Sample%5FGoogle.aspx are good examples of what I try to do. Is there a GWT way of achieving this? Or any good (flash or js) solution you can suggest (other then the ones mentioned http://stackoverflow.com/questions/357721/heatmap-t...
How to pass items as args lists in map?
This is a piece of my code. Lambda accepts 3 parameters, and I wanted to pass them as a tuple of positional arguments, but apparently map supplies them as a single argument. How can I supply those tuples in the bottom as lists of arguments? (I know I can rewrite the lambda, but it will become not well readable) adds = map((lambda j, f...
Message Map in Win32 No-MFC
How could I create similar structure to handle Win32 Messages like it is in MFC? In MFC; BEGIN_MESSAGE_MAP(CSkinCtrlTestDlg, CDialog) //{{AFX_MSG_MAP(CSkinCtrlTestDlg) ON_BN_CLICKED(IDC_BROWSE, OnBrowse) ON_BN_CLICKED(IDC_DEFAULTSKIN, OnChangeSkin) ON_WM_DRAWITEM() ON_WM_MEASUREITEM() ON_WM_COMPAREITEM() ON_...
C++ "Scrolling" through items in an stl::map
I've made a method to scroll/wrap around a map of items, so that if the end is reached, the method returns the first item and vice-versa. Is there more succinct way of doing this? MyMap::const_iterator it = myMap.find(myKey); if (it == myMap.end()) return 0; if (forward) { it++; if (it == myMap.end()) { it = myM...
Is there any free/open source map engine for iPhone?
Hi I have a bunch of map images and i wonder if there is any free/open source map engine that I can use for iPhone development. Just like google map api but they are for native development ...
Mapping mouse events in vim through putty not working...
I'm using Vim 6.3.81 on a x-term through putty. I wanted to map mouse events (like wheel-button click , double click) to specific events using my .vimrc . I've looked at the vim wiki and based on it, defined the following map in my .vimrc: :nnoremap <2-LeftMouse> :set invnumber<CR> However , it is not working - double-click is not tog...
Marking the Initial State of this Finite Automaton
I'm working on a finite deterministic automaton based on this. From this code: public void markInitialState (int initialStateId) { State theInitialState = allStates.get(initialStateId); theInitialState.isInitial=true; allStates.add(initialStateId, theInitialState); ...
traditional for loop vs Iterator in Java
Is there any performance testing results available in comparing traditional for loop vs Iterator while traversing a ArrayList,HashMap and other collections? Or simply why should I use Iterator over for loop or vice versa? ...