steve
/
factor
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

math.extras: adding bitwise permutation words.

db4
John Benediktsson 2013-04-10 14:29:23 -07:00
parent 86ad529ed7
commit 336e2bfd58
3 changed files with 29 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
extra/math/extras/extras-docs.factor
View File

@ -86,3 +86,11 @@ HELP: round-to-decimal
{ $example "USING: math.extras prettyprint ;" "1.23456 2 round-to-decimal ." "1.23" } { $example "USING: math.extras prettyprint ;" "1.23456 2 round-to-decimal ." "1.23" }
{ $example "USING: math.extras prettyprint ;" "12345.6789 -3 round-to-decimal ." "12000.0" } { $example "USING: math.extras prettyprint ;" "12345.6789 -3 round-to-decimal ." "12000.0" }
} ; } ;
HELP: next-permutation-bits
{ $values { "v" integer } { "w" integer } }
{ $description "Generates the next bitwise permutation with the same number of set bits, given a previous lexicographical value." } ;
HELP: permutation-bits
{ $values { "bit-count" integer } { "bits" integer } { "seq" sequence } }
{ $description "Generates all permutations of numbers with a given bit-count and number of bits." } ;

10
extra/math/extras/extras-tests.factor
View File

@ -129,3 +129,13 @@ IN: math.extras.test
{ 5 } [ 3 5 round-to-step ] unit-test { 5 } [ 3 5 round-to-step ] unit-test
{ 10 } [ 12 5 round-to-step ] unit-test { 10 } [ 12 5 round-to-step ] unit-test
{ 15 } [ 13 5 round-to-step ] unit-test { 15 } [ 13 5 round-to-step ] unit-test
{ 0b101 } [ 0b11 next-permutation-bits ] unit-test
{ 0b110 } [ 0b101 next-permutation-bits ] unit-test
{
{
0b00111 0b01011 0b01101 0b01110 0b10011
0b10101 0b10110 0b11001 0b11010 0b11100
}
} [ 3 5 permutation-bits ] unit-test

13
extra/math/extras/extras.factor
View File

@ -3,8 +3,8 @@
USING: accessors arrays assocs assocs.extras byte-arrays USING: accessors arrays assocs assocs.extras byte-arrays
combinators combinators.short-circuit compression.zlib fry combinators combinators.short-circuit compression.zlib fry
grouping kernel locals math math.combinatorics math.constants grouping kernel locals math math.bitwise math.combinatorics
math.functions math.order math.primes math.ranges math.constants math.functions math.order math.primes math.ranges
math.ranges.private math.statistics math.vectors memoize random math.ranges.private math.statistics math.vectors memoize random
sequences sequences.extras sets sorting ; sequences sequences.extras sets sorting ;
@ -258,3 +258,12 @@ M: float round-to-even
: round-to-step ( x step -- y ) : round-to-step ( x step -- y )
[ [ / round ] [ * ] bi ] unless-zero ; [ [ / round ] [ * ] bi ] unless-zero ;
: next-permutation-bits ( v -- w )
[ dup 1 - bitor 1 + dup ] keep
[ dup neg bitand ] bi@ / -1 shift 1 - bitor ;
: permutation-bits ( bit-count bits -- seq )
[ on-bits dup '[ dup _ >= ] ]
[ on-bits '[ [ next-permutation-bits _ bitand ] keep ] ]
bi* produce nip ;