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  • Speeding up Math calculations in Java

    - by Simon
    I have a neural network written in Java which uses a sigmoid transfer function defined as follows: private static double sigmoid(double x) { return 1 / (1 + Math.exp(-x)); } and this is called many times during training and computation using the network. Is there any way of speeding this up? It's not that it's slow, it's just that it is used a lot, so a small optimisation here would be a big overall gain.

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  • C# Int and math not returning full value.

    - by Mike
    Int64 c1 = Convert.ToInt64(csvdeep[1]); Int64 division = 1024; string results = Math.Abs(c1 / division / division / division).ToString(); My c1 is 10201841664 and results is "9". I'd perfer to get the 2nd two decimal places so my real result would be 9.50. Any tips on how I could get the 2 decimal places?

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  • toFixed(2) - math round ?

    - by adrien334
    Hi, I would like to find a function that will return this kind of formatted values : 1.5555 => 1.55 1.5556 => 1.56 1.5554 => 1.55 1.5651 => 1.56 toFixed() and math round return this value : 1.5651.fixedTo(2) => 1.57 This will be usefull for money rounding.

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  • Raphael JS image animation performance.

    - by michael
    Hi, I'm trying to create an image animation using Raphael JS. I want the effect of a bee moving randomly across the page, I've got a working example but it's a bit "jittery", and I'm getting this warning in the console: "Resource interpreted as image but transferred with MIME type text/html" I'm not sure if the warning is causing the "jittery" movement or its just the way I approached it using maths. If anyone has a better way to create the effect, or improvements please let me know. I have a demo online here and heres my javascript code: function random(min, max) { return Math.floor(Math.random() * (max - min + 1)) + min; } function BEE(x, y, scale) { this.x = x; this.y = y; this.s = scale; this.paper = Raphael("head", 915, 250); this.draw = function() { this.paper.clear(); this.paper.image("bee.png", this.x, this.y, 159*this.s, 217*this.s); } this.update = function() { var deg = random(-25, 25); var newX = Math.cos(Raphael.rad(deg)) * 2; var newY = Math.sin(Raphael.rad(deg)) * 2; this.x += newX; this.y += newY; if( this.x > 915) { this.x = 0; } if( this.y > 250 || this.y < 0 ) { this.y = 125; } } } $(document).ready(function() { var bee = new BEE(100, 150, 0.4); var timer = setInterval(function(){ bee.draw(); bee.update(); }, 15); }

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  • What is the name of this geometrical function?

    - by Spike
    In a two dimentional integer space, you have two points, A and B. This function returns an enumeration of the points in the quadrilateral subset bounded by A and B. A = {1,1} B = {2,3} Fn(A,B) = {{1,1},{1,2},{1,3},{2,1},{2,2},{2,3}} I can implement it in a few lines of LINQ. private void UnknownFunction(Point to, Point from, List<Point> list) { var vectorX = Enumerable.Range(Math.Min(to.X, from.X), Math.Abs(to.X - from.Y) + 1); var vectorY = Enumerable.Range(Math.Min(to.Y, from.Y), Math.Abs(to.Y - from.Y) + 1); foreach (var x in vectorX) foreach (var y in vectorY) list.Add(new Point(x, y)); } I'm fairly sure that this is a standard mathematical operation, but I can't think what it is. Feel free to tell me that it's one line of code in your language of choice. Or to give me a cunning implementation with lambdas or some such. But mostly I just want to know what it's called. It's driving me nuts. It feels a little like a convolution, but it's been too long since I was at school for me to be sure.

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  • How to check if a number is a power of 2

    - by configurator
    Today I needed a simple algorithm for checking if a number is a power of 2. The algorithm needs to be: Simple Correct for any ulong value. I came up with this simple algorithm: private bool IsPowerOfTwo(ulong number) { if (number == 0) return false; for (ulong power = 1; power > 0; power = power << 1) { // this for loop used shifting for powers of 2, meaning // that the value will become 0 after the last shift // (from binary 1000...0000 to 0000...0000) then, the for // loop will break out if (power == number) return true; if (power > number) return false; } return false; } But then I thought, how about checking if log2x is an exactly round number? But when I checked for 2^63+1, Math.Log returned exactly 63 because of rounding. So I checked if 2 to the power 63 is equal to the original number - and it is, because the calculation is done in doubles and not in exact numbers: private bool IsPowerOfTwo_2(ulong number) { double log = Math.Log(number, 2); double pow = Math.Pow(2, Math.Round(log)); return pow == number; } This returned true for the given wrong value: 9223372036854775809. Does anyone have any suggestion for a better algorithm?

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  • The best cross platform (portable) arbitrary precision math library

    - by Siu Ching Pong - Asuka Kenji
    Dear ninjas / hackers / wizards, I'm looking for a good arbitrary precision math library in C or C++. Could you please give me some advices / suggestions? The primary requirements: It MUST handle arbitrarily big integers (my primary interest is on integers). In case that you don't know what the word arbitrarily big means, imagine something like 100000! (the factorial of 100000). The precision MUST NOT NEED to be specified during library initialization / object creation. The precision should ONLY be constrained by the available resources of the system. It SHOULD utilize the full power of the platform, and should handle "small" numbers natively. That means on a 64-bit platform, calculating 2^33 + 2^32 should use the available 64-bit CPU instructions. The library SHOULD NOT calculate this in the same way as it does with 2^66 + 2^65 on the same platform. It MUST handle addition (+), subtraction (-), multiplication (*), integer division (/), remainder (%), power (**), increment (++), decrement (--), gcd(), factorial(), and other common integer arithmetic calculations efficiently. Ability to handle functions like sqrt() (square root), log() (logarithm) that do not produce integer results is a plus. Ability to handle symbolic computations is even better. Here are what I found so far: Java's BigInteger and BigDecimal class: I have been using these so far. I have read the source code, but I don't understand the math underneath. It may be based on theories / algorithms that I have never learnt. The built-in integer type or in core libraries of bc / Python / Ruby / Haskell / Lisp / Erlang / OCaml / PHP / some other languages: I have ever used some of these, but I have no idea on which library they are using, or which kind of implementation they are using. What I have already known: Using a char as a decimal digit, and a char* as a decimal string and do calculations on the digits using a for-loop. Using an int (or a long int, or a long long) as a basic "unit" and an array of it as an arbitrary long integer, and do calculations on the elements using a for-loop. Booth's multiplication algorithm What I don't know: Printing the binary array mentioned above in decimal without using naive methods. Example of a naive method: (1) add the bits from the lowest to the highest: 1, 2, 4, 8, 16, 32, ... (2) use a char* string mentioned above to store the intermediate decimal results). What I appreciate: Good comparisons on GMP, MPFR, decNumber (or other libraries that are good in your opinion). Good suggestions on books / articles that I should read. For example, an illustration with figures on how a un-naive arbitrarily long binary to decimal conversion algorithm works is good. Any help. Please DO NOT answer this question if: you think using a double (or a long double, or a long long double) can solve this problem easily. If you do think so, it means that you don't understand the issue under discussion. you have no experience on arbitrary precision mathematics. Thank you in advance! Asuka Kenji

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  • Handling inverse kinematics: animation blending or math?

    - by meds
    I've been working for the past four days on inverse kinematics for my game engine. I'm working on a game with a shoestring budget so when the idea of inverse kinematics came up I knew I had to make it such that the 3D models bones would be mathematically changed to appear to be stepping on objects. This is causing some serious problems with my animation, after it was technically implemented the animations started looking quite bad when the character was wlaking up inclines or steps even though mathematically the stepping was correct and was even smoothly interpolating. So I was wondering, is it actually possible to get a smooth efficient inverse kinematic system based exclusively on math where bones are changed or is this just a wild goose chase and I should either solve the inverse kinematics problem with animation blending or don't do it at all?

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  • Perl Math::Business::EMA help

    - by Dustin
    Script pulls data from mysql: $DBI::result = $db->prepare(qq{ SELECT close FROM $table WHERE day <= '$DATE' ORDER BY day DESC LIMIT $EMA }); $DBI::result->execute(); while($row = $DBI::result->fetchrow) { print "$row\n"; }; with the following example results: 1.560 1.560 1.550... But I need to work out the EMA using Math::Business::EMA; and I'm not sure how to calculate this while maintaining the accuracy. EMA is weighted and My lack of Perl knowledge is not helping.

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  • Wordpress comments - perform simple math?

    - by RodeoRamsey
    I have a Wordpress website in which one of the categories I've stripped the comments field down to basic whole numbers only. The logged in user can enter data on the post via the "comments" field, in basic simple whole numbers. Is there any way to take the MOST RECENT comment on all posts from that category (cat 1) and run basic math? My goal is to take the most recent comment's input from each post and add it together and display it via some php/html on another page/post or widget somewhere. Thanks!

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  • Mathematics for AI/Machine learning ?

    - by Ankur Gupta
    I intend to build a simple recommendation systems for fun. I read a little on the net and figured being good at math would enable on to build a good recommendation system. My math skills are not good. I am willing to put considerable efforts and time in learning maths. Can you please tell me what mathematics topics should I cover? Also if any of you folks can point me to some online material to learn from it would be great. I am aware of MIT OCW, book like collective intelligence. Math Topics to cover and from where to read would really help.

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  • Pythagoras triangle

    - by Gogolo
    I would like to ask you about this programing part, is it everything ok? the task was: Write the pseudocode or flow diagram and code for the theorem of Pythagoras - for right-angle triangle with three ribs (a, b, and c) of type integer int KendiA = 0; int KendiB = 0; int H = 0; string Trekendeshi = null; int gjetja = 0; for (KendiA = 1; KendiA <= 15; KendiA++) { for (KendiB = 1; KendiB <= 15; KendiB++) { for (H = 1; H <= 30; H++) { if ((Math.Pow(KendiA, 2) + Math.Pow(KendiB, 2) == Math.Pow(H, 2))) { gjetja = gjetja + 1; Trekendeshi = gjetja + "\t" + KendiA + "\t" + KendiB + "\t" + H; Console.WriteLine(Trekendeshi); } } } }

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  • python geometry help

    - by Enriquev
    Hello, I have the following problem, I am trying to find the following distances (F1 and F2): This is what I have as of now: def FindArrow(self, X1, Y1, X2, Y2, X3, Y3): self.X1 = float(X1) self.Y1 = float(Y1) self.X2 = float(X2) self.Y2 = float(Y2) self.X3 = float(X3) self.Y3 = float(Y3) #center coords of the circle self.Xc = None self.Yc = None #radius self.R = None #F1 and F2 self.FAB = None self.FBC = None #check if the coordinates are collinear invalide = self.X1 * (self.Y2 - self.Y3) + self.X2 * (self.Y3 - self.Y1) + self.X3 * (self.Y1 - self.Y2) if (invalide == 0): return #get the coords of the circle's center s = (0.5 * ((self.X2 - self.X3)*(self.X1 - self.X3) - (self.Y2 - self.Y3) * (self.Y3 - self.Y1))) / invalide self.Xc = 0.5 * (self.X1 + self.X2) + s * (self.Y2 - self.Y1) self.Yc = 0.5 * (self.Y1 + self.Y2) + s * (self.X1 - self.X2) #get the radius self.R = math.sqrt(math.pow(self.Xc - self.X1, 2) + math.pow(self.Yc - self.Y1, 2)) Until here everything seems to work, now what would be the next steps to get F1 and F2 ?

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  • Exponential volume control with a specified midpoint

    - by Lars
    I have a slider that returns values from 0 to 100. I am using this to control the gain of an oscillator. When the slider is at 0, I would like the gain to be 0.0 When the slider is at 50, I would like the gain to be 0.1 When the slider is at 100, I would like the gain to be 0.5 So I need to find an equation to get a smooth curve which passes through all of these points. I've got the following equation which gives an exponential curve and gets the start and end points correct, but I don't know how to force the curve through the middle point. Can anyone help? function logSlider(position){ var minP = 0; var maxP = 100; var minV = Math.log(0.0001); var maxV = Math.log(0.5); var scale = (maxV - minV) / (maxP - minP); return Math.exp(minV + scale*(position-minP)); }

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  • C program giving incorrect output for simple math!

    - by DuffDuff
    (all are declared as ints, none are initialized to anything beforehand. I have included math.h and am compiling with -lm) cachesize = atoi(argv[1]); blocksize = atoi(argv[3]); setnumber = (cachesize/blocksize); printf("setnumber: %d\n", setnumber); setbits = (log(setnumber))/(log(2)); printf("sbits: %d\n", setbits); when given cachesize as 1024 and blocksize as 16 the output is as follows: setnumber: 64 sbits: 5 but log(64)/log(2) = 6 ! It works correctly when given cachesize 512 and blocksize 32. I can't seem to win. I'm really hoping that it's a stupid mistake on my part, and I'd be grateful if anyone could point out what it is! Thank you! PS: I posted this in Yahoo Answers first but that was probably silly. Won't be doing that again.

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  • PHP preg_match Math Function

    - by Matt
    I'm writing a script that will allow a user to input a string that is a math statement, to then be evaluated. I however have hit a roadblock. I cannot figure out how, using preg_match, to dissallow statements that have variables in them. Using this, $calc = create_function("", "return (" . $string . ");" ); $calc();, allows users to input a string that will be evaluated, but it crashes whenever something like echo 'foo'; is put in place of the variable $string.

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  • Simple Java math operations

    - by user1730056
    I'm making a BMI calculator that doesn't seem to be working. The math operations work if i just do something like w/h, but once i had the brackets, it returns an error. If i change the variables w and h and use a constant number, the operation works. Another problem is that although i'm making result a double, it seems to be rounding to the nearest int. Could someone tell me what I'm doing wrong here? public class ass10 { public static void main(String[] args) { bmi(223,100); } public static bmi(int w, int h){ double result; result = (w/(h*h))*703 System.out.println(result) } }

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  • Can i use a switch to hold a function?

    - by TIMOTHY
    I have a 3 file program, basically teaching myself c++. I have an issue. I made a switch to use the math function. I need and put it in a variable, but for some reason I get a zero as a result. Also another issue, when I select 4 (divide) it crashes... Is there a reason? Main file: #include <iostream> #include "math.h" #include <string> using namespace std; int opersel; int c; int a; int b; string test; int main(){ cout << "Welcome to Math-matrix v.34"<< endl; cout << "Shall we begin?" <<endl; //ASK USER IF THEY ARE READY TO BEGIN string answer; cin >> answer; if(answer == "yes" || answer == "YES" || answer == "Yes") { cout << "excellent lets begin..." << endl; cout << "please select a operator..." << endl << endl; cout << "(1) + " << endl; cout << "(2) - " << endl; cout << "(3) * " << endl; cout << "(4) / " << endl; cin >> opersel; switch(opersel){ case 1: c = add(a,b); break; case 2: c = sub(a,b); break; case 3: c = multi(a,b); break; case 4: c = divide(a,b); break; default: cout << "error... retry" << endl; }// end retry cout << "alright, how please select first digit?" << endl; cin >> a; cout << "excellent... and your second?" << endl; cin >> b; cout << c; cin >> test; }else if (answer == "no" || answer == "NO" || answer == "No"){ }//GAME ENDS }// end of int main Here is my math.h file #ifndef MATH_H #define MATH_H int add(int a, int b); int sub(int a, int b); int multi(int a, int b); int divide(int a, int b); #endif Here is my math.cpp: int add(int a, int b) { return a + b; } int sub(int a, int b) { return a - b; } int multi(int a, int b) { return a * b; } int divide(int a, int b) { return a / b; } }// end of int main

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  • Unable to find reference to std library math function inside library

    - by Alex Marshall
    Hello, I've got several programs that use shared libraries. Those shared libraries in turn use various standard C libraries. ie Program A and Program B both use Shared Library S. Shared Library S uses std C math. I want to be able to statically link Shared Library S against the standard library, and then statically link Programs A and B against S so that I don't have to be dragging around the library files, because these programs are going to be running on an embedded system running BusyBox 0.61. However, when I try to statically link the programs against Shared Library S, I get an error message from GCC stating : ../lib/libgainscalecalc.a(gainscalecalc.): In function 'float2gs': [path to my C file].c:73: undefined reference to 'log' Can somebody please help me out ? The make commands I'm using are below : CFLAGS += -Wall -g -W INCFLAGS = -I$(CROSS_INCLUDE)/usr/include LIBFLAGS += -L$(CROSS_LIB)/usr/lib -lm gainscalecalc_static.o: gainscalecalc.c $(CC) $(CFLAGS) -c $< -I. $(INCFLAGS) -o $@ gainscalecalc_dynamic.o: gainscalecalc.c $(CC) $(CFLAGS) -fPIC -c $< -o $@ all: staticlib dynamiclib static_driver dynamic_driver clean: $(RM) *.o *.a *.so *~ driver core $(OBJDIR) static_driver: driver.c staticlib $(CC) $(CFLAGS) -static driver.c $(INCFLAGS) $(LIBFLAGS) -I. -L. -lgainscalecalc -o $@ dynamic_driver: driver.c dynamiclib $(CC) $(CFLAGS) driver.c -o $@ -L. -lgainscalecalc staticlib: gainscalecalc_static.o $(AR) $(ARFLAGS) libgainscalecalc.a gainscalecalc_static.o $(RANLIB) libgainscalecalc.a chmod 777 libgainscalecalc.a dynamiclib: gainscalecalc_dynamic.o $(CC) -shared -o libgainscalecalc.so gainscalecalc_dynamic.o chmod 777 libgainscalecalc.so Edit: Linking against the shared libraries compiles fine, I just haven't tested them out yet

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  • System.Math.Round bug?

    - by Jeevan
    Hi All, I was writing a function for rounding a number to two places. And I found a bug when I was trying to round specific values. So, I ran the code: class Program { static void Main(string[] args) { int limit = 100; for (int number = 0; number <= limit; number++) { Console.WriteLine((System.Math.Round((double)(number+0.995),2,MidpointRounding.AwayFromZero))); } } } And I found that: 8.99 9.99 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 32.99 33.99 34.99 35.99 36.99 37.99 38.99 39.99 numbers are not rounded to their next value. When I run the same code till 1500: I get the numbers: 8.99 9.99 32.99 33.99 34.99 35.99 36.99 37.99 38.99 39.99 1024.99 1025.99 1026.99 1027.99 1028.99 1029.99 1030.99 1031.99 1032.99 1033.99 1034.99 1035.99 1036.99 1037.99 1038.99 1039.99 1040.99 1041.99 1042.99 1043.99 1044.99 1045.99 1046.99 1047.99 1048.99 1049.99 1050.99 1051.99 1052.99 1053.99 1054.99 1055.99 1056.99 1057.99 1058.99 1059.99 1060.99 1061.99 1062.99 1063.99 1064.99 1065.99 1066.99 1067.99 1068.99 1069.99 1070.99 1071.99 1072.99 1073.99 1074.99 1075.99 1076.99 1077.99 1078.99 1079.99 1080.99 1081.99 1082.99 1083.99 1084.99 1085.99 1086.99 1087.99 1088.99 1089.99 1090.99 1091.99 1092.99 1093.99 1094.99 1095.99 1096.99 1097.99 1098.99 1099.99 1100.99 1101.99 1102.99 1103.99 1104.99 1105.99 1106.99 1107.99 1108.99 1109.99 1110.99 1111.99 1112.99 1113.99 1114.99 1115.99 1116.99 1117.99 1118.99 1119.99 1120.99 1121.99 1122.99 1123.99 1124.99 1125.99 1126.99 1127.99 1128.99 1129.99 1130.99 1131.99 1132.99 1133.99 1134.99 1135.99 1136.99 1137.99 1138.99 1139.99 1140.99 1141.99 1142.99 1143.99 1144.99 1145.99 1146.99 1147.99 1148.99 1149.99 1150.99 1151.99 1152.99 1153.99 1154.99 1155.99 1156.99 1157.99 1158.99 1159.99 1160.99 1161.99 1162.99 1163.99 1164.99 1165.99 1166.99 1167.99 1168.99 1169.99 1170.99 1171.99 1172.99 1173.99 1174.99 1175.99 1176.99 1177.99 1178.99 1179.99 1180.99 1181.99 1182.99 1183.99 1184.99 1185.99 1186.99 1187.99 1188.99 1189.99 1190.99 1191.99 1192.99 1193.99 1194.99 1195.99 1196.99 1197.99 1198.99 1199.99 1200.99 1201.99 1202.99 1203.99 1204.99 1205.99 1206.99 1207.99 1208.99 1209.99 1210.99 1211.99 1212.99 1213.99 1214.99 1215.99 1216.99 1217.99 1218.99 1219.99 1220.99 1221.99 1222.99 1223.99 1224.99 1225.99 1226.99 1227.99 1228.99 1229.99 1230.99 1231.99 1232.99 1233.99 1234.99 1235.99 1236.99 1237.99 1238.99 1239.99 1240.99 1241.99 1242.99 1243.99 1244.99 1245.99 1246.99 1247.99 1248.99 1249.99 1250.99 1251.99 1252.99 1253.99 1254.99 1255.99 1256.99 1257.99 1258.99 1259.99 1260.99 1261.99 1262.99 1263.99 1264.99 1265.99 1266.99 1267.99 1268.99 1269.99 1270.99 1271.99 1272.99 1273.99 1274.99 1275.99 1276.99 1277.99 1278.99 1279.99 1280.99 1281.99 1282.99 1283.99 1284.99 1285.99 1286.99 1287.99 1288.99 1289.99 1290.99 1291.99 1292.99 1293.99 1294.99 1295.99 1296.99 1297.99 1298.99 1299.99 1300.99 1301.99 1302.99 1303.99 1304.99 1305.99 1306.99 1307.99 1308.99 1309.99 which are not rounded to next number! Has anyone any idea about why its happening for these specific numbers!

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  • Javascript functions Math.round(num) vs num.toFixed(0) and browser inconsistencies

    - by eft
    Edit: To clarify, the problem is how to round a number to the nearest integer. i.e. 0.5 should round to 1 and 2.5 shoud round to 3. Consider the following code: <html><head></head><body style="font-family:courier"> <script> for (var i=0;i<3;i++){ var num = i + 0.50; var output = num + " " + Math.round(num) + " " + num.toFixed(0); var node = document.createTextNode(output); var pElement = document.createElement("p"); pElement.appendChild(node); document.body.appendChild(pElement); } </script> </body></html> In Opera 9.63 I get: 0.5 1 0 1.5 2 2 2.5 3 2 In FF 3.03 I get: 0.5 1 1 1.5 2 2 2.5 3 3 In IE 7 I get: 0.5 1 0 1.5 2 2 2.5 3 3 Note the bolded results. Does this mean that toFixed(0) should be avoided?

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  • Generate syntax tree for simple math operations

    - by M28
    I am trying to generate a syntax tree, for a given string with simple math operators (+, -, *, /, and parenthesis). Given the string "1 + 2 * 3": It should return an array like this: ["+", [1, ["*", [2,3] ] ] ] I made a function to transform "1 + 2 * 3" in [1,"+",2,"*",3]. The problem is: I have no idea to give priority to certain operations. My code is: function isNumber(ch){ switch (ch) { case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': case '.': return true; break; default: return false; break; } } function generateSyntaxTree(text){ if (typeof text != 'string') return []; var code = text.replace(new RegExp("[ \t\r\n\v\f]", "gm"), ""); var codeArray = []; var syntaxTree = []; // Put it in its on scope (function(){ var lastPos = 0; var wasNum = false; for (var i = 0; i < code.length; i++) { var cChar = code[i]; if (isNumber(cChar)) { if (!wasNum) { if (i != 0) { codeArray.push(code.slice(lastPos, i)); } lastPos = i; wasNum = true; } } else { if (wasNum) { var n = Number(code.slice(lastPos, i)); if (isNaN(n)) { throw new Error("Invalid Number"); return []; } else { codeArray.push(n); } wasNum = false; lastPos = i; } } } if (wasNum) { var n = Number(code.slice(lastPos, code.length)); if (isNaN(n)) { throw new Error("Invalid Number"); return []; } else { codeArray.push(n); } } })(); // At this moment, codeArray = [1,"+",2,"*",3] return syntaxTree; } alert('Returned: ' + generateSyntaxTree("1 + 2 * 3"));

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  • java.math.BigInteger pow(exponent) question

    - by Jan Kraus
    Hi, I did some tests on pow(exponent) method. Unfortunately, my math skills are not strong enough to handle the following problem. I'm using this code: BigInteger.valueOf(2).pow(var); Results: var | time in ms 2000000 | 11450 2500000 | 12471 3000000 | 22379 3500000 | 32147 4000000 | 46270 4500000 | 31459 5000000 | 49922 See? 2,500,000 exponent is calculated almost as fast as 2,000,000. 4,500,000 is calculated much faster then 4,000,000. Why is that? To give you some help, here's the original implementation of BigInteger.pow(exponent): public BigInteger pow(int exponent) { if (exponent < 0) throw new ArithmeticException("Negative exponent"); if (signum==0) return (exponent==0 ? ONE : this); // Perform exponentiation using repeated squaring trick int newSign = (signum<0 && (exponent&1)==1 ? -1 : 1); int[] baseToPow2 = this.mag; int[] result = {1}; while (exponent != 0) { if ((exponent & 1)==1) { result = multiplyToLen(result, result.length, baseToPow2, baseToPow2.length, null); result = trustedStripLeadingZeroInts(result); } if ((exponent >>>= 1) != 0) { baseToPow2 = squareToLen(baseToPow2, baseToPow2.length, null); baseToPow2 = trustedStripLeadingZeroInts(baseToPow2); } } return new BigInteger(result, newSign); }

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  • Missing Coordinates. Basic Trigonometry Help.

    - by TheDarkIn1978
    please refer to my quick diagram attached below. what i'm trying to do is get the coordinates of the yellow dots by using the angle from the red dots' known coordinates. assuming each yellow dot is about 20 pixels away from the x:50/y:250 red dot at a right angle (i think that's what it's called) how do i get their coordinates? i believe this is very basic trigonometry and i should use Math.tan(), but they didn't teach us much math in art school.

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