Strange Frobenius norm of a certain matrix

Yes, the code for the Frobenius norm is missing a square root.
I'll fix this; till then use

mat_norm(m, p) := block([listarith : true, d],
  require_matrix(m,"first","mat_norm"),
  if blockmatrixp(m) then m : mat_fullunblocker(m),
  if p = 1 then mat_norm(transpose(m), 'inf)
  else if p = 'inf then (
    d : 0,
    for ri in m do (
      d : max(d, tree_reduce("+", map('cabs, ri)))),
    d)
  else if p = 'frobenius then sqrt(tree_reduce("+", lreduce('append,
  args(cabs(m)^2))))
  else error("Not able to compute the ",p," norm"));

Thanks for the report.

BW

-----maxima-bounces at math.utexas.edu wrote: -----

>To: maxima at math.utexas.edu
>From: "Paul Smith" <phhs80 at gmail.com>
>Sent by: maxima-bounces at math.utexas.edu
>Date: 09/23/2007 03:54PM
>Subject: Strange Frobenius norm of a certain matrix
>
>Dear All,
>
>Consider the following code:
>
>(%i1) A:matrix([1,1],[1,1]);
>                                   [ 1  1 ]
>(%o1)                              [      ]
>                                   [ 1  1 ]
>(%i2) mat_norm(A,frobenius);
>(%o2)                                  4
>(%i3)
>
>Should not the Frobenius norm of this matrix be equal to 2?
>
>Thanks in advance,
>
>Paul
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