{ $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" }
} ;
-
-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: all-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." } ;
{ 5 } [ 3 5 round-to-step ] unit-test
{ 10 } [ 12 5 round-to-step ] unit-test
{ 15 } [ 13 5 round-to-step ] unit-test
-
-{ 0b101 } [ 0b011 next-permutation-bits ] unit-test
-{ 0b110 } [ 0b101 next-permutation-bits ] unit-test
-
-{
- {
- 0b00111 0b01011 0b01101 0b01110 0b10011
- 0b10101 0b10110 0b11001 0b11010 0b11100
- }
-} [ 3 5 all-permutation-bits ] unit-test
-
-{ { 14 22 26 28 38 42 44 50 52 56 } } [ 3 5 [ 2 * ] map-permutation-bits ] unit-test
-
-{ V{ 14 22 26 28 } } [ 3 5 [ even? ] filter-permutation-bits ] unit-test
-
-{ 14 } [ 3 5 [ even? ] find-permutation-bits ] unit-test
-{ f } [ 3 5 [ 0 < ] find-permutation-bits ] unit-test
USING: accessors arrays assocs assocs.extras byte-arrays
combinators combinators.short-circuit compression.zlib fry
-grouping kernel locals math math.bitwise math.combinatorics
-math.constants math.functions math.order math.primes math.ranges
+grouping kernel locals math math.combinatorics math.constants
+math.functions math.order math.primes math.ranges
math.ranges.private math.statistics math.vectors memoize random
sequences sequences.extras sets sorting ;
: round-to-step ( x step -- y )
[ [ / round ] [ * ] bi ] unless-zero ;
-
-: next-permutation-bits ( v -- w )
- [ dup 1 - bitor 1 + dup ] keep
- [ dup neg bitand ] bi@ /i 2/ 1 - bitor ;
-
-<PRIVATE
-
-: permutation-bits-quot ( bit-count bits quot -- n pred body )
- [ [ on-bits dup '[ dup _ >= ] ] [ on-bits ] bi* ] dip swap
- '[ _ [ next-permutation-bits _ bitand ] bi ] ; inline
-
-PRIVATE>
-
-: each-permutation-bits ( ... bit-count bits quot: ( ... n -- ... ) -- ... )
- permutation-bits-quot while drop ; inline
-
-: map-permutation-bits ( ... bit-count bits quot: ( ... n -- ... m ) -- ... seq )
- permutation-bits-quot [ swap ] compose produce nip ; inline
-
-: filter-permutation-bits ( ... bit-count bits quot: ( ... n -- ... ? ) -- ... seq )
- selector [ each-permutation-bits ] dip ; inline
-
-: all-permutation-bits ( bit-count bits -- seq )
- [ ] map-permutation-bits ;
-
-: find-permutation-bits ( ... bit-count bits quot: ( ... n -- ... ? ) -- ... elt/f )
- [ f f ] 3dip [ 2nip ] prepose [ keep swap ] curry
- permutation-bits-quot [ [ pick not and ] compose ] dip
- while drop swap and ; inline
-
-: reduce-permutation-bits ( ... bit-count bits identity quot: ( ... prev elt -- ... next ) -- ... result )
- [ -rot ] dip each-permutation-bits ; inline