algorithm - How to get all 24 rotations of a 3-dimensional array? -

-

i have 3-dimensional array. think of brick. there 24 possible rotations of brick (that keep edges parallel coordinate axes). how generate corresponding 3-dimensional arrays?

a die (half pair of dice) handy observing 24 different orientations, , can suggest operation sequences generate them. see of 6 faces can uppermost, , sides below can rotated 4 different cardinal directions. let denote 2 operations: “turn” , “roll”, turn rotates die z axis 1 cardinal next, , roll rotates die 90° away you, away-face becomes bottom face , near face top. these operations can expressed using rotation matrices mentioned in answer of felipe lopes, or can expressed simple functions when given (x,y,z) return (-y,x,z) or (x,z,-y), respectively.

anyhow, if place die 1 on near face, 2 @ right, , 3 on top, find following sequence of steps generates twelve different orientations 1, 2, or 3 spots on top: rtttrtttrttt. sequence rtr exposes 6, 4, 5 1, 2, 3 were, , repeat of sequence rtttrtttrttt generates twelve orientations 4, 5, or 6 spots on top. mentioned sequence embedded in following python code.

def roll(v): return (v[0],v[2],-v[1]) def turn(v): return (-v[1],v[0],v[2]) def sequence (v):     cycle in range(2):         step in range(3):  # yield rttt 3 times             v = roll(v)             yield(v)           #    yield r             in range(3): #    yield ttt                 v = turn(v)                 yield(v)         v = roll(turn(roll(v)))  # rtr  p = sequence(( 1, 1, 1)) q = sequence((-1,-1, 1)) in sorted(zip(p,q)):     print

the rationale printing out sorted list of transformed pairs of points twofold: (i) face orientation can specified locations of 2 of corners; (ii) easy check uniqueness of each pair, eg piping output uniq.

here how sorted output begins:

((-1, -1, -1), (-1, 1, 1)) ((-1, -1, -1), (1, -1, 1)) ((-1, -1, -1), (1, 1, -1)) ((-1, -1, 1), (-1, 1, -1)) ((-1, -1, 1), (1, -1, -1)) ((-1, -1, 1), (1, 1, 1)) ((-1, 1, -1), (-1, -1, 1)) ((-1, 1, -1), (1, -1, -1)) ((-1, 1, -1), (1, 1, 1))

Comments

Post a Comment

Popular posts from this blog

java - Jmockit String final length method mocking Issue -

-
using jmockit 1.2 jar, trying mock string's length method getting unexpected invocation exception: failed: test java.lang.illegalstateexception: missing invocation mocked type @ point; please make sure such invocations appear after declaration of suitable mock field or parameter @ stringdemo.testa$1.<init>(testa.java:17) @ stringdemo.testa.test(testa.java:13) i using testng: @test public void test() throws exception { new expectations() { @mocked("length") string astring; { astring.length(); result = 2; } }; system.out.println(a.showa("test")); } } actual class a: public class { public static int showa(string str){ int a= str.length(); return a; } } this wrong way of recording expected results. shouldn't mock , record string's length() method, record showa() instead. here solution @suppresswarnings("unused...
Read more

What is the difference between data design and data model(ERD) -

-
i have google question , find answer in day. know, data design many many table have list column,and mark pk , fk. why er-diagram have find this? data design process of designing database. main output of data design detailed logical data model of database. some people data design includes of needed logical , physical design choices , physical storage parameters needed generate design in data definition language. technically, database analysis, database analysts (dbas) trained do. while person can both data design , database analysis, these 2 different tasks. data design models data. database analysis takes model , applies 1 or more database engines (relational, hierarchical, nosql). a logical data model 1 of main outputs of data design. data model represented entity relationship diagram, or er diagram.
Read more

ios - Can NSManagedObject conform to NSCoding -

-
i need transfer single object across device. right converting nsmanagedobject dictionary , archiving , sending nsdata. upon receiving unarchiving it. transfer nsmanagedobject archiving , unarchiving instead of creating intermediate data object. @interface test : nsmanagedobject<nscoding> @property (nonatomic, retain) nsstring * title; @end @implementation test @dynamic title; - (id)initwithcoder:(nscoder *)coder { self = [super init]; if (self) { self.title = [coder decodeobjectforkey:@"title"]; //<crash } return self; } - (void)encodewithcoder:(nscoder *)coder { [coder encodeobject:self.title forkey:@"title"]; } @end nsdata *archivedobjects = [nskeyedarchiver archiveddatawithrootobject:testobj]; nsdata *objectsdata = archivedobjects; if ([objectsdata length] > 0) { nsarray *objects = [nskeyedunarchiver unarchiveobjectwithdata:objectsdata]; } the problem above code is. crashes @ self.title in initwithcoder sa...
Read more