1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>TODO</title> 5<link rel="stylesheet" href="../../multiprecision.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../index.html" title="Chapter 1. Boost.Multiprecision"> 8<link rel="up" href="../map.html" title="Roadmap"> 9<link rel="prev" href="hist.html" title="History"> 10<link rel="next" href="faq.html" title="FAQ"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="hist.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../map.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="faq.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h3 class="title"> 27<a name="boost_multiprecision.map.todo"></a><a class="link" href="todo.html" title="TODO">TODO</a> 28</h3></div></div></div> 29<p> 30 More a list of what <span class="emphasis"><em>could</em></span> be done, rather than what 31 <span class="emphasis"><em>should</em></span> be done (which may be a much smaller list!). 32 </p> 33<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 34<li class="listitem"> 35 Add back-end support for libdecNumber. 36 </li> 37<li class="listitem"> 38 Add an adaptor back-end for complex number types. 39 </li> 40<li class="listitem"> 41 Add better multiplication routines (Karatsuba, FFT etc) to cpp_int_backend. 42 </li> 43<li class="listitem"> 44 Add assembly level routines to cpp_int_backend. 45 </li> 46<li class="listitem"> 47 Can ring types (exact floating-point types) be supported? The answer 48 should be yes, but someone needs to write it, the hard part is IO and 49 binary-decimal conversion. 50 </li> 51<li class="listitem"> 52 Should there be a choice of rounding mode (probably MPFR specific)? 53 </li> 54<li class="listitem"> 55 We can reuse temporaries in multiple subtrees (temporary caching). 56 </li> 57<li class="listitem"> 58 cpp_dec_float should round to nearest. 59 </li> 60<li class="listitem"> 61 A 2's complement fixed precision int that uses exactly N bits and no 62 more. 63 </li> 64</ul></div> 65<p> 66 Things requested in review: 67 </p> 68<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 69<li class="listitem"> 70 The performances of mp_number<a_trivial_adaptor<float>, false>respect 71 to float and mp_number<a_trivial_adaptor<int>, false> and 72 int should be given to show the cost of using the generic interface (Mostly 73 done, just need to update docs to the latest results). 74 </li> 75<li class="listitem"> 76 Should we provide min/max overloads for expression templates? (Not done 77 - we can't overload functions declared in the std namespace :-( ). 78 </li> 79<li class="listitem"> 80 The rounding applied when converting must be documented (Done). 81 </li> 82<li class="listitem"> 83 Document why we don't abstract out addition/multiplication algorithms 84 etc. (done - FAQ) 85 </li> 86<li class="listitem"> 87 Document why we don't use proto (compile times) (Done). 88 </li> 89<li class="listitem"> 90 We can reuse temporaries in multiple subtrees (temporary caching) Moved 91 to TODO list. 92 </li> 93<li class="listitem"> 94 Emphasise in the docs that ET's may reorder operations (done 2012/10/31). 95 </li> 96<li class="listitem"> 97 Document what happens to small fixed precision cpp_int's (done 2012/10/31). 98 </li> 99<li class="listitem"> 100 The use of bool in template parameters could be improved by the use of 101 an enum class which will be more explicit. E.g <code class="computeroutput"><span class="keyword">enum</span> 102 <span class="keyword">class</span> <span class="identifier">expression_template</span> 103 <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> 104 <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). 105 </li> 106<li class="listitem"> 107 Each back-end should document the requirements it satisfies (not currently 108 scheduled for inclusion: it's deliberately an implementation detail, 109 and "optional" requirements are optimisations which can't be 110 detected by the user). Not done: this is an implementation detail, the 111 exact list of requirements satisfied is purely an optimization, not something 112 the user can detect. 113 </li> 114<li class="listitem"> 115 A backend for an overflow aware integers (done 2012/10/31). 116 </li> 117<li class="listitem"> 118 IIUC convert_to is used to emulate in c++98 compilers C++11 explicit 119 conversions. Could the explicit conversion operator be added on compilers 120 supporting it? (Done 2012/09/15). 121 </li> 122<li class="listitem"> 123 The front-end should make the differences between implicit and explicit 124 construction (Done 2012/09/15). 125 </li> 126<li class="listitem"> 127 The tutorial should add more examples concerning implicit or explicit 128 conversions. (Done 2012/09/15). 129 </li> 130<li class="listitem"> 131 The documentation must explain how move semantics helps in this domain 132 and what the backend needs to do to profit from this optimization. (Done 133 2012/09/15). 134 </li> 135<li class="listitem"> 136 The documentation should contain Throws specification on the mp_number 137 and backend requirements operations. (Done 2012/09/15). 138 </li> 139<li class="listitem"> 140 The library interface should use the noexcept (BOOST_NOEXCEPT, ...) facilities 141 (Done 2012/09/15). 142 </li> 143<li class="listitem"> 144 It is unfortunate that the generic mp_number front end can not make use 145 constexpr as not all the backends can ensure this (done - we can go quite 146 a way). 147 </li> 148<li class="listitem"> 149 literals: The library doesn't provide some kind of literals. I think 150 that the mp_number class should provide a way to create literals if the 151 backend is able to. (Done 2012/09/15). 152 </li> 153<li class="listitem"> 154 The ExpresionTemplate parameter could be defaulted to a traits class 155 for more sensible defaults (done 2012/09/20). 156 </li> 157<li class="listitem"> 158 In a = exp1 op exp2 where a occurs inside one of exp1 or exp2 then we 159 can optimise and eliminate one more temporary (done 2012/09/20). 160 </li> 161</ul></div> 162<h5> 163<a name="boost_multiprecision.map.todo.h0"></a> 164 <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 165 Comments</a> 166 </h5> 167<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 168<li class="listitem"> 169 Make fixed precision orthogonal to Allocator type in cpp_int. Possible 170 solution - add an additional MaxBits template argument that defaults 171 to 0 (meaning keep going till no more space/memory). Done. 172 </li> 173<li class="listitem"> 174 Can ring types (exact floating-point types) be supported? The answer 175 should be yes, but someone needs to write it (Moved to TODO list). 176 </li> 177<li class="listitem"> 178 Should there be a choice of rounding mode (probably MPFR specific)? Moved 179 to TODO list. 180 </li> 181<li class="listitem"> 182 Make the exponent type for cpp_dec_float a template parameter, maybe 183 include support for big-integer exponents. Open question - what should 184 be the default - int32_t or int64_t? (done 2012/09/06) 185 </li> 186<li class="listitem"> 187 Document the size requirements of fixed precision ints (done 2012/09/15). 188 </li> 189<li class="listitem"> 190 Document std lib function accuracy (done 2012/09/15). 191 </li> 192<li class="listitem"> 193 Be a bit clearer on the effects of sign-magnitude representation of cpp_int 194 - min == -max etc - done. 195 </li> 196<li class="listitem"> 197 Document cpp_dec_float precision, rounding, and exponent size (done 2012/09/06). 198 </li> 199<li class="listitem"> 200 Can we be clearer in the docs that mixed arithmetic doesn't work (no 201 longer applicable as of 2012/09/06)? 202 </li> 203<li class="listitem"> 204 Document round functions behaviour better (they behave as in C++11) (added 205 note 2012/09/06). 206 </li> 207<li class="listitem"> 208 Document limits on size of cpp_dec_float (done 2012/09/06). 209 </li> 210<li class="listitem"> 211 Add support for fused multiply add (and subtract). GMP mpz_t could use 212 this (done 2012/09/20). 213 </li> 214</ul></div> 215</div> 216<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 217<td align="left"></td> 218<td align="right"><div class="copyright-footer">Copyright © 2002-2020 John 219 Maddock and Christopher Kormanyos<p> 220 Distributed under the Boost Software License, Version 1.0. (See accompanying 221 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>) 222 </p> 223</div></td> 224</tr></table> 225<hr> 226<div class="spirit-nav"> 227<a accesskey="p" href="hist.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../map.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="faq.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 228</div> 229</body> 230</html> 231
