Magic squares of doubly even order: Difference between revisions

Content added Content deleted
m (→‎{{header|Haskell}}: (Tweaked the point at which the 'magic series' starts, for more natural indexing)
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=={{header|Haskell}}==
=={{header|Haskell}}==


<lang Haskell>import Data.List (transpose)
<lang Haskell>module DoubleEvenMagic where
import Data.List (transpose)
magicSquare :: Int -> [[Int]]
magicSquare :: Int -> [[Int]]
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-- yields the truth table that we need
-- yields the truth table that we need
| isPowerOf 2 n =
| isPowerOf 2 n =
magicSeries $ floor (logBase 2 (fromIntegral sqr)) + 1
magicSeries $ floor (logBase 2 (fromIntegral sqr))
-- where n is not a power of 2, we can replicate a
-- where n is not a power of 2, we can replicate a
-- minimum truth table, horizontally and vertically
-- minimum truth table, horizontally and vertically
| otherwise = (concat $ concat $ concat $
| otherwise = (concat $ concat $ concat $
scale $ fmap scale $ splitEvery 4 $ magicSeries 5)
scale $ fmap scale $ splitEvery 4 $ magicSeries 4)
where scale = replicate $ quot n 4
where scale = replicate $ quot n 4




-----------------------------------------------------------------------
------------------------------------------------------------------------
magicSeries :: Int -> [Bool]
magicSeries :: Int -> [Bool]
magicSeries n
magicSeries n
| n <= 1 = [True]
| n <= 1 = [True, False]
| otherwise = xs ++ (not <$> xs)
| otherwise = xs ++ (not <$> xs)
where
where
Retrieved from "https://rosettacode.org/wiki/Magic_squares_of_doubly_even_order"