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  • General Address Parser for Freeform Text

    - by Daemonic
    We have a program that displays map data (think Google Maps, but with much more interactivity and custom layers for our clients). We allow navigation via a set of combo boxes that prefill certain fields with a bunch of data (ie: Country: Canada, the Province field is filled in. Select Ontario, and a list of Counties/Regions is filled in. Select a county/region, and a city is filled in, etc...). While this guarantees accurate addresses, it's a pain for the users if they don't know where a street address or a city are located (ie, which county/region is kitchener in?). So we are looking at trying to do an address parser with a freeform text field. The user could enter something like this (similar to Google Maps, Bing Maps, etc...): 22 Main St, Kitchener, On And we could compartmentalize it into sections and do lookups on the data and get to the point they are looking for (or suggest alternatives). The problem with this is that how do we properly compartmentalize information? How do we break up the sections and find possible matches? I'm guessing we wouldn't be guaranteed that the user would enter data in a format we always expected (obviously). A follow up to this would be how to present the data if we don't find an exact match (or find multiple exact matches... two cities with the same street name in different counties, for example). We have a ton of data available in the mapping data (mapinfo tab format mostly). So we can do quick scans of street names, cities, states, etc. But I'm not sure about the best way to go about approaching this problem. Sure, using Google Maps would be nice, bue most of our clients are in closed in networks where outside access is not usually allowed and most aren't willing to rely on google maps (since it doesn't contain as much information as they need, such as custom map layers). They could, obviously, go to google and get the proper location then move to our software, but this would time consuming and speed of the process can be quite important.

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  • Python script to calculate aded combinations from a dictionary

    - by dayde
    I am trying to write a script that will take a dictionary of items, each containing properties of values from 0 - 10, and add the various elements to select which combination of items achieve the desired totals. I also need the script to do this, using only items that have the same "slot" in common. For example: item_list = { 'item_1': {'slot': 'top', 'prop_a': 2, 'prop_b': 0, 'prop_c': 2, 'prop_d': 1 }, 'item_2': {'slot': 'top', 'prop_a': 5, 'prop_b': 0, 'prop_c': 1, 'prop_d':-1 }, 'item_3': {'slot': 'top', 'prop_a': 2, 'prop_b': 5, 'prop_c': 2, 'prop_d':-2 }, 'item_4': {'slot': 'mid', 'prop_a': 5, 'prop_b': 5, 'prop_c':-5, 'prop_d': 0 }, 'item_5': {'slot': 'mid', 'prop_a':10, 'prop_b': 0, 'prop_c':-5, 'prop_d': 0 }, 'item_6': {'slot': 'mid', 'prop_a':-5, 'prop_b': 2, 'prop_c': 3, 'prop_d': 5 }, 'item_7': {'slot': 'bot', 'prop_a': 1, 'prop_b': 3, 'prop_c':-4, 'prop_d': 4 }, 'item_8': {'slot': 'bot', 'prop_a': 2, 'prop_b': 2, 'prop_c': 0, 'prop_d': 0 }, 'item_9': {'slot': 'bot', 'prop_a': 3, 'prop_b': 1, 'prop_c': 4, 'prop_d':-4 }, } The script would then need to select which combinations from the "item_list" dict that using 1 item per "slot" that would achieve a desired result when added. For example, if the desired result was: 'prop_a': 3, 'prop_b': 3, 'prop_c': 8, 'prop_d': 0, the script would select 'item_2', 'item_6', and 'item_9', along with any other combination that worked. 'item_2': {'slot': 'top', 'prop_a': 5, 'prop_b': 0, 'prop_c': 1, 'prop_d':-1 } 'item_6': {'slot': 'mid', 'prop_a':-5, 'prop_b': 2, 'prop_c': 3, 'prop_d': 5 } 'item_9': {'slot': 'bot', 'prop_a': 3, 'prop_b': 1, 'prop_c': 4, 'prop_d':-4 } 'total': 'prop_a': 3, 'prop_b': 3, 'prop_c': 8, 'prop_d': 0 Any ideas how to accomplish this? It does not need to be in python, or even a thorough script, but just an explanation on how to do this in theory would be enough for me. I have tried working out looping through every combination, but that seems to very quickly get our of hand and unmanageable. The actual script will need to do this for about 1,000 items using 20 different "slots", each with 8 properties. Thanks for the help!

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  • Efficient data structure design

    - by Sway
    Hi there, I need to match a series of user inputed words against a large dictionary of words (to ensure the entered value exists). So if the user entered: "orange" it should match an entry "orange' in the dictionary. Now the catch is that the user can also enter a wildcard or series of wildcard characters like say "or__ge" which would also match "orange" The key requirements are: * this should be as fast as possible. * use the smallest amount of memory to achieve it. If the size of the word list was small I could use a string containing all the words and use regular expressions. however given that the word list could contain potentially hundreds of thousands of enteries I'm assuming this wouldn't work. So is some sort of 'tree' be the way to go for this...? Any thoughts or suggestions on this would be totally appreciated! Thanks in advance, Matt

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  • Why does C qicksort function implementation works much slower (tape comparations, tape swapping) than bobble sort function?

    - by Artur Mustafin
    I'm going to implement a toy tape "mainframe" for a students, showing the quickness of "quicksort" class functions (recursive or not, does not really matters, due to the slow hardware, and well known stack reversal techniques) comparatively to the "bubblesort" function class, so, while I'm clear about the hardware implementation ans controllers, i guessed that quicksort function is much faster that other ones in terms of sequence, order and comparation distance (it is much faster to rewind the tape from the middle than from the very end, because of different speed of rewind). Unfortunately, this is not the true, this simple "bubble" code shows great improvements comparatively to the "quicksort" functions in terms of comparison distances, direction and number of comparisons and writes. So I have 3 questions: Does I have mistaken in my implememtation of quicksort function? Does I have mistaken in my implememtation of bubblesoft function? If not, why the "bubblesort" function is works much faster in (comparison and write operations) than "quicksort" function? I already have a "quicksort" function: void quicksort(float *a, long l, long r, const compare_function& compare) { long i=l, j=r, temp, m=(l+r)/2; if (l == r) return; if (l == r-1) { if (compare(a, l, r)) { swap(a, l, r); } return; } if (l < r-1) { while (1) { i = l; j = r; while (i < m && !compare(a, i, m)) i++; while (m < j && !compare(a, m, j)) j--; if (i >= j) { break; } swap(a, i, j); } if (l < m) quicksort(a, l, m, compare); if (m < r) quicksort(a, m, r, compare); return; } } and the kind of my own implememtation of the "bubblesort" function: void bubblesort(float *a, long l, long r, const compare_function& compare) { long i, j, k; if (l == r) { return; } if (l == r-1) { if (compare(a, l, r)) { swap(a, l, r); } return; } if (l < r-1) { while(l < r) { i = l; j = l; while (i < r) { i++; if (!compare(a, j, i)) { continue; } j = i; } if (l < j) { swap(a, l, j); } l++; i = r; k = r; while(l < i) { i--; if (!compare(a, i, k)) { continue; } k = i; } if (k < r) { swap(a, k, r); } r--; } return; } } I have used this sort functions in a test sample code, like this: #include <stdio.h> #include <stdlib.h> #include <math.h> #include <conio.h> long swap_count; long compare_count; typedef long (*compare_function)(float *, long, long ); typedef void (*sort_function)(float *, long , long , const compare_function& ); void init(float *, long ); void print(float *, long ); void sort(float *, long, const sort_function& ); void swap(float *a, long l, long r); long less(float *a, long l, long r); long greater(float *a, long l, long r); void bubblesort(float *, long , long , const compare_function& ); void quicksort(float *, long , long , const compare_function& ); void main() { int n; printf("n="); scanf("%d",&n); printf("\r\n"); long i; float *a = (float *)malloc(n*n*sizeof(float)); sort(a, n, &bubblesort); print(a, n); sort(a, n, &quicksort); print(a, n); free(a); } long less(float *a, long l, long r) { compare_count++; return *(a+l) < *(a+r) ? 1 : 0; } long greater(float *a, long l, long r) { compare_count++; return *(a+l) > *(a+r) ? 1 : 0; } void swap(float *a, long l, long r) { swap_count++; float temp; temp = *(a+l); *(a+l) = *(a+r); *(a+r) = temp; } float tg(float x) { return tan(x); } float ctg(float x) { return 1.0/tan(x); } void init(float *m,long n) { long i,j; for (i = 0; i < n; i++) { for (j=0; j< n; j++) { m[i + j*n] = tg(0.2*(i+1)) + ctg(0.3*(j+1)); } } } void print(float *m, long n) { long i, j; for(i = 0; i < n; i++) { for(j = 0; j < n; j++) { printf(" %5.1f", m[i + j*n]); } printf("\r\n"); } printf("\r\n"); } void sort(float *a, long n, const sort_function& sort) { long i, sort_compare = 0, sort_swap = 0; init(a,n); for(i = 0; i < n*n; i+=n) { if (fmod (i / n, 2) == 0) { compare_count = 0; swap_count = 0; sort(a, i, i+n-1, &less); if (swap_count == 0) { compare_count = 0; sort(a, i, i+n-1, &greater); } sort_compare += compare_count; sort_swap += swap_count; } } printf("compare=%ld\r\n", sort_compare); printf("swap=%ld\r\n", sort_swap); printf("\r\n"); }

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  • CODE1 Spoj - cannot solve it

    - by VaioIsBorn
    I am trying to solve the problem Secret Code and it's obviously math problem. The full problem For those who are lazy to go and read, it's like this: a0,a1,a2,...,an - sequence of N numbers B - some number known to us X = a0 + a1*B + a2*(B^2) + a3*(B^3) + ... + an*(B^n) So if you are given B and X, you should find a0,a1,..an. I don't know how or where to start, because not even N is known, just X and B. Can you help me ?

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  • Interpolating in HSV color space

    - by user146780
    I have an HSV color A at 3/10 of a line and HSV color B at 9/10 of a line. I'm making multistep gradients and for example if I wanted to find the color at 6/10ths of a line, how could I interpolate these HSV colors? I'm firmiliar with the technique for rgb but not HSV. I should also add that my HSV's are integers H(0,360) S(0,100) V(0,100). Thanks

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  • Android Compass orientation on unreliable (Low pass filter)

    - by madsleejensen
    Hi all Im creating an application where i need to position a ImageView depending on the Orientation of the device. I use the values from a MagneticField and Accelerometer Sensors to calculate the device orientation with SensorManager.getRotationMatrix(rotationMatrix, null, accelerometerValues, magneticFieldValues) SensorManager.getOrientation(rotationMatrix, values); double degrees = Math.toDegrees(values[0]); My problem is that the positioning of the ImageView is very sensitive to changes in the orientation. Making the imageview constantly jumping around the screen. (because the degrees change) I read that this can be because my device is close to things that can affect the magneticfield readings. But this is not the only reason it seems. I tried downloading some applications and found that the "3D compass" application remains extremely steady in its readings, i would like the same behavior in my application. I read that i can tweak the "noise" of my readings by adding a "Low pass filter", but i have no idea how to implement this (because of my lack of Math). Im hoping someone can help me creating a more steady reading on my device, Where a little movement to the device wont affect the current orientation. Right now i do a small if (Math.abs(lastReadingDegrees - newReadingDegrees) > 1) { updatePosition() } To filter abit of the noise. But its not working very well :)

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  • Texture coordintes for a polygon and a square texture

    - by user146780
    basically I have a texture. I also have a lets say octagon (or any polygon). I find that octagon's bounding box. Let's say my texture is the size of the octagon's bounding box. How could I figure out the texture coordinates so that the texture maps to it. To clarify, lets say you had a square of tin foil and cut the octagon out you'd be left with a tin foil textured polygon.I'm just not sure how to figure it out for an arbitrary polygon. Thanks

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  • String operations

    - by NEO
    I am trying to find the most repeated word in a string. My code is as follows: public class Word { private String toWord; private int Count; public Word(int count, String word){ toWord = word; Count = count; } public static void main(String args[]){ String str="my name is neo and my other name is also neo because I am neo"; String []str1=str.split(" "); Word w1=new Word(0,str1[0]); LinkedList<Word> list = new LinkedList<Word>(); list.add(w1); ListIterator itr = list.listIterator(); for(int i=1;i<str1.length;i++){ while(itr.hasNext()){ if(str1[i].equalsTO(????)); else list.add(new Word(0,str1[i])); } How do I compare the string from string array str1 to the string stored in the linked list and then how do i increase the respective count. I will then print the string with the highest count, I dont know how to do that either.

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  • nth smallest number among two databases of size n each using divide and conquer

    - by urfriend
    we have two databases of size n containing numbers without repeats. So, in total we have 2n elements. They can be accessed through a query to one database at a time. The query is such that you give it a k and it returns kth smallest entry in that database. we need to find nth smallest entry among all the 2n elements in O(logn) queries. the idea is to use divide and conquer but i need some help thinking through this. thanks!

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  • Detecting one point's location compared to two other points.

    - by WizardOfOdds
    Hi all, you can check my profile, this is not homework. I've got an interesting little problem to solve in a very real software and I'm looking for an easy way to solve it. I've got two fixed points on screen (they're fixed, but I don't know beforehand their position) that are not at the same location. These two fixed points form an imaginary line. Now I've got a third point that is "on one side" of that line (it cannot be on the line). The user can grab the point (the user actually grab an object, whose I track by its center, which is the point I'm interested in) and drag it. But it cannot "cross" the imaginary line. What is the easiest way to detect if the user is crossing the imaginary line? Example: a c / / (c cannot be dragged here) / b Or: c b -------------- a (c cannot be dragged here) So what is an easy to detect if c is staying on the correct "side" of the line (I draw segments here, but it really can be thought of as a line). One way to detect this is to take the destination point d and see if segment (c,d) intersects with line (a,b), but isn't there an easier way? Can't I just do some 2D dot-product magic here and have basically a one or two liner solving my issue?

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  • ListAdapters and WrapperListAdapter algorithm

    - by Matty F
    This logic is written in a function with signature private void showDialog(final AdapterView<? extends Adapter> parent, String title, String message, final Tag subject) Is there a better way of doing this? // refresh adapter SimpleCursorAdapter adapter; if (parent.getAdapter() instanceof WrapperListAdapter) { adapter = (SimpleCursorAdapter) ((WrapperListAdapter) parent.getAdapter()).getWrappedAdapter(); } else { adapter = (SimpleCursorAdapter) parent.getAdapter(); } adapter.getCursor().requery(); adapter.notifyDataSetChanged(); Also, is there any point in having AdapterView<? extends Adapter> in the signature and not just AdapterView<?>?

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  • Could a truly random number be generated using pings to psuedo-randomly selected IP addresses?

    - by _ande_turner_
    The question posed came about during a 2nd Year Comp Science lecture while discussing the impossibility of generating numbers in a deterministic computational device. This was the only suggestion which didn't depend on non-commodity-class hardware. Subsequently nobody would put their reputation on the line to argue definitively for or against it. Anyone care to make a stand for or against. If so, how about a mention as to a possible implementation?

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  • Is it possible to create thread-safe collections without locks?

    - by Andrey
    This is pure just for interest question, any sort of questions are welcome. So is it possible to create thread-safe collections without any locks? By locks I mean any thread synchronization mechanisms, including Mutex, Semaphore, and even Interlocked, all of them. Is it possible at user level, without calling system functions? Ok, may be implementation is not effective, i am interested in theoretical possibility. If not what is the minimum means to do it? EDIT: Why immutable collections don't work. This of class Stack with methods Add that returns another Stack. Now here is program: Stack stack = new ...; ThreadedMethod() { loop { //Do the loop stack = stack.Add(element); } } this expression stack = stack.Add(element) is not atomic, and you can overwrite new stack from other thread. Thanks, Andrey

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  • Chain call in clojure?

    - by Konrad Garus
    I'm trying to implement sieve of Eratosthenes in Clojure. One approach I would like to test is this: Get range (2 3 4 5 6 ... N) For 2 <= i <= N Pass my range through filter that removes multiplies of i For i+1th iteration, use result of the previous filtering I know I could do it with loop/recur, but this is causing stack overflow errors (for some reason tail call optimization is not applied). How can I do it iteratively? I mean invoking N calls to the same routine, passing result of ith iteration to i+1th.

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  • Encoding arbitrary data into numbers?

    - by Pekka
    Is there a common method to encode and decode arbitrary data so the encoded end result consists of numbers only - like base64_encode but without the letters? Fictitious example: $encoded = numbers_encode("Mary had a little lamb"); echo $encoded; // outputs e.g. 122384337422394237423 (fictitious result) $decoded = numbers_decode("122384337422394237423"); echo $decoded; // outputs "Mary had a little lamb"

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  • Learning Algorithms and Data Structures Fundamentals

    - by valya
    Can you recommend me a book or (better!) a site with many hard problems and exercises about data structures? I'm already answering project Euler questions, but these questions are about interesting, but uncommon algorithms. I hardly used even a simple tree. Maybe there is a site with exercises like: hey, you need to calculate this: ... . Do it using a tree. Now do it using a zipper. Upload your C (Haskell, Lisp, even Pascal or Fortress go) solution. Oh, your solution is so slow! Self-education is very hard then you trying to learn very common, fundamental things. How can I help myself with them without attending to courses or whatever?

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  • problem with evolutionary algorithms degrading into simulated annealing: mutation too small?

    - by Schnalle
    i have a problem understanding evolutionary algorithms. i tried using this technique several times, but i always ran into the same problem: degeneration into simulated annealing. lets say my initial population, with fitness in brackets, is: A (7), B (9), C (14), D (19) after mating and mutation i have following children: AB (8.3), AC (12.2), AD (14.1), BC(11), BD (14.7), CD (17) after elimination of the weakest, we get A, AB, B, AC next turn, AB will mate again with a result around 8, pushing AC out. next turn, AB again, pushing B out (assuming mutation changes fitness mostly in the 1 range). now, after only a few turns the pool is populated with the originally fittest candidates (A, B) and mutations of those two (AB). this happens regardless of the size of the initial pool, it just takes a bit longer. say, with an initial population of 50 it takes 50 turns, then all others are eliminated, turning the whole setup in a more complicated simulated annealing. in the beginning i also mated canditates with themselves, worsening the problem. so, what do i miss? are my mutation rates simply too small and will it go away if i increase them? here's the project i'm using it for: http://stefan.schallerl.com/simuan-grid-grad/ yeah, the code is buggy and the interface sucks, but i'm too lazy to fix it right now - and be careful, it may lock up your browser. better use chrome, even thought firefox is not slower than chrome for once (probably the tracing for the image comparison pays off, yay!). if anyone is interested, the code can be found here. here i just dropped the ev-alg idea and went for simulated annealing. ps: i'm not even sure about simulated annealing - it is like evolutionary algorithms, just with a population size of one, right?

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  • Best data-structure to use for two ended sorted list

    - by fmark
    I need a collection data-structure that can do the following: Be sorted Allow me to quickly pop values off the front and back of the list Remain sorted after I insert a new value Allow a user-specified comparison function, as I will be storing tuples and want to sort on a particular value Thread-safety is not required Optionally allow efficient haskey() lookups (I'm happy to maintain a separate hash-table for this though) My thoughts at this stage are that I need a priority queue and a hash table, although I don't know if I can quickly pop values off both ends of a priority queue. I'm interested in performance for a moderate number of items (I would estimate less than 200,000). Another possibility is simply maintaining an OrderedDictionary and doing an insertion sort it every-time I add more data to it. Furthermore, are there any particular implementations in Python. I would really like to avoid writing this code myself.

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  • Whats the difference between Paxos and W+R>=N in Cassandra?

    - by user1128016
    Dynamo-like databases (e.g. Cassandra) provide ability to enforce consistency by means of quorum, i.e. a number of synchronously written replicas (W) and a number of replicas to read (R) should be chosen in such a way that W+RN where N is a replication factor. On the other hand, PAXOS-based systems like Zookeeper are also used as a consistent fault-tolerant storage. What is the difference between these two approaches? Does PAXOS provide guarantees that are not provided by W+RN schema?

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