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Sum of a series: Difference between revisions
→{{header|Elm}}: 3 different versions, 2 with lists, 1 with recursion
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imported>Polarit (→{{header|Elm}}: 3 different versions, 2 with lists, 1 with recursion) |
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Line 1,004:
module Main exposing (main)
import Html exposing (h1, div, p, text)
import Html.Attributes exposing (style)
aList : List Int
aList = List.range 1 1000
-- version a with a list
<| List.map (\x -> 1.0 / x / x )▼
k2xSum : Float
<| List.map (\n -> toFloat n)▼
k2xSum
▲ <| List.map (\x -> 1.0 / x / x )
▲ <| List.map (\n -> toFloat n) aList
main = ▼
text (" Sum = " ++ String.fromFloat k2xSum)▼
-- version b with a list
fx : Int -> Float
(\n -> toFloat n |> \m -> 1.0 / m / m)
f2kSum : Float
f2kSum = List.sum
<| List.map fx aList
-- version with recursion, without a list
untilMax : Int -> Int -> Float -> Float
untilMax k kmax accum =
if k > kmax
then accum
else
x = toFloat k
dx = 1.0 / x / x
in untilMax (k + 1) kmax (accum + dx)
recSum : Float
recSum = untilMax 1 1000 0.0
main = div [style "margin" "5%", style "color" "blue"] [
h1 [] [text "Sum of series Σ 1/k²"]
▲ , text (" Version a with a list: Sum = " ++ String.fromFloat k2xSum)
, p [] [text (" Version b with a list: Sum = " ++ String.fromFloat f2kSum)]
, p [] [text (" Recursion version c: Sum = " ++ String.fromFloat recSum)]
]
</syntaxhighlight>
{{Out}}
<pre>
Sum of series Σ 1/k²
Sum = 1.6439345666815615▼
Version a with a list: Sum = 1.6439345666815615
</pre>▼
Version b with a list: Sum = 1.6439345666815615
▲</pre>
=={{header|Emacs Lisp}}==
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