Closest-pair problem: Difference between revisions

Content added Content deleted
m (→‎{{header|REXX}}: added/changed comments and whitespace, used a template for the outputs.)
Line 3,668: Line 3,668:
<lang rexx>/*REXX program solves the closest pair of points problem (in two dimensions). */
<lang rexx>/*REXX program solves the closest pair of points problem (in two dimensions). */
parse arg N low high seed . /*obtain optional arguments from the CL*/
parse arg N low high seed . /*obtain optional arguments from the CL*/
if N=='' | N=="," then N= 100 /*Not specified? Then use the default.*/
if N=='' | N=="," then N= 100 /*Not specified? Then use the default.*/
if low=='' | low=="," then low= 0 /* " " " " " " */
if low=='' | low=="," then low= 0 /* " " " " " " */
if high=='' | high=="," then high=20000 /* " " " " " " */
if high=='' | high=="," then high= 20000 /* " " " " " " */
if datatype(seed,'W') then call random ,,seed /*seed for RANDOM (BIF) repeatability.*/
if datatype(seed, 'W') then call random ,,seed /*seed for RANDOM (BIF) repeatability.*/
w=length(high); w=w + (w//2==0)
w=length(high); w=w + (w//2==0) /*W: for aligning the output columns.*/
/*╔══════════════════════╗*/ do j=1 for N /*generate N random points.*/
/*╔══════════════════════╗*/ do j=1 for N /*generate N random points*/
/*║ generate N points. ║*/ @x.j=random(low,high) /* " a random X. */
/*║ generate N points. ║*/ @x.j=random(low, high) /* " a random X */
/*╚══════════════════════╝*/ @y.j=random(low,high) /* " " " Y. */
/*╚══════════════════════╝*/ @y.j=random(low, high) /* " " " Y */
end /*j*/ /*X and Y make the point*/
end /*j*/ /*X & Y make the point.*/
A=1; B=2 /* [↓] MINDD is actually the unsquared*/
A=1; B=2 /* [↓] MINDD is actually the squared*/
minDD=(@x.A-@x.B)**2 + (@y.A-@y.B)**2 /*distance between the first two points*/
minDD= (@x.A - @x.B)**2 + (@y.A - @y.B)**2 /*distance between the first two points*/
/* [↓] use of XJ & YJ speed things up.*/
/* [↓] use of XJ & YJ speed things up.*/
do j=1 for N-1; xj=@x.j; yj=@y.j /*find minimum distance between a ··· */
do j=1 for N-1; xj=@x.j; yj=@y.j /*find minimum distance between a ··· */
do k=j+1 to N /* ··· point and all the other points.*/
do k=j+1 to N /* ··· point and all the other points.*/
dd=(xj - @x.k)**2 + (yj - @y.k)**2 /*compute squared distance from points.*/
dd=(xj - @x.k)**2 + (yj - @y.k)**2 /*compute squared distance from points.*/
if dd<minDD then if dd\=0 then parse value dd j k with minDD A B
if dd<minDD then if dd\=0 then parse value dd j k with minDD A B
end /*k*/ /* [↑] needn't take SQRT of DD (yet).*/
end /*k*/ /* [↑] needn't take SQRT of DD (yet).*/
end /*j*/ /* [↑] when done, A & B are the ones*/
end /*j*/ /* [↑] when done, A & B are the points*/
$= 'For ' N " points, the minimum distance between the two points: "

_= 'For ' N " points, the minimum distance between the two points: "
say $ center("x", w, '═')" " center('y', w, "═") ' is: ' sqrt(abs(minDD))/1
say _ center("x", w, '═')" " center('y', w, "═") ' is: ' sqrt(abs(minDD))/1
say left('', length($) - 1) "["right(@x.A, w)',' right(@y.A, w)"]"
say left('', length(_)-1) "["right(@x.A, w)',' right(@y.A, w)"]"
say left('', length($) - 1) "["right(@x.B, w)',' right(@y.B, w)"]"
say left('', length(_)-1) "["right(@x.B, w)',' right(@y.B, w)"]"
exit /*stick a fork in it, we're all done. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
sqrt: procedure; parse arg x; if x=0 then return 0; d=digits(); m.=9; numeric form; h=d+6
sqrt: procedure; parse arg x; if x=0 then return 0; d=digits(); m.=9; numeric form; h=d+6
numeric digits; parse value format(x,2,1,,0) 'E0' with g 'E' _ .; g=g *.5'e'_ % 2
numeric digits; parse value format(x,2,1,,0) 'E0' with g 'E' _ .; g=g *.5'e'_ % 2
do j=0 while h>9; m.j=h; h=h%2+1; end /*j*/
do j=0 while h>9; m.j=h; h=h%2+1; end /*j*/
do k=j+5 to 0 by -1; numeric digits m.k; g=(g+x/g)*.5; end /*k*/
do k=j+5 to 0 by -1; numeric digits m.k; g=(g+x/g)*.5; end /*k*/; return g</lang>
⚫
{{out|output|text=&nbsp; when using the default input of: &nbsp; <tt> 100 </tt>}}
return g</lang>
⚫
'''output''' &nbsp; when using the default input of: &nbsp; <tt> 100 </tt>
<pre>
<pre>
For 100 points, the minimum distance between the two points: ══x══ ══y══ is: 219.228192
For 100 points, the minimum distance between the two points: ══x══ ══y══ is: 219.228192
Line 3,704: Line 3,702:
[ 7483, 1700]
[ 7483, 1700]
</pre>
</pre>
'''output''' &nbsp; when using the input of: &nbsp; <tt> 200 </tt>
{{out|output|text=&nbsp; when using the input of: &nbsp; <tt> 200 </tt>}}
<pre>
<pre>
For 200 points, the minimum distance between the two points: ══x══ ══y══ is: 39.408121
For 200 points, the minimum distance between the two points: ══x══ ══y══ is: 39.408121
Line 3,710: Line 3,708:
[17627, 19198]
[17627, 19198]
</pre>
</pre>
'''output''' &nbsp; when using the input of: &nbsp; <tt> 1000 </tt>
{{out|output|text=&nbsp; when using the input of: &nbsp; <tt> 1000 </tt>
<pre>
}}<pre>
For 1000 points, the minimum distance between the two points: ══x══ ══y══ is: 5.09901951
For 1000 points, the minimum distance between the two points: ══x══ ══y══ is: 5.09901951
[ 6264, 19103]
[ 6264, 19103]
Retrieved from "https://rosettacode.org/wiki/Closest-pair_problem"