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<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_multiprecision.map.todo"></a><a class="link" href="todo.html" title="TODO">TODO</a>
</h3></div></div></div>
<p>
More a list of what <span class="emphasis"><em>could</em></span> be done, rather than what
<span class="emphasis"><em>should</em></span> be done (which may be a much smaller list!).
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
Add back-end support for libdecNumber.
</li>
<li class="listitem">
Add an adaptor back-end for complex number types.
</li>
<li class="listitem">
Add better multiplication routines (Karatsuba, FFT etc) to cpp_int_backend.
</li>
<li class="listitem">
Add assembly level routines to cpp_int_backend.
</li>
<li class="listitem">
Can ring types (exact floating point types) be supported? The answer
should be yes, but someone needs to write it, the hard part is IO and
binary-decimal conversion.
</li>
<li class="listitem">
Should there be a choice of rounding mode (probably MPFR specific)?
</li>
<li class="listitem">
We can reuse temporaries in multiple subtrees (temporary caching).
</li>
<li class="listitem">
cpp_dec_float should round to nearest.
</li>
<li class="listitem">
A 2's complement fixed precision int that uses exactly N bits and no
more.
</li>
</ul></div>
<p>
Things requested in review:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
The performances of mp_number<a_trivial_adaptor<float>, false>respect
to float and mp_number<a_trivial_adaptor<int>, false> and
int should be given to show the cost of using the generic interface (Mostly
done, just need to update docs to the latest results).
</li>
<li class="listitem">
Should we provide min/max overloads for expression templates? (Not done
- we can't overload functions declared in the std namespace :-( ).
</li>
<li class="listitem">
The rounding applied when converting must be documented (Done).
</li>
<li class="listitem">
Document why we don't abstract out addition/multiplication algorithms
etc. (done - FAQ)
</li>
<li class="listitem">
Document why we don't use proto (compile times) (Done).
</li>
<li class="listitem">
We can reuse temporaries in multiple subtrees (temporary caching) Moved
to TODO list.
</li>
<li class="listitem">
Emphasise in the docs that ET's may reorder operations (done 2012/10/31).
</li>
<li class="listitem">
Document what happens to small fixed precision cpp_int's (done 2012/10/31).
</li>
<li class="listitem">
The use of bool in template parameters could be improved by the use of
an enum class which will be more explicit. E.g <code class="computeroutput"><span class="keyword">enum</span>
<span class="keyword">class</span> <span class="identifier">expression_template</span>
<span class="special">{</span><span class="identifier">disabled</span><span class="special">,</span> <span class="identifier">enabled</span><span class="special">};</span> <span class="keyword">enum</span> <span class="keyword">class</span> <span class="identifier">sign</span>
<span class="special">{</span><span class="keyword">unsigned</span><span class="special">,</span> <span class="keyword">signed</span><span class="special">};</span></code> (Partly done 2012/09/15, done 2012/10/31).
</li>
<li class="listitem">
Each back-end should document the requirements it satisfies (not currently
scheduled for inclusion: it's deliberately an implementation detail,
and "optional" requirements are optimisations which can't be
detected by the user). Not done: this is an implementation detail, the
exact list of requirements satisfied is purely an optimization, not something
the user can detect.
</li>
<li class="listitem">
A backend for an overflow aware integers (done 2012/10/31).
</li>
<li class="listitem">
IIUC convert_to is used to emulate in c++98 compilers C++11 explicit
conversions. Could the explicit conversion operator be added on compilers
supporting it? (Done 2012/09/15).
</li>
<li class="listitem">
The front-end should make the differences between implicit and explicit
construction (Done 2012/09/15).
</li>
<li class="listitem">
The tutorial should add more examples concerning implicit or explicit
conversions. (Done 2012/09/15).
</li>
<li class="listitem">
The documentation must explain how move semantics helps in this domain
and what the backend needs to do to profit from this optimization. (Done
2012/09/15).
</li>
<li class="listitem">
The documentation should contain Throws specification on the mp_number
and backend requirements operations. (Done 2012/09/15).
</li>
<li class="listitem">
The library interface should use the noexcept (BOOST_NOEXCEPT, ...) facilities
(Done 2012/09/15).
</li>
<li class="listitem">
It is unfortunate that the generic mp_number front end can not make use
constexpr as not all the backends can ensure this (done - we can go quite
a way).
</li>
<li class="listitem">
literals: The library doesn't provide some kind of literals. I think
that the mp_number class should provide a way to create literals if the
backend is able to. (Done 2012/09/15).
</li>
<li class="listitem">
The ExpresionTemplate parameter could be defaulted to a traits class
for more sensible defaults (done 2012/09/20).
</li>
<li class="listitem">
In a = exp1 op exp2 where a occurs inside one of exp1 or exp2 then we
can optimise and eliminate one more temporary (done 2012/09/20).
</li>
</ul></div>
<h5>
<a name="boost_multiprecision.map.todo.h0"></a>
<span class="phrase"><a name="boost_multiprecision.map.todo.pre_review_comments"></a></span><a class="link" href="todo.html#boost_multiprecision.map.todo.pre_review_comments">Pre-Review
Comments</a>
</h5>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
Make fixed precision orthogonal to Allocator type in cpp_int. Possible
solution - add an additional MaxBits template argument that defaults
to 0 (meaning keep going till no more space/memory). Done.
</li>
<li class="listitem">
Can ring types (exact floating point types) be supported? The answer
should be yes, but someone needs to write it (Moved to TODO list).
</li>
<li class="listitem">
Should there be a choice of rounding mode (probably MPFR specific)? Moved
to TODO list.
</li>
<li class="listitem">
Make the exponent type for cpp_dec_float a template parameter, maybe
include support for big-integer exponents. Open question - what should
be the default - int32_t or int64_t? (done 2012/09/06)
</li>
<li class="listitem">
Document the size requirements of fixed precision ints (done 2012/09/15).
</li>
<li class="listitem">
Document std lib function accuracy (done 2012/09/15).
</li>
<li class="listitem">
Be a bit clearer on the effects of sign-magnitude representation of cpp_int
- min == -max etc - done.
</li>
<li class="listitem">
Document cpp_dec_float precision, rounding, and exponent size (done 2012/09/06).
</li>
<li class="listitem">
Can we be clearer in the docs that mixed arithmetic doesn't work (no
longer applicable as of 2012/09/06)?
</li>
<li class="listitem">
Document round functions behaviour better (they behave as in C++11) (added
note 2012/09/06).
</li>
<li class="listitem">
Document limits on size of cpp_dec_float (done 2012/09/06).
</li>
<li class="listitem">
Add support for fused multiply add (and subtract). GMP mpz_t could use
this (done 2012/09/20).
</li>
</ul></div>
</div>
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<td align="right"><div class="copyright-footer">Copyright © 2002-2013 John Maddock and Christopher Kormanyos<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
</p>
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