## 35 Reputation

12 years, 235 days
Universita' di Pisa
Dr.

I am a researcher working in Pisa.

In a nutshell, I am interested in dyanamical systems, ergodic theory and number theory (expecially issues connected with continued fractions).

I am using Maple (mostly in a naive way :) to investigate some combinatorial issues arising from my research.

## Bug in procedure writefile of Maple9...

Maple 9

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?

## Operations on entries of an array...

Maple 9

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?

## writedata (on a single line)...

Maple

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
...

## Plotting binary trees...

Maple 9

I have some data which have a binary tree structure.

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

## Boolean evaluation...

Maple 9

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...

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