## 35 Reputation

13 years, 18 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.

## Truncated floating point (bug?)...

Maple 9

I have run into some queer behaviour of my Maple 9 software. I gave the following commands:

##############################################################
with(numtheory):
xx := invcfrac([[0],[5,1,5,1,4,1]]);
...

## Looking for minimum points in a list...

Maple

I have a set which is represented as a list L (in particular in L there are no repeated values!).

I would like to determine for which index j the element op(j,L) realizes the minimum of L. Is there a built-in function to accomplish this task?

More generally, call OL the list L rearranged in increasing order;  is there a way to determine the permutation which transforms the list L in the list OL?

## Plotting options...

Maple 9

A very useful feature of the plotting program gnuplot is that you can generate an output which is a file instead of a graph. For instance the following short script

################
f(x)=sin(x)+cos(pi*x)
set samples 5000
set table "outfile.dat"
plot [0:10][] f(x)
################

produces a  file containing a sampling of the function f(x) on the interval [0,10] based on a grid...

## writefile syntax...

Maple 9

I have some numerical data, which are very accurate (500 digits) and want to copy them on a text file.

For pratical reason I would like the procedure writefile to write just 20 digits figures: which is the right syntax to use?

## Concatenating strings and floats...

Maple 9

Here is a simple example from the Maple Help (nersion 9.03):
###
i := 5; cat( "The value of i is ", i, "." );
###
which yields
"The value of i is 5."

I would like to use the same syntax to generate a string to be printed at the beginning of a data file (so that I can remember what are the figures in the files); for instance I want to specify that this set has been generated choosing the value of a parameter alpha to be 0.618. So I write

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