I think I have found a subtle bug in my Maple 9.

If I execute the following code:

###
 B:=[ 3.5, 0.0001, 73.45]; A:=[[seq(1/op(j,B), j=1..3)]];
 writedata("a.txt",A);
###

the output file a.txt contains the line
0.2857142857    1       0.01361470388
(beware: maple has written "1" instead than "10000"!)

Questions:
1) is this bug already known? Is there a patch?
2) does it affect newer versions of Maple?

I would like to perform some operations on all the entries of an array (or an all entries in some given rows/columns).
Can this be achieved without writing an ad hoc loop?
(for instance this task is extremely easy in octave/matlab)
Should I use some specific package?

have a list of lists, and I would like to write each of these lists on a separate file, *on a single line*.

For instance consider the following trivial example:

P := [[-.3819660120, .6180339880, -10000, -2], [.6180339880, 1.618033988, -10000, -1], [1.618033988, 10000, -10000, -.5], [2.618033988, 10000, -.5, -0.1e-3], [2.618033988, 10000, 0.1e-3, .5]]

I would like to create
 + a file named  P1.dat containing the line
     ...

I have some data which have a binary tree structure.

Is there a simple way to plot (at least partially) my binary tree?

In Maple boolean evaluation returns the values 'true' or 'false'.

Is there any canonical way of getting evalb to produce values in {0,1}? This is of some use when testing conjectures on  hudge lists of items...

Of course: you can always define a script like

###########################
evalbb:=proc(PP)
if evalb(PP)='true' then eps:=1:
else eps:=0:
fi:
eps;
end:
###########################

but I think there should be...