Summarize primes: Difference between revisions
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@.1=2; @.2=3; @.3=5; @.4=7; @.5=11 /*define some low primes. */ |
@.1=2; @.2=3; @.3=5; @.4=7; @.5=11 /*define some low primes. */ |
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!.2=1; !.3=1; !.5=1; !.7=1; !.11=1 /* " " " " flags. */ |
!.2=1; !.3=1; !.5=1; !.7=1; !.11=1 /* " " " " flags. */ |
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#=5; |
#=5; sq.#= @.# **2 /*number of primes so far; prime². */ |
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/* [↓] generate more primes ≤ high.*/ |
/* [↓] generate more primes ≤ high.*/ |
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do j=@.#+2 by 2 until @.#>=hi & @.#>sP /*find odd primes where P≥hi and P>sP.*/ |
do j=@.#+2 by 2 until @.#>=hi & @.#>sP /*find odd primes where P≥hi and P>sP.*/ |
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parse var j '' -1 _; if |
parse var j '' -1 _; if _==5 then iterate /*J ÷ by 5? (right digit)*/ |
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if j//3==0 then iterate; if j//7==0 then iterate /*J ÷ by 3?; J ÷ by 7? */ |
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do k=5 while sq.k<=j /* [↓] divide by the known odd primes.*/ |
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do k=5 while s.k<=j /* [↓] divide by the known odd primes.*/ |
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if j // @.k == 0 then iterate j /*Is J ÷ X? Then not prime. ___ */ |
if j // @.k == 0 then iterate j /*Is J ÷ X? Then not prime. ___ */ |
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end /*k*/ /* [↑] only process numbers ≤ √ J */ |
end /*k*/ /* [↑] only process numbers ≤ √ J */ |
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#= #+1; @.#= j; |
#= #+1; @.#= j; sq.#= j*j; !.j= 1 /*bump # Ps; assign next P; P square; P*/ |
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if @.#<hi then sP= sP + @.# /*maybe add this prime to sum─of─primes*/ |
if @.#<hi then sP= sP + @.# /*maybe add this prime to sum─of─primes*/ |
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end /*j*/; return</lang> |
end /*j*/; return</lang> |
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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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