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Naive Matrix functions
f#

Hi,

could you please correct / comment my "naive" implantations of some functions?

Thank you

Oldrich

Why there is no unzip for matrices?

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let unzip (el:Matrix<'a*'b>) =

____let first = Matrix.Generic.create el.NumRows el.NumCols (fst el.[0,0])

____let second = Matrix.Generic.create el.NumRows el.NumCols (snd el.[0,0])

____for z = 0 to (el.NumRows-1) do

________for y = 0 to (el.NumCols-1) do

____________first.[z,y] v- fst el.[z,y]

____________second.[z,y] v- snd el.[z,y]

____first,second

The following code is slowlier than recreating a matrix, but for larger matrices it will be necessary, I guess

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let modifyi fn (el:Matrix<_>) =

____for z = 0 to (el.NumRows-1) do

________for y = 0 to (el.NumCols-1) do

____________let res = fn z y el.[z,y]

____________if res <> el.[z,y] then el.[z,y] v- res

Is there any reason why Matrix.Generic.mapi forces to output the same type as input ('T->'T)?

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let mapi f (el:Matrix<_>) =

____Matrix.Generic.init el.NumRows el.NumCols (fun z y -> f z y el.[z,y])

PS: Why all multiple spaces are removed in this forum?

PPS: v- is an assignment. Why we are not allowed to type left bracket (smaller than sign)?

PPS: Somebody should definitely do something with this forum engine...

.

Somewhat unrelated, but the forum engine works fine for me:

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let unzip (el:Matrix) =


  let first = Matrix.Generic.create el.NumRows el.NumCols (fst el.[0,0])


  let second = Matrix.Generic.create el.NumRows el.NumCols (snd el.[0,0])


  for z = 0 to (el.NumRows-1) do


    for y = 0 to (el.NumCols-1) do


      first.[z,y] <- fst el.[z,y]


      second.[z,y] <- snd el.[z,y]


  first,second
By on 11/16/2009 8:20 AM ()

Yeah,

but for me it works only in IE8 with a compatibility view...

By on 11/26/2009 1:22 AM ()

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