math.intervals: tighter interval arithmetic for intervals with infinities

Slava Pestov 2009-08-19 02:32:18 -05:00
parent fbb9209032
commit 4b53916a12
2 changed files with 32 additions and 21 deletions

View File

@ -348,6 +348,10 @@ comparison-ops [
[ t ] [ -10 10 [a,b] interval-abs 0 10 [a,b] = ] unit-test
[ t ] [ full-interval interval-abs [0,inf] = ] unit-test
[ t ] [ [0,inf] interval-sq [0,inf] = ] unit-test
! Test that commutative interval ops really are
: random-interval-or-empty ( -- obj )
10 random 0 = [ empty-interval ] [ random-interval ] if ;

View File

@ -94,21 +94,25 @@ MEMO: array-capacity-interval ( -- interval )
: interval>points ( int -- from to )
[ from>> ] [ to>> ] bi ;
: points>interval ( seq -- interval )
dup [ first fp-nan? ] any?
[ drop [-inf,inf] ] [
dup first
[ [ endpoint-min ] reduce ]
[ [ endpoint-max ] reduce ]
2bi <interval>
] if ;
: points>interval ( seq -- interval nan? )
[ first fp-nan? not ] partition
[
[ [ ] [ endpoint-min ] map-reduce ]
[ [ ] [ endpoint-max ] map-reduce ] bi
<interval>
]
[ empty? not ]
bi* ;
: nan-ok ( interval nan? -- interval ) drop ; inline
: nan-not-ok ( interval nan? -- interval ) [ drop full-interval ] when ; inline
: (interval-op) ( p1 p2 quot -- p3 )
[ [ first ] [ first ] [ call ] tri* ]
[ drop [ second ] both? ]
3bi 2array ; inline
: interval-op ( i1 i2 quot -- i3 )
: interval-op ( i1 i2 quot -- i3 nan? )
{
[ [ from>> ] [ from>> ] [ ] tri* (interval-op) ]
[ [ to>> ] [ from>> ] [ ] tri* (interval-op) ]
@ -126,10 +130,10 @@ MEMO: array-capacity-interval ( -- interval )
} cond ; inline
: interval+ ( i1 i2 -- i3 )
[ [ + ] interval-op ] do-empty-interval ;
[ [ + ] interval-op nan-ok ] do-empty-interval ;
: interval- ( i1 i2 -- i3 )
[ [ - ] interval-op ] do-empty-interval ;
[ [ - ] interval-op nan-ok ] do-empty-interval ;
: interval-intersect ( i1 i2 -- i3 )
{
@ -154,7 +158,7 @@ MEMO: array-capacity-interval ( -- interval )
{ [ dup empty-interval eq? ] [ drop ] }
{ [ over full-interval eq? ] [ drop ] }
{ [ dup full-interval eq? ] [ nip ] }
[ [ interval>points 2array ] bi@ append points>interval ]
[ [ interval>points 2array ] bi@ append points>interval nan-not-ok ]
} cond ;
: interval-subset? ( i1 i2 -- ? )
@ -173,7 +177,7 @@ MEMO: array-capacity-interval ( -- interval )
0 swap interval-contains? ;
: interval* ( i1 i2 -- i3 )
[ [ [ * ] interval-op ] do-empty-interval ]
[ [ [ * ] interval-op nan-ok ] do-empty-interval ]
[ [ interval-zero? ] either? ]
2bi [ 0 [a,a] interval-union ] when ;
@ -220,7 +224,7 @@ MEMO: array-capacity-interval ( -- interval )
[
[
[ interval-closure ] bi@
[ shift ] interval-op
[ shift ] interval-op nan-not-ok
] interval-integer-op
] do-empty-interval ;
@ -235,11 +239,11 @@ MEMO: array-capacity-interval ( -- interval )
: interval-max ( i1 i2 -- i3 )
#! Inaccurate; could be tighter
[ [ interval-closure ] bi@ [ max ] interval-op ] do-empty-interval ;
[ [ interval-closure ] bi@ [ max ] interval-op nan-not-ok ] do-empty-interval ;
: interval-min ( i1 i2 -- i3 )
#! Inaccurate; could be tighter
[ [ interval-closure ] bi@ [ min ] interval-op ] do-empty-interval ;
[ [ interval-closure ] bi@ [ min ] interval-op nan-not-ok ] do-empty-interval ;
: interval-interior ( i1 -- i2 )
dup special-interval? [
@ -254,7 +258,7 @@ MEMO: array-capacity-interval ( -- interval )
} cond ; inline
: interval/ ( i1 i2 -- i3 )
[ [ [ / ] interval-op ] interval-division-op ] do-empty-interval ;
[ [ [ / ] interval-op nan-not-ok ] interval-division-op ] do-empty-interval ;
: interval/-safe ( i1 i2 -- i3 )
#! Just a hack to make the compiler work if bootstrap.math
@ -266,13 +270,13 @@ MEMO: array-capacity-interval ( -- interval )
[
[
[ interval-closure ] bi@
[ /i ] interval-op
[ /i ] interval-op nan-not-ok
] interval-integer-op
] interval-division-op
] do-empty-interval ;
: interval/f ( i1 i2 -- i3 )
[ [ [ /f ] interval-op ] interval-division-op ] do-empty-interval ;
[ [ [ /f ] interval-op nan-not-ok ] interval-division-op ] do-empty-interval ;
: (interval-abs) ( i1 -- i2 )
interval>points [ first2 [ abs ] dip 2array ] bi@ 2array ;
@ -281,10 +285,13 @@ MEMO: array-capacity-interval ( -- interval )
{
{ [ dup empty-interval eq? ] [ ] }
{ [ dup full-interval eq? ] [ drop [0,inf] ] }
{ [ 0 over interval-contains? ] [ (interval-abs) { 0 t } suffix points>interval ] }
[ (interval-abs) points>interval ]
{ [ 0 over interval-contains? ] [ (interval-abs) { 0 t } suffix points>interval nan-not-ok ] }
[ (interval-abs) points>interval nan-not-ok ]
} cond ;
: interval-absq ( i1 -- i2 )
interval-abs interval-sq ;
: interval-recip ( i1 -- i2 ) 1 [a,a] swap interval/ ;
: interval-2/ ( i1 -- i2 ) -1 [a,a] interval-shift ;