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Search found 379 results on 16 pages for 'euler angles'.

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• Easy way to keeping angles between -179 and 180 degrees

  - by User1

  Is there an easy way to convert an angle (in degrees) to be between -179 and 180? I'm sure I could use mod (%) and some if statements, but it gets ugly: //Make angle between 0 and 360 angle%=360; //Make angle between -179 and 180 if (angle180) angle-=360; It just seems like there should be a simple math operation that will do both statements at the same time. I may just have to create a static method for the conversion for now.

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• Encrypt text using a number

  - by Adam Matan

  Project Euler I have recently begun to solve some of the Project Euler riddles. I found the discussion forum in the site a bit frustrating (most of the discussions are closed and poorly-threaded), So I have decided to publish my Python solutions on launchpad for discussion. The problem is that it seems quite unethical to publish these solutions, as it would let other people gain reputation without doing the programming work, which the site deeply discourages. My Encryption problem I want to encrypt my answers so that only those who have already solved the riddles can see my code. The logical key would be the answer to the riddle, which is always numeric. In order to prevent brute-force attacks on my answers, I want to find an encryption algorithm that takes a significantly long time (few seconds) to run. Do you know any such algorithm? I would fancy a Python package, which I can attach to the code, over an external program that might have portability issues. Thanks, Adam

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• More ruby-like solution to this problem?

  - by RaouL

  I am learning ruby and practicing it by solving problems from Project Euler. This is my solution for problem 12. # Project Euler problem: 12 # What is the value of the first triangle number to have over five hundred divisors? require 'prime' triangle_number = ->(num){ (num *(num + 1)) / 2 } factor_count = ->(num) do prime_fac = Prime.prime_division(num) exponents = prime_fac.collect { |item| item.last + 1 } fac_count = exponents.inject(:*) end n = 2 loop do tn = triangle_number.(n) if factor_count.(tn) >= 500 puts tn break end n += 1 end Any improvements that can be made to this piece of code?

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• How much time should it take to find the sum of all prime numbers less than 2 million?

  - by Shahensha

  I was trying to solve this Project Euler Question. I implemented the sieve of euler as a helper class in java. It works pretty well for the small numbers. But when I input 2 million as the limit it doesn't return the answer. I use Netbeans IDE. I waited for a lot many hours once, but it still didn't print the answer. When I stopped running the code, it gave the following result Java Result: 2147483647 BUILD SUCCESSFUL (total time: 2,097 minutes 43 seconds) This answer is incorrect. Even after waiting for so much time, this isn't correct. While the same code returns correct answers for smaller limits. Sieve of euler has a very simple algo given at the botton of this page. My implementation is this: package support; import java.util.ArrayList; import java.util.List; /** * * @author admin */ public class SieveOfEuler { int upperLimit; List<Integer> primeNumbers; public SieveOfEuler(int upperLimit){ this.upperLimit = upperLimit; primeNumbers = new ArrayList<Integer>(); for(int i = 2 ; i <= upperLimit ; i++) primeNumbers.add(i); generatePrimes(); } private void generatePrimes(){ int currentPrimeIndex = 0; int currentPrime = 2; while(currentPrime <= Math.sqrt(upperLimit)){ ArrayList<Integer> toBeRemoved = new ArrayList<Integer>(); for(int i = currentPrimeIndex ; i < primeNumbers.size() ; i++){ int multiplier = primeNumbers.get(i); toBeRemoved.add(currentPrime * multiplier); } for(Integer i : toBeRemoved){ primeNumbers.remove(i); } currentPrimeIndex++; currentPrime = primeNumbers.get(currentPrimeIndex); } } public List getPrimes(){ return primeNumbers; } public void displayPrimes(){ for(double i : primeNumbers) System.out.println(i); } } I am perplexed! My questions is 1) Why is it taking so much time? Is there something wrong in what I am doing? Please suggest ways for improving my coding style, if you find something wrong.

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• converting string euler number to int in c#

  - by Howlingfish

  i have an account number that is stored in as a query string. How do i convert 6.21129e+006 into an actual int

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• Small but hard programming tasks (Complete apps as opposed to Euler)

  - by dotnetdev

  I have a bit of free time at work and was wondering, what are some hard applications to build but which are not big? Hopefully nothing which requires specialist knowledge but something nonetheless hard and which will boost my coding/problem-solving skills. Thanks

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• Euler rotation of direction vector

  - by Tom Savage

  I have defined an object in 3D space with position, rotation and scale values (all defined as 3D vectors). It also has upwards and forwards direction vectors. When I rotate the object, I need these direction vectors to rotate with it. Assuming my up vector is (0, 1, 0) and my forwards vector is (0, 0, 1) at zero rotation, how might I achieve this?

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• Convert rotation from Right handed System to left handed

  - by Hector Llanos

  I have Euler angles from a right handed system that I am trying to convert to a left handed system. All the information that I have read online says that to convert it simply multiply the axis and the angle in the correct order and it should work. In other words, Z * Y * X. When I do this what I see in Maya, and in engine still do not match up. This is what I have so far: static Quaternion ConvertToRightHand(Vector3 Euler) { Quaternion x = Quaternion.AngleAxis(-Euler.x, Vector3.right); Quaternion y = Quaternion.AngleAxis(Euler.y, Vector3.up); Quaternion z = Quaternion.AngleAxis(Euler.z, Vector3.forward); return (z * y * x); } Keeping the -Euler.x helps keep the object pointing up correctly, but when I pass ( 0,0,0) to face in the -z, it faces in the +z. Help :/

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• Where do you go to tickle your brain (to get programming challenges)?

  - by Prakash

  I am sure we all have some place to go to get our brain teased! Sometimes i visit Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems Where do you all go?

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• How do I break out of a loop in Scala?

  - by TiansHUo

  For Problem 4 of Project Euler How do I break out a loop? var largest=0 for(i<-999 to 1 by -1) { for (j<-i to 1 by -1) { val product=i*j if (largest>product) // I want to break out here else if(product.toString=product.toString.reverse) largest=largest max product } } And does anyone know how to turn nested for loops into tail recursion?

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• How many integers 0 < n < 10E18 have the property that the sum of the digits of n equals the sum of digits of 137n?

  - by Allen

  I'm stumped on a project Euler question, #290. Can anybody point me in the right direction? i = 0 o = 0 p = 1 while i < 10 ** 18 j = i.to_s.split('').map(&:to_i) k = j.inject(:+) l = 137 * i m = l.to_s.split('').map(&:to_i) n = m.inject(:+) if k == n o += 1 end if i == (9 * 10 ** p) * (10 ** p) i += 18 p += 1 o += 1 else i += 9 end end puts o

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• Algorithm question.

  - by Lukasz Lew

  I can't solve it: You are given 8 integers: A, B, C representing a line on a plane with equation A*x + B*y = C a, b, c representing another line x, y representing a point on a plane The two lines are not parallel therefore divide plane into 4 pieces. Point (x, y) lies inside of one these pieces. Problem: Write a fast algorithm that will find a point with integer coordinates in the same piece as (x,y) that is closest to the cross point of the two given lines. Note: This is not a homework, this is old Euler-type task that I have absolutely no idea how to approach.

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• Why is Java not telling me when I can't use Integer?

  - by Sebi

  For a small project (Problem 10 Project Euler) i tried to sum up all prime numbers below 2 millions. So I used a brute force method and iterated from 0 to 2'000'000 and checked if the number is a prime. If it is I added it to the sum: private int sum = 0; private void calculate() { for (int i = 0; i < 2000000; i++) { if (i.isPrime()) { sum = sum + i; } } sysout(sum) } The result of this calculation is 1179908154, but this is incorrect. So i changed int to BigInteger and now i get the correct sum 142913828922. Obviously the range of int was overflowed. But why can't Java tell my that? (e.g. by an exception)

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• Fastest way to list all primes below N in python

  - by jbochi

  This is the best algorithm I could come up with after struggling with a couple of Project Euler's questions. def get_primes(n): numbers = set(range(n, 1, -1)) primes = [] while numbers: p = numbers.pop() primes.append(p) numbers.difference_update(set(range(p*2, n+1, p))) return primes >>> timeit.Timer(stmt='get_primes.get_primes(1000000)', setup='import get_primes').timeit(1) 1.1499958793645562 Can it be made even faster? EDIT: This code has a flaw: Since numbers is an unordered set, there is no guarantee that numbers.pop() will remove the lowest number from the set. Nevertheless, it works (at least for me) for some input numbers: >>> sum(get_primes(2000000)) 142913828922L #That's the correct sum of all numbers below 2 million >>> 529 in get_primes(1000) False >>> 529 in get_primes(530) True EDIT: The rank so far (pure python, no external sources, all primes below 1 million): Sundaram's Sieve implementation by myself: 327ms Daniel's Sieve: 435ms Alex's recipe from Cookbok: 710ms EDIT: ~unutbu is leading the race.

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• How to change handedness of coordinates?

  - by 742

  How to convert from Euler's coordinates E1 = (x1, y1, z1, yaw1, pitch1, roll1) to E2 = (x2, y2, z2, yaw2, pitch2, roll2) where x, y, z are the coordinates of a point and yaw, pitch, roll the direction/orientation of a vector which origin is the point. yaw is around y, pitch around x, roll around z. They are performed in that order. Yaw 0 is normal to the plan xy (opposite to z in E1 and equal to z in E2). E1 uses a right handed space and E2 a left handed space. Both have the same origin, the same direction for y (top) and z (into the screen). They differ by x which is to the left on E1 and to the right on E2. They also differ by their direction of positive rotations. I've a custom type to hold the scalar representation and to convert from and to the equivalent WPF Matrix3d representation.

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• Fibonacci Sequence using loop and recur

  - by AdamJMTech

  I am doing the Project Euler challenge in Clojure and I want to find the sum of all the even numbers in a fibonacci sequence up to a certain number. The code for a function that does this is below. I know there are quicker and easier ways of doing this, I am just experimenting with recursion using loop and recur. However the code doesn't seem to work it never returns an answer. (defn fib-even-sum [upto] (loop [previous 1 nxt 1 sum 0] (if (or (<= upto 1) (>= nxt upto)) sum) (if (= (mod nxt 2) 0) (recur nxt (+ previous nxt) (+ sum nxt)) (recur nxt (+ previous nxt) sum)))) I was not sure if I could do recur twice in the same loop or not. I'm not sure if this is causing the problem?

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• Given two lines on a plane, how to find integer points closest to their interseciton?

  - by Lukasz Lew

  I can't solve it: You are given 8 integers: A, B, C representing a line on a plane with equation A*x + B*y = C a, b, c representing another line x, y representing a point on a plane The two lines are not parallel therefore divide plane into 4 pieces. Point (x, y) lies inside of one these pieces. Problem: Write a fast algorithm that will find a point with integer coordinates in the same piece as (x,y) that is closest to the cross point of the two given lines. Note: This is not a homework, this is old Euler-type task that I have absolutely no idea how to approach.

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• Is it hard problem?

  - by Lukasz Lew

  I can't solve it: You are given 8 integers: A, B, C representing a line on a plane with equation A*x + B*y = C a, b, c representing another line x, y representing a point on a plane The two lines are not parallel therefore divide plane into 4 pieces. Point (x, y) lies inside of one these pieces. Problem: Write a fast algorithm that will find a point with integer coordinates in the same piece as (x,y) that is closest to the cross point of the two given lines. Note: This is not a homework, this is old Euler-type task that I have absolutely no idea how to approach.

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• How can I maximally partition a set?

  - by Gregory Higley

  I'm trying to solve one of the Project Euler problems. As a consequence, I need an algorithm that will help me find all possible partitions of a set, in any order. For instance, given the set 2 3 3 5: 2 | 3 3 5 2 | 3 | 3 5 2 | 3 3 | 5 2 | 3 | 3 | 5 2 5 | 3 3 and so on. Pretty much every possible combination of the members of the set. I've searched the net of course, but haven't found much that's directly useful to me, since I speak programmer-ese not advanced-math-ese. Can anyone help me out with this? I can read pretty much any programming language, from BASIC to Haskell, so post in whatever language you wish.

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• Have I checked every consecutive subset of this list?

  - by Nathan

  I'm trying to solve problem 50 on Project Euler. Don't give me the answer or solve it for me, just try to answer this specific question. The goal is to find the longest sum of consecutive primes that adds to a prime below one million. I use wrote a sieve to find all the primes below n, and I have confirmed that it is correct. Next, I am going to check the sum of each subset of consecutive primes using the following method: I have a empty list sums. For each prime number, I add it to each element in sums and check the new sum, then I append the prime to sums. Here it is in python primes = allPrimesBelow(1000000) sums = [] for p in primes: for i in range(len(sums)): sums[i] += p check(sums[i]) sums.append(p) I want to know if I have called check() for every sum of two or more consecutive primes below one million The problem says that there is a prime, 953, that can be written as the sum of 21 consecutive primes, but I am not finding it.

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• Given two lines on a plane, how to find integer points closest to their intersection?

  - by Lukasz Lew

  I can't solve it: You are given 8 integers: A, B, C representing a line on a plane with equation A*x + B*y = C a, b, c representing another line x, y representing a point on a plane The two lines are not parallel therefore divide plane into 4 pieces. Point (x, y) lies inside of one these pieces. Problem: Write a fast algorithm that will find a point with integer coordinates in the same piece as (x,y) that is closest to the cross point of the two given lines. Note: This is not a homework, this is old Euler-type task that I have absolutely no idea how to approach. Update: You can assume that the 8 numbers on input are 32-bit signed integers. But you cannot assume that the solution will be 32 bit.

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• Fastest algorithm to check if a number is pandigital?

  - by medopal

  Pandigital number is a number that contains the digits 1..number length. For example 123, 4312 and 967412385. I have solved many Project Euler problems, but the Pandigital problems always exceed the one minute rule. This is my pandigital function: private boolean isPandigital(int n){ Set<Character> set= new TreeSet<Character>(); String string = n+""; for (char c:string.toCharArray()){ if (c=='0') return false; set.add(c); } return set.size()==string.length(); } Create your own function and test it with this method int pans=0; for (int i=123456789;i<=123987654;i++){ if (isPandigital(i)){ pans++; } } Using this loop, you should get 720 pandigital numbers. My average time was 500 millisecond. I'm using Java, but the question is open to any language.

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• Multiplying numbers on horizontal, vertial, and diagonal lines

  - by untwisted

  I'm currently working on a project Euler problem (www.projecteuler.net) for fun but have hit a stumbling block. One of the problem provides a 20x20 grid of numbers and asks for the greatest product of 4 numbers on a straight line. This line can be either horizontal, vertical, or diagonal. Using a procedural language I'd have no problem solving this, but part of my motivation for doing these problems in the first place is to gain more experience and learn more Haskell. As of right now I'm reading in the grid and converting it to a list of list of ints, eg -- [[Int]]. This makes the horizontal multiplication trivial, and by transposing this grid the vertical also becomes trivial. The diagonal is what is giving me trouble. I've thought of a few ways where I could use explicit array slicing or indexing, to get a solution, but it seems overly complicated and hackey. I believe there is probably an elegant, functional solution here, and I'd love to hear what others can come up with.

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• Python recursive function error: "maximum recursion depth exceeded"

  - by user283169

  I solved Problem 10 of Project Euler with the following code, which works through brute force: def isPrime(n): for x in range(2, int(n**0.5)+1): if n % x == 0: return False return True def primeList(n): primes = [] for i in range(2,n): if isPrime(i): primes.append(i) return primes def sumPrimes(primelist): prime_sum = sum(primelist) return prime_sum print (sumPrimes(primeList(2000000))) The three functions work as follows: isPrime checks whether a number is a prime; primeList returns a list containing a set of prime numbers for a certain range with limit 'n', and; sumPrimes sums up the values of all numbers in a list. (This last function isn't needed, but I liked the clarity of it, especially for a beginner like me.) I then wrote a new function, primeListRec, which does exactly the same thing as primeList, to help me better understand recursion: def primeListRec(i, n): primes = [] #print i if (i != n): primes.extend(primeListRec(i+1,n)) if (isPrime(i)): primes.append(i) return primes return primes The above recursive function worked, but only for very small values, like '500'. The function caused my program to crash when I put in '1000'. And when I put in a value like '2000', Python gave me this: RuntimeError: maximum recursion depth exceeded. What did I do wrong with my recursive function? Or is there some specific way to avoid a recursion limit?

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• Is any solution the correct solution?

  - by Eli

  I always think to myself after solving a programming challenge that I have been tied up with for some time, "It works, thats good enough". I don't think this is really the correct mindset, in my opinion and I think I should always be trying to code with the greatest performance. Anyway, with this said, I just tried a ProjectEuler question. Specifically question #2. How could I have improved this solution. I feel like its really verbose. Like I'm passing the previous number in recursion. <?php /* Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ... Find the sum of all the even-valued terms in the sequence which do not exceed four million. */ function fibonacci ( $number, $previous = 1 ) { global $answer; $fibonacci = $number + $previous; if($fibonacci > 4000000) return; if($fibonacci % 2 == 0) { $answer = is_numeric($answer) ? $answer + $fibonacci : $fibonacci; } return fibonacci($fibonacci, $number); } fibonacci(1); echo $answer; ?> Note this isn't homework. I left school hundreds of years ago. I am just feeling bored and going through the Project Euler questions

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