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 Author Comment/Response Forum Moderator email me 11/02/02 4:04pm This is an evaluation issue. If you drop the semi-colon in your definition, you will see the following: In[17]:= F[n_]=Table[ If[i\[NotEqual]n&&i\[Equal]j,1,If[i>j||j\[Equal]n,(-1)^(i+j-1),0]],{i,1, 3},{j,1,3}] Out[17]= {{If[1 != n, 1, If[i > j || j == n, (-1)^(i + j - 1), 0]], If[2 == n, (-1)^(i + j - 1), 0], If[3 == n, (-1)^(i + j - 1), 0]}, {1, If[2 != n, 1, If[i > j || j == n, (-1)^(i + j - 1), 0]], If[3 == n, (-1)^(i + j - 1), 0]}, {-1, 1, If[3 != n, 1, If[i > j || j == n, (-1)^(i + j - 1), 0]]}} My guess is that since n is not known, the evaluation of the expressions that contain n is not carried out. I'd look further into it, but this is easy to resolve using SetDelayed (written := ) In[20]:= Clear[F] In[21]:= F[n_]:=Table[ If[Evaluate[i\[NotEqual]n&&i\[Equal]j],1, If[Evaluate[i>j||j\[Equal]n],(-1)^(i+j-1),0]],{i,1,3},{j,1,3}] In[22]:= F[3] Out[22]= {{1,0,-1},{1,1,1},{-1,1,-1}} There are various articles on evaluation, Set and SetDelayed in the Help Browser URL: ,

 Subject (listing for 'unexpected output from matrix creation') Author Date Posted unexpected output from matrix creation Nathan C. Lee 10/31/02 08:54am Re: unexpected output from matrix creation Forum Modera... 11/02/02 4:04pm
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