Matrix multiplication: Difference between revisions

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 =={{header|Standard ML}}==
-<lang sml>structure Matrix = struct
+<lang sml>structure IMatrix = struct
+fun dot(x,y) = Vector.foldli (fn (i,xi,agg) => agg+xi*Vector.sub(y,i)) 0 x
-local
+fun x*y =
-    open Array2
+    let
-    fun dot(x,y) = Vector.foldli (fn (i,xi,agg) => agg+xi*Vector.sub(y,i)) 0 x
+	open Array2
-in
+    in
-val fromList = fromList
-fun x*y = tabulate ColMajor (nRows x, nCols y, fn (i,j) => dot(row(x,i),column(y,j)))
+	tabulate ColMajor (nRows x, nCols y, fn (i,j) => dot(row(x,i),column(y,j)))
+    end
+end;
 (* for display *)
 fun toList a =
+    let
-    List.tabulate(nRows a, fn i => List.tabulate(nCols a, fn j => sub(a,i,j)))
+	open Array2
-end
+    in
-end;
+	List.tabulate(nRows a,  fn i => List.tabulate(nCols a, fn j => sub(a,i,j)))
+    end;
 (* example *)
+let
-let open Matrix
+    open IMatrix
-    val m1 = fromList [[1,2],[3,4]]
-    val m2 = fromList [[~3,~8,3],[~2,1,4]]
+    val m1 = Array2.fromList [[1,2],[3,4]]
+    val m2 = Array2.fromList [[~3,~8,3],[~2,1,4]]
 in
     toList (m1*m2)
 end;</lang>
 '''Output:'''