Pell's equation: Difference between revisions
Content added Content deleted
(→{{header|Python}}: It's far more Pythonic to use multiple assignment than a helper method which uses arrays for pass-by-reference) |
m (→{{header|REXX}}: added commas to the huge numbers, simplified the SAY expressions for the output of X and Y.) |
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=={{header|REXX}}== |
=={{header|REXX}}== |
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A little extra code was added to align and commatize the gihugeic numbers for readability. |
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<lang rexx>/*REXX program to solve Pell's equation for the smallest solution of positive integers. */ |
<lang rexx>/*REXX program to solve Pell's equation for the smallest solution of positive integers. */ |
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numeric digits 2200 /*ensure enough decimal digs for answer*/ |
numeric digits 2200 /*ensure enough decimal digs for answer*/ |
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parse arg $ /*obtain optional arguments from the CL*/ |
parse arg $ /*obtain optional arguments from the CL*/ |
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if $=='' | $=="," then $= 61 109 181 277 /*Not specified? Then use the defaults*/ |
if $=='' | $=="," then $= 61 109 181 277 /*Not specified? Then use the defaults*/ |
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d= |
d= 28 /*used for aligning the output numbers.*/ |
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do j=1 for words($); #= word($, j) |
do j=1 for words($); #= word($, j) /*process all the numbers in the list. */ |
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parse value pells(#) with x y |
parse value pells(#) with x y /*extract the two values of X and Y.*/ |
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cx= comma(x); Lcx= length(cx); cy= comma(y); Lcy= length(cy); L#= length(#) |
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say 'x^2 -'right(#, max(4, L#)) "* y^2 == 1" , |
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| ⚫ | |||
' when x='right(cx, max(d, Lcx)) " and y="right(cy, max(d, Lcy)) |
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end /*j*/ |
end /*j*/ |
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exit /*stick a fork in it, we're all done. */ |
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| ⚫ | |||
/*──────────────────────────────────────────────────────────────────────────────────────*/ |
/*──────────────────────────────────────────────────────────────────────────────────────*/ |
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comma: parse arg ?; do jc=length(?)-3 to 1 by -3; ?= insert(',', ?, jc); end; return ? |
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floor: procedure; parse arg x; _= x % 1; return _ - (x < 0) * (x \= _) |
floor: procedure; parse arg x; _= x % 1; return _ - (x < 0) * (x \= _) |
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/*──────────────────────────────────────────────────────────────────────────────────────*/ |
/*──────────────────────────────────────────────────────────────────────────────────────*/ |
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{{out|output|text= when using the default inputs:}} |
{{out|output|text= when using the default inputs:}} |
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<pre> |
<pre> |
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x^2 - 61 * y^2 == 1 when x= |
x^2 - 61 * y^2 == 1 when x= 1,766,319,049 and y= 226,153,980 |
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x^2 - 109 * y^2 == 1 when x= |
x^2 - 109 * y^2 == 1 when x= 158,070,671,986,249 and y= 15,140,424,455,100 |
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x^2 - 181 * y^2 == 1 when x= |
x^2 - 181 * y^2 == 1 when x= 2,469,645,423,824,185,801 and y= 183,567,298,683,461,940 |
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x^2 - 277 * y^2 == 1 when x= |
x^2 - 277 * y^2 == 1 when x= 159,150,073,798,980,475,849 and y= 9,562,401,173,878,027,020 |
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</pre> |
</pre> |
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