mlmpfr

OCaml bindings for MPFR.

mlmpfr provides mpfr_float, an immutable data structure that contains a
mpfr_t number, as well as an optional ternary value, as provided by (and
described in) the MPFR library.

A few distinctions are made from the original C library:

• the mpfr_ prefix is ommited for all functions;

• mpfr_init* and mpfr_set* functions are not provided in order to implement
  these bindings with respect to the functional paradigm (and immutability).
  Consequently, mpfr_clear* functions are not provided too, and so, the
  garbage collector is in charge of memory management. See initilization
  functions;

• functions managing the following C types are not supported: unsigned long int, uintmax_t, intmax_t, float, long double, __float128,
  _Decimal64, _Decimal128, mpz_t, mpq_t, and mpf_t. Except for
  mpfr_sqrt_ui and mpfr_fac_ui which are partially supported in the range of
  the positive values of an OCaml signed integer. In fact, only the OCaml native
  types (signed 64-bit int, 64-bit float, and string) are supported. Thus,
  all functions named with *_[su]i* or *_d* are renamed here with *_int*
  or *_float*, respectively;

• bindings to functions mpfr_*printf, mpfr_*random*, mpfr_get_patches,
  mpfr_buildopt_*, and, macros MPFR_VERSION*, mpfr_round_nearest_away are
  not implemented. Everything else has been ported!

build and install

Building mlmpfr.4.1.0 depends on dune (an
OCaml build system), ocaml version >= 4.04, and MPFR library version 4.1.0
(see footnote for building older mlmpfr releases). Basically you just need to
install mlmpfr via the opam package manager, which will triggers all the
dependencies (such as dune for example).

• From sources (github repo or with latest
  releases): in mlmpfr main
  directory, on branch master or release_410. Make sure that you have the
  proper MPFR library version installed on your system because mlmpfr won't
  check for it (see utils/mpfr_version.c).

dune build @install @runtest
dune install

Use --prefix <path> to set another path (the default path is the parent of the
directory where ocamlc was found).

• From opam, targeting latest release (see opam info to list available
  releases):

opam install mlmpfr
# `opam remove mlmpfr` to remove the package.

documentation

Documentation depends on package odoc.

dune build @doc

then, see _build/default/_doc/_html/index.html. An online version
is available here.

usage

For example, let example.ml as follows:

module M = Mlmpfr

let _ =
  let op = M.make_from_float (~-. 1. /. 3.) in
  Printf.printf "%s\n" (M.get_formatted_str (M.cos op))

Compile the above code with:

$ ocamlfind ocamlc -package mlmpfr -linkpkg example.ml -o a.out

will result in:

$ ./a.out
9.449569463147377e-01

You can also use dune with

$ dune exec examples/example.exe
9.449569463147377e-01

Note: install an older release of mlmpfr

Older releases of mlmpfr (3.1.6, 4.0.0, and 4.0.1) depend on
oasis, an obsolete build system replaced
by dune since mlmpfr.4.0.2. Use opam if you need to install an older release
of mlmpfr, as for example:

opam install mlmpfr.3.1.6

Or, you can build it from the sources, as for example from branch release_316:

oasis setup
./configure --enable-tests
make
make test
make install
# `make uninstall` to remove mlmpfr library.

opam packages mlmpfr.4.0.0 and mlmpfr.4.0.1 also exist and are suitable for
MPFR 4.0.0 and 4.0.1 versions.

Note: build examples with an older release of mlmpfr

You'll need to link with -cclib -lmpfr (along with ocamlopt) if you are
using released versions of mlmpfr (as the ones provided by opam), since mlmpfr
wasn't linked with mpfr by default before.