You need to have the GMP library already installed.
cd CoCoALib-0.99 ./configure make
(if you have N cores you may use them typing make -jN
).
This will compile the library and run a series of tests. The code is
quite portable, so just wait faithfully (don't worry about some
warning
s), and after a few minutes you'll get the reassuring
message:
Good news: all tests passed
If not, you probably have some problems with your gmp or g++ installation. If you think it is a genuine problem with CoCoALib send an email to cocoa at dima.unige.it
As we know that no one likes to read documentation, we provide an examples/ directory full of sample code using CoCoALib. To run an example do this:
cd examples make ex-yyyyy <--- without the ".C" ./ex-yyyyy
If you want to experiment with CoCoALib in your personal directory,
say MyExperiments
, just copy the
Makefile
from the examples directory into
MyExperiments/Makefile
, and change its line
COCOA_ROOT=..
with the full path (no ~
) for CoCoALib-XX
, for
example
COCOA_ROOT=/Users/bigatti/CoCoALib-0.99
In particular ex-empty.C
is a useful starting point: just make a
copy of it into MyExperiments/MyFirstProgram.C
and put your
code in the function void program()
under the line
// Put your code here.
Then compile it and run it as above:
make MyFirstProgram ./MyFirstProgram
CoCoALib comes with a collection of hand-written descriptions of its capabilities as well as a collection of example programs showing how to use many of the features of the library. The hope is that the example programs (plus perhaps a little intelligent guesswork) will suffice to answer most questions about CoCoALib. The hand-written documentation is intended to be more thorough: so less guesswork is needed, but you may have to plough through lots of tedious text to find the detail you're looking for.
The hand-written documentation is split into many files: generally there is one file of documentation for each implementation file in the source code. Furthermore, each file comprises three sections:
This documentation is in the CoCoALib directory doc/txt/
, and
converted into html (doc/html/
) and LaTeX (doc/tex/
) using
txt2tags
.
A template file fo adding to this documentation and some basic
instructions for txt2tags
are
in the file doc/txt/empty.txt.
We have tried to give CoCoALib a natural interface, but this has not always been possible. Here are the main problem areas:
The use of the hat symbol (^) to denote exponentiation is very widespread.
CoCoALib does not allow this you must use the function power
instead.
Why not? Because it would be too easy to write misleading code, i.e.
valid code which does not compute what you would expect. Here is a simple
example: 3*x^2
is interpreted by the compiler as (3*x)^2
. Unfortunately
there is no way to make the C++ compiler use the expected interpretation.
The C++ language is not designed to compute directly with unlimited
integers or with exact rational numbers; special types (namely BigInt
and
BigRat
) to handle these sorts of values have been added as part of CoCoALib
(with the real work being done by the GMP library). Nevertheless the user
has to be wary of several pitfalls where code which looks correct at first
glance does not produce the right answer.
2/3
is valid C++ but is interpreted as an integer division
giving result 0
; instead the rational must be constructed like
this BigRat(2,3)
.
n = 99...99;
(with 99 nines) will
probably not even compile because of an error about "integer
constant too big"; instead such a large value must be handled
directly by CoCoALib in a call like convert(n, "99...99");
where
the variable n
has already been declared to be of type BigInt
or
BigRat
.
BigInt
but the computations will be much slower than with machine integers.
If you are quite sure that large values can never occur then it is
fine to use machine integers; otherwise use unlimited integers.