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Search found 73 results on 3 pages for 'modulo'.

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  • Modulo in JavaScript - large number

    - by Benedikt R.
    Hi! I try to calculate with JS' modulo function, but don't get the right result (which should be 1). Here is a hardcoded piece of code. var checkSum = 210501700012345678131468; alert(checkSum % 97); Result: 66 Whats the problem here? Regards, Benedikt

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  • Modulo operator in Objective-C returns the wrong result

    - by Greg Maletic
    I'm a little freaked out by the results I'm getting when I do modulo arithmetic in Objective-C. -1 % 3 is coming out to be -1, which isn't the right answer: according to my understanding, it should be 2. -2 % 3 is coming out to -2, which also isn't right: it should be 1. Is there another method I should be using besides the % operator to get the correct result?

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  • Better ways to implement a modulo operation (algorithm question)

    - by ryxxui
    I've been trying to implement a modular exponentiator recently. I'm writing the code in VHDL, but I'm looking for advice of a more algorithmic nature. The main component of the modular exponentiator is a modular multiplier which I also have to implement myself. I haven't had any problems with the multiplication algorithm- it's just adding and shifting and I've done a good job of figuring out what all of my variables mean so that I can multiply in a pretty reasonable amount of time. The problem that I'm having is with implementing the modulus operation in the multiplier. I know that performing repeated subtractions will work, but it will also be slow. I found out that I could shift the modulus to effectively subtract large multiples of the modulus but I think there might still be better ways to do this. The algorithm that I'm using works something like this (weird pseudocode follows): result,modulus : integer (n bits) (previously defined) shiftcount : integer (initialized to zero) while( (modulus<result) and (modulus(n-1) != 1) ){ modulus = modulus << 1 shiftcount++ } for(i=shiftcount;i>=0;i++){ if(modulus<result){result = result-modulus} if(i!=0){modulus = modulus << 1} } So...is this a good algorithm, or at least a good place to start? Wikipedia doesn't really discuss algorithms for implementing the modulo operation, and whenever I try to search elsewhere I find really interesting but incredibly complicated (and often unrelated) research papers and publications. If there's an obvious way to implement this that I'm not seeing, I'd really appreciate some feedback.

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  • power and modulo on the fly for big numbers

    - by user unknown
    I raise some basis b to the power p and take the modulo m of that. Let's assume b=55170 or 55172 and m=3043839241 (which happens to be the square of 55171). The linux-calculator bc gives the results (we need this for control): echo "p=5606;b=55171;m=b*b;((b-1)^p)%m;((b+1)^p)%m" | bc 2734550616 309288627 Now calculating 55170^5606 gives a somewhat large number, but since I have to do a modulooperation, I can circumvent the usage of BigInt, I thought, because of: (a*b) % c == ((a%c) * (b%c))%c i.e. (9*7) % 5 == ((9%5) * (7%5))%5 => 63 % 5 == (4 * 2) %5 => 3 == 8 % 5 ... and a^d = a^(b+c) = a^b * a^c, therefore I can divide b+c by 2, which gives, for even or odd ds d/2 and d-(d/2), so for 8^5 I can calculate 8^2 * 8^3. So my (defective) method, which always cut's off the divisor on the fly looks like that: def powMod (b: Long, pot: Int, mod: Long) : Long = { if (pot == 1) b % mod else { val pot2 = pot/2 val pm1 = powMod (b, pot, mod) val pm2 = powMod (b, pot-pot2, mod) (pm1 * pm2) % mod } } and feeded with some values, powMod (55170, 5606, 3043839241L) res2: Long = 1885539617 powMod (55172, 5606, 3043839241L) res4: Long = 309288627 As we can see, the second result is exactly the same as the one above, but the first one looks quiet different. I'm doing a lot of such calculations, and they seem to be accurate as long as they stay in the range of Int, but I can't see any error. Using a BigInt works as well, but is way too slow: def calc2 (n: Int, pri: Long) = { val p: BigInt = pri val p3 = p * p val p1 = (p-1).pow (n) % (p3) val p2 = (p+1).pow (n) % (p3) print ("p1: " + p1 + " p2: " + p2) } calc2 (5606, 55171) p1: 2734550616 p2: 309288627 (same result as with bc) Can somebody see the error in powMod?

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  • Fastest way to calculate a 128-bit integer modulo a 64-bit integer

    - by Paul Baker
    I have a 128-bit unsigned integer A and a 64-bit unsigned integer B. What's the fastest way to calculate A % B - that is the (64-bit) remainder from dividing A by B? I'm looking to do this in either C or assembly language, but I need to target the 32-bit x86 platform. This unfortunately means that I cannot take advantage of compiler support for 128-bit integers, nor of the x64 architecture's ability to perform the required operation in a single instruction.

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  • Modulo jquery question

    - by chchrist
    Hi all, Dont ask why but I need to add class zebra to the lis with the content next to them. I do a $("li").each(function(index){ if(index%??? == 0) { } }); <ul> <li></li> <li></li> <li></li> //add here class zebra <li></li> <li></li> <li></li> <li></li> //add here class zebra <li></li> <li></li> <li></li> <li></li> //add here class zebra <li></li> </ul>

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  • Microsoft SQL 2005 - using the modulo operator

    - by cc0
    So I have a silly problem, I have not used much MSSQL before, or any SQL for that matter. I basically have a minor mathematical problem that I need solved, and I thought modulo would be good. I have a number of dates in the database, but I need them be rounded off to the closest [dynamic integer] (could be anything from 0 to 5000000) which will be input as a parameter each time this query is called. So I thought I'd use modulo to find the remainder, then subtract that remainder from the date. If there is a better way, or an integrated function, please let me know! What would be the syntax for that? I've tried a lot of things, but I keep getting error messages like integers/floats/decimals can't be used with the modulo operators. I tried casting to all kinds of numeric datatypes. Any help would be appreciated.

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  • Microsoft SQL Server 2005 - using the modulo operator

    - by cc0
    So I have a silly problem, I have not used much SQL Server before, or any SQL for that matter. I basically have a minor mathematical problem that I need solved, and I thought modulo would be good. I have a number of dates in the database, but I need them be rounded off to the closest [dynamic integer] (could be anything from 0 to 5000000) which will be input as a parameter each time this query is called. So I thought I'd use modulo to find the remainder, then subtract that remainder from the date. If there is a better way, or an integrated function, please let me know! What would be the syntax for that? I've tried a lot of things, but I keep getting error messages like integers/floats/decimals can't be used with the modulo operators. I tried casting to all kinds of numeric datatypes. Any help would be appreciated.

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  • Strange performance behaviour for 64 bit modulo operation

    - by codymanix
    The last three of these method calls take approx. double the time than the first four. The only difference is that their arguments doesn't fit in integer anymore. But should this matter? The parameter is declared to be long, so it should use long for calculation anyway. Does the modulo operation use another algorithm for numbersmaxint? I am using amd athlon64 3200+, winxp sp3 and vs2008. Stopwatch sw = new Stopwatch(); TestLong(sw, int.MaxValue - 3l); TestLong(sw, int.MaxValue - 2l); TestLong(sw, int.MaxValue - 1l); TestLong(sw, int.MaxValue); TestLong(sw, int.MaxValue + 1l); TestLong(sw, int.MaxValue + 2l); TestLong(sw, int.MaxValue + 3l); Console.ReadLine(); static void TestLong(Stopwatch sw, long num) { long n = 0; sw.Reset(); sw.Start(); for (long i = 3; i < 20000000; i++) { n += num % i; } sw.Stop(); Console.WriteLine(sw.Elapsed); } EDIT: I now tried the same with C and the issue does not occur here, all modulo operations take the same time, in release and in debug mode with and without optimizations turned on: #include "stdafx.h" #include "time.h" #include "limits.h" static void TestLong(long long num) { long long n = 0; clock_t t = clock(); for (long long i = 3; i < 20000000LL*100; i++) { n += num % i; } printf("%d - %lld\n", clock()-t, n); } int main() { printf("%i %i %i %i\n\n", sizeof (int), sizeof(long), sizeof(long long), sizeof(void*)); TestLong(3); TestLong(10); TestLong(131); TestLong(INT_MAX - 1L); TestLong(UINT_MAX +1LL); TestLong(INT_MAX + 1LL); TestLong(LLONG_MAX-1LL); getchar(); return 0; } EDIT2: Thanks for the great suggestions. I found that both .net and c (in debug as well as in release mode) does't not use atomically cpu instructions to calculate the remainder but they call a function that does. In the c program I could get the name of it which is "_allrem". It also displayed full source comments for this file so I found the information that this algorithm special cases the 32bit divisors instead of dividends which was the case in the .net application. I also found out that the performance of the c program really is only affected by the value of the divisor but not the dividend. Another test showed that the performance of the remainder function in the .net program depends on both the dividend and divisor. BTW: Even simple additions of long long values are calculated by a consecutive add and adc instructions. So even if my processor calls itself 64bit, it really isn't :( EDIT3: I now ran the c app on a windows 7 x64 edition, compiled with visual studio 2010. The funny thing is, the performance behavior stays the same, although now (I checked the assembly source) true 64 bit instructions are used.

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  • create a dataset by using modulo division method

    - by ayoom
    create a dataset with 101 integers. Use the modulo division method of hashing to store the random data values into hash tables with table sizes of 7, 51, and 151. Use the linear probing and quadratic method of collision resolution. Print out the tables after the data values have been stored. Search for 10 different values in each of the three hash tables, counting the number of comparisons necessary. Print out the number of comparisons necessary in each case, in tabular form.

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  • Floating Point Arithmetic - Modulo Operator on Double Type

    - by CrimsonX
    So I'm trying to figure out why the modulo operator is returning such a large unusual value. If I have the code: double result = 1.0d % 0.1d; it will give a result of 0.09999999999999995. I would expect a value of 0 Note this problem doesn't exist using the dividing operator - double result = 1.0d / 0.1d; will give a result of 10.0, meaning that the remainder should be 0. Let me be clear: I'm not surprised that an error exists, I'm surprised that the error is so darn large compared to the numbers at play. 0.0999 ~= 0.1 and 0.1 is on the same order of magnitude as 0.1d and only one order of magnitude away from 1.0d. Its not like you can compare it to a double.epsilon, or say "its equal if its < 0.00001 difference". I've read up on this topic on StackOverflow, in the following posts one two three, amongst others. Can anyone suggest explain why this error is so large? Any any suggestions to avoid running into the problems in the future (I know I could use decimal instead but I'm concerned about the performance of that).

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  • Fast modulo 3 or division algorithm?

    - by aaa
    Hello is there a fast algorithm, similar to power of 2, which can be used with 3, i.e. n%3. Perhaps something that uses the fact that if sum of digits is divisible by three, then the number is also divisible. This leads to a next question. What is the fast way to add digits in a number? I.e. 37 - 3 +7 - 10 I am looking for something that does not have conditionals as those tend to inhibit vectorization thanks

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  • SQL Group By Modulo of Row Count

    - by Alex Czarto
    I have the following sample data: Id Name Quantity 1 Red 1 2 Red 3 3 Blue 1 4 Red 1 5 Yellow 3 So for this example, there are a total of 5 Red, 1 Blue, and 3 Yellow. I am looking for a way to group them by Color, but with a maximum of 2 items per group (sorting is not important). Like so: Name QuantityInPackage Red 2 Red 2 Red 1 Blue 1 Yellow 2 Yellow 1 Any suggestions on how to accomplish this using T-SQL on MS-SQL 2005?

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  • Big problem with Dijkstra algorithm in a linked list graph implementation

    - by Nazgulled
    Hi, I have my graph implemented with linked lists, for both vertices and edges and that is becoming an issue for the Dijkstra algorithm. As I said on a previous question, I'm converting this code that uses an adjacency matrix to work with my graph implementation. The problem is that when I find the minimum value I get an array index. This index would have match the vertex index if the graph vertexes were stored in an array instead. And the access to the vertex would be constant. I don't have time to change my graph implementation, but I do have an hash table, indexed by a unique number (but one that does not start at 0, it's like 100090000) which is the problem I'm having. Whenever I need, I use the modulo operator to get a number between 0 and the total number of vertices. This works fine for when I need an array index from the number, but when I need the number from the array index (to access the calculated minimum distance vertex in constant time), not so much. I tried to search for how to inverse the modulo operation, like, 100090000 mod 18000 = 10000 and, 10000 invmod 18000 = 100090000 but couldn't find a way to do it. My next alternative is to build some sort of reference array where, in the example above, arr[10000] = 100090000. That would fix the problem, but would require to loop the whole graph one more time. Do I have any better/easier solution with my current graph implementation?

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  • Modulus PHP Problem

    - by Eli
    I have a problem, I am trying to calculate what the lowest prime is of a number but I do not understand the result that PHP is giving me. If I have this number $number = 600851475143; Then I modulus it: $primes = array( 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97); foreach($primes as $key=>$value) { if($number % $value == 0 ) {echo $value; break; } } Why is it that $value = 3? If $value = 3, that means that 600851475143 / 3 should be an integer, but its not. So I do not understand why that if() evaluates to true?

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  • Grails: Property Null error

    - by richardhell
    I've a domain called Modulo with some properties and a Controller with a method that create a object from model and save it, when execute save the shell show this error: La propiedad [{0}] de la clase [{1}] no puede ser nulo But if i set the constraint nullable to true, the error show again. I think that i should not set this cosntraint. The model is linked to a mysql table with all properties except id allow null. I think I am not doing something wrong here. Any advice?? Domain: Modulo class Modulo { String nombre String icon String url //static constraint = { // url(nullable:true) //} } Controller: Example class ExampleController { def index = { def modulo = new Modulo( nombre:'xxx', icon:'xxx' ) if (modulo.save()){ println 'ok' }else{ modulo.errors.allErrors.each { println it.defaultMessage} } } } Thanks. José

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  • What does the ".align" x86 Assembler directive do exactly? [migrated]

    - by Sinister Clock
    I will list exactly what I do not understand, and show you the parts I can not understand as well. First off, The .Align Directive .align integer, pad. The .align directive causes the next data generated to be aligned modulo integer bytes 1.~ ? : What is implied with "causes the next data generated to be aligned modulo integer bytes?" I can surmise that the next data generated is a memory-to-register transfer, no? Modulo would imply the remainder of a division. I do not understand "to be aligned modulo integer bytes"....... What would be a remainder of a simple data declaration, and how would the next data generated being aligned by a remainder be useful? If the next data is aligned modulo, that is saying the next generated data, whatever that means exactly, is the remainder of an integer? That makes absolutely no sense. What specifically would the .align, say, .align 8 directive issued in x86 for a data byte compiled from a C char, i.e., char CHARACTER = 0; be for? Or specifically coded directly with that directive, not preliminary Assembly code after compiling C? I have debugged in Assembly and noticed that any C/C++ data declarations, like chars, ints, floats, etc. will insert the directive .align 8 to each of them, and add other directives like .bss, .zero, .globl, .text, .Letext0, .Ltext0. What are all of these directives for, or at least my main asking? I have learned a lot of the main x86 Assembly instructions, but never was introduced or pointed at all of these strange directives. How do they affect the opcodes, and are all of them necessary?

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  • Python how to execute generate code ?

    - by Natim
    Hello guys I have this code, and I would like to use the app parameter to generate the code instead of duplicating it. if app == 'map': try: from modulo.map.views import map return map(request, *args, **kwargs) except ImportError: pass elif app == 'schedule': try: from modulo.schedule.views import schedule_day return schedule_day(request, *args, **kwargs) except ImportError: pass elif app == 'sponsors': try: from modulo.sponsors.views import sponsors return sponsors(request, *args, **kwargs) except ImportError: pass elif app == 'streaming': try: from modulo.streaming.views import streaming return streaming(request, *args, **kwargs) except ImportError: pass Do you have any idea ? Thanks

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  • Python: how to execute generated code ?

    - by Natim
    Hello guys I have this code, and I would like to use the app parameter to generate the code instead of duplicating it. if app == 'map': try: from modulo.map.views import map return map(request, *args, **kwargs) except ImportError: pass elif app == 'schedule': try: from modulo.schedule.views import schedule_day return schedule_day(request, *args, **kwargs) except ImportError: pass elif app == 'sponsors': try: from modulo.sponsors.views import sponsors return sponsors(request, *args, **kwargs) except ImportError: pass elif app == 'streaming': try: from modulo.streaming.views import streaming return streaming(request, *args, **kwargs) except ImportError: pass Do you have any idea ? Thanks

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  • How to validate a Singaporean FIN?

    - by abigblackman
    Can anyone provide an algorithm to validate a Singaporean FIN? I know with a Singaporean NRIC I can validate it via modulo 11 and then compare the result to a lookup table but cannot find a similar lookup table for the FIN. I also do not know for sure if the modulo 11 is the correct method to validate. I am aware the government sells a algorithm for $400 but maybe someone knows a cheaper way. Bonus points for c# implementation.

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  • simplify expression k/m%n

    - by aaa
    hello. Simple question, is it possible to simplify (or replace division or modulo by less-expensive operation) (k/m)%n where variables are integers and operators are C style division and modulo operators. what about the case where m and n are constants (both or just one), not based 2? Thank you

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  • Modular Reduction of Polynomials in NTRUEncrypt

    - by Neville
    Hello everyone. I'm implementing the NTRUEncrypt algorithm, according to an NTRU tutorial, a polynomial f has an inverse g such that f*g=1 mod x, basically the polynomial multiplied by its inverse reduced modulo x gives 1. I get the concept but in an example they provide, a polynomial f = -1 + X + X^2 - X4 + X6 + X9 - X10 which we will represent as the array [-1,1,1,0,-1,0,1,0,0,1,-1] has an inverse g of [1,2,0,2,2,1,0,2,1,2,0], so that when we multiply them and reduce the result modulo 3 we get 1, however when I use the NTRU algorithm for multiplying and reducing them I get -2. Here is my algorithm for multiplying them written in Java: public static int[] PolMulFun(int a[],int b[],int c[],int N,int M) { for(int k=N-1;k>=0;k--) { c[k]=0; int j=k+1; for(int i=N-1;i>=0;i--) { if(j==N) { j=0; } if(a[i]!=0 && b[j]!=0) { c[k]=(c[k]+(a[i]*b[j]))%M; } j=j+1; } } return c; } It basicall taken in polynomial a and multiplies it b, resturns teh result in c, N specifies the degree of the polynomials+1, in teh example above N=11; and M is the reuction modulo, in teh exampel above 3. Why am I getting -2 and not 1?

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  • Oracle annuncia la nuova release di Oracle Hyperion EPM System

    - by Stefano Oddone
    Lo scorso 4 Aprile, durante l'Oracle Open World tenutosi a Tokyo, Mark Hurd, Presidente di Oracle, ha annunciato l'imminente rilascio della release 11.1.2.2 di Oracle Hyperion Enterprise Performance Managent System, la piattaforma leader nel mercato mondiale dell'EPM. La nuova release introduce un insieme estremamente significativo di nuovi moduli, migliorie a moduli esistenti, evoluzioni tecnologiche e funzionali che incrementano ulteriormente il valore ed il vantaggio competitivo fornito dall'offerta Oracle. Tra le principali novità in evidenza: introduzione del nuovo modulo Oracle Hyperion Project Financial Planning, verticalizzazione per la pianificazione economico-finanziaria, il funding ed il budgeting di progetti, iniziative, attività, commesse arricchimento di Oracle Hyperion Planning con funzionalità built-in a supporto del Predictive Planning e del Rolling Forecast per supportare processi di budgeting e forecasting sempre più flessibili, frequenti ed efficaci introduzione del nuovo modulo Oracle Account Reconciliation Manager per la gestione dell'intero ciclo di vita delle attività di riconciliazione dei conti tra General Ledger e Sub-Ledger o tra sistemi contabili differenti arricchimento di Oracle Hyperion Financial Management con un'interfaccia web totalmente nuova e l'introduzione della Smart Dimensionality, ovvero la possibilità di definire modelli con più delle 12 dimensioni "canoniche" tipiche delle releases precedenti, con una gestione ottimizzata di query e calcoli in funzione della cardinalità delle dimensioni in gioco arricchimento di Oracle Hyperion Profitability & Cost Management con funzionalità di Detailed Profitability, ovvero la possibilità di implementare modelli di costing e profittabilità in presenza di dimensioni ad altissima cardinalità quali, ad esempio, gli SKU delle industrie Retail e Distribution, i clienti delle Banche Retail e delle Telco, le singole utente delle Utilities. arricchimento di Oracle Hyperion Financial Data Quality Management, in particolare della componente ERP Integrator, con estensione delle integrazioni pre-built verso SAP Financials e JD Edwards Enterprise One Financials introduzione di Oracle Exalytics, il primo engineered system specificatamente progettato per l'In-Memory Analytics che permette di ottenere performance di calcolo e di analisi senza precedenti al crescere dei volumi di dati, delle dimensioni dei modelli e della concorrenza degli utenti, supportando così processi di Business Intelligence, Planning & Budgeting, Cost Allocation sempre più articolati e distribuiti Il prossimo 19 Aprile nella sede Oracle di Cinisello Balsamo (MI) si terrà un evento dove verranno presentate in dettaglio le novità introdotte dalla nuova release dell'EPM System; l'evento sarà replicato il 3 Maggio nella sede Oracle di Roma. L'evento è pubblico e gratuito, chi fosse interessato può registrarsi qui. Per ulteriori informazioni potete fare riferimento alla Press Release Ufficiale Qui potete rivedere l'intervento di Mark Hurd all'Open World sulla Strategia Oracle per il Business Analytics

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