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Numeric error propagation: Difference between revisions
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→{{header|REXX}}: added the REXX language.
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m (→{{header|REXX}}: added the REXX language.) |
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{{output}}
<pre>111.803 ± 2.487</pre>
=={{header|REXX}}==
{{trans|Fortran}}
<lang rexx>/*REXX program calculates the distance between two points (2D) with error propagation. */
parse arg a b . /*obtain arguments from the CL*/
if a=='' | a=="," then a= '100±1.1, 50±1.2' /*Not given? Then use default.*/
if b=='' | b=="," then b= '200±2.2, 100±2.3' /* " " " " " */
parse var a ax ',' ay; parse var b bx ',' by /*obtain X,Y from A & B point.*/
parse var ax ax '±' axe; parse var bx bx '±' bxE /* " err " Ax and Bx.*/
parse var ay ay '±' aye; parse var by by '±' byE /* " " " Ay " By.*/
if axE=='' then axE=0; if bxE=='' then bxE=0; /*No error? Then use default.*/
if ayE=='' then ayE=0; if byE=='' then byE=0; /* " " " " " */
say ' A point (x,y)= ' ax "±" axE', ' ay "±" ayE /*display A point (with err)*/
say ' B point (x.y)= ' bx "±" bxE', ' by "±" byE /* " B " " " */
dx=ax-bx; dxE=sqrt(axE**2 + bxE**2); xe=#(dx, 2, dxE) /*compute X distances (& err)*/
dy=ay-by; dyE=sqrt(ayE**2 + byE**2); ye=#(dy, 2, dyE) /* " Y " " " */
D=sqrt(dx**2 + dy**2) /*compute the 2D distance. */
say /*blank line for the eyeballs.*/
say 'distance=' D "±" #(D**2, .5, sqrt(xE**2 + yE**2)) /*display " " " */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
#: procedure; arg x,p,e; a=abs(x); if p=.5 then z=1/sqrt(a); else z=a**(p-1); return p*e*z
/*──────────────────────────────────────────────────────────────────────────────────────*/
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
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*/
numeric digits d; return g/1</lang>
'''output''' when using the default inputs:
<pre>
A point (x,y)= 100 ± 1.1, 50 ± 1.2
B point (x.y)= 200 ± 2.2, 100 ± 2.3
distance= 111.803399 ± 2.48716707
</pre>
=={{header|Ruby}}==
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