Module graphic sur caml

Bonjour,
j'essaies de transformer une matrice en image à l'aide du module graphics sur caml light, mais cela ne marche pas :

Pour dessiner la matrice:

Code:

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1 2	let coloriage_matrice M= open_graph "1000x1000"; draw_image (make_image M) ;;

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Le programme pour créer une matrice "damier":

Code:

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let damier M = let (n,p)=dims M in for i=0 to (n-1) do for j= 0 to (p-1) do if (i+j) mod 2= 0 then M.(i).(j)<-white else M.(i).(j)<-black done done;M ;;

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Code:

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#load "graphics.cma" module G = Graphics   let make_img_matrix (n, p) = let m = Array.make_matrix p n G.red in for i = 0 to (n-1) do for j = 0 to (p-1) do m.(j).(i) <- if (i+j) mod 32 = 0 then G.white else G.black done done; (m)   let display_matrix m = G.draw_image (G.make_image m) 0 0   let _ = G.open_graph " 640x480"; let dims = (G.size_x (), G.size_y ()) in let m = make_img_matrix dims in display_matrix m; G.read_key ()

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