1[section:issues Known Issues, and TODO List] 2 3Predominantly this is a TODO list, or a list of possible 4future enhancements. Items labeled "High Priority" effect 5the proper functioning of the component, and should be fixed 6as soon as possible. Items labeled "Medium Priority" are 7desirable enhancements, often pertaining to the performance 8of the component, but do not effect it's accuracy or functionality. 9Items labeled "Low Priority" should probably be investigated at 10some point. Such classifications are obviously highly subjective. 11 12If you don't see a component listed here, then we don't have any known 13issues with it. 14 15[h4 tgamma] 16 17* Can the __lanczos be optimized any further? (low priority) 18 19[h4 Incomplete Beta] 20 21* Investigate Didonato and Morris' asymptotic expansion for large a and b 22(medium priority). 23 24[h4 Inverse Gamma] 25 26* Investigate whether we can skip iteration altogether if the first approximation 27is good enough (Medium Priority). 28 29[h4 Polynomials] 30 31* The Legendre and Laguerre Polynomials have surprisingly different error 32rates on different platforms, considering they are evaluated with only 33basic arithmetic operations. Maybe this is telling us something, or maybe not 34(Low Priority). 35 36[h4 Elliptic Integrals] 37 38* [para Carlson's algorithms (mainly R[sub J]) are somewhat prone to 39internal overflow/underflow when the arguments are very large or small. 40The homogeneity relations:] 41[para R[sub F](ka, kb, kc) = k[super -1/2] R[sub F](a, b, c)] 42[para and] 43[para R[sub J](ka, kb, kc, kr) = k[super -3/2] R[sub J](a, b, c, r)] 44[para could be used to sidestep trouble here: provided the problem domains 45can be accurately identified. (Medium Priority).] 46* There are a several other integrals: Bulirsch's ['el] functions that could 47be implemented using Carlson's integrals (Low Priority). 48* The integrals K(k) and E(k) could be implemented using rational 49approximations (both for efficiency and accuracy), 50assuming we can find them. (Medium Priority). 51 52[h4 Owen's T Function] 53 54There is a problem area at arbitrary precision when ['a] is very close to 1. However, note that 55the value for ['T(h, 1)] is well known and easy to compute, and if we replaced the 56['a[super k]] terms in series T1, T2 or T4 by ['(a[super k] - 1)] then we would have the 57difference between ['T(h, a)] and ['T(h, 1)]. Unfortunately this doesn't improve the 58convergence of those series in that area. It certainly looks as though a new series in terms 59of ['(1-a)[super k]] is both possible and desirable in this area, but it remains elusive at present. 60 61[h4 Statistical distributions] 62 63* Student's t Perhaps switch to normal distribution 64as a better approximation for very large degrees of freedom? 65 66[h4 Feature Requests] 67 68The following table lists distributions that are found in other packages 69but which are not yet present here, the more frequently the distribution 70is found, the higher the priority for implementing it: 71 72[table 73[[Distribution][R][Mathematica 6][NIST][Regress+][Matlab]] 74 75[/3 votes:] 76[[Geometric][X][X][-][-][X]] 77 78[/2 votes:] 79[[Multinomial][X][-][-][-][X]] 80[[Tukey Lambda][X][-][X][-][-]] 81[[Half Normal / Folded Normal][-][X][-][X][-]] 82[[Chi][-][X][-][X][-]] 83[[Gumbel][-][X][-][X][-]] 84[[Discrete Uniform][-][X][-][-][X]] 85[[Log Series][-][X][-][X][-]] 86[[Nakagami (generalised Chi)][-][-][-][X][X]] 87 88[/1 vote:] 89[[Log Logistic][-][-][-][-][X]] 90[[Tukey (Studentized range)][X][-][-][-][-]] 91[[Wilcoxon rank sum][X][-][-][-][-]] 92[[Wincoxon signed rank][X][-][-][-][-]] 93[[Non-central Beta][X][-][-][-][-]] 94[[Maxwell][-][X][-][-][-]] 95[[Beta-Binomial][-][X][-][-][-]] 96[[Beta-negative Binomial][-][X][-][-][-]] 97[[Zipf][-][X][-][-][-]] 98[[Birnbaum-Saunders / Fatigue Life][-][-][X][-][-]] 99[[Double Exponential][-][-][X][-][-]] 100[[Power Normal][-][-][X][-][-]] 101[[Power Lognormal][-][-][X][-][-]] 102[[Cosine][-][-][-][X][-]] 103[[Double Gamma][-][-][-][X][-]] 104[[Double Weibul][-][-][-][X][-]] 105[[Hyperbolic Secant][-][-][-][X][-]] 106[[Semicircular][-][-][-][X][-]] 107[[Bradford][-][-][-][X][-]] 108[[Birr / Fisk][-][-][-][X][-]] 109[[Reciprocal][-][-][-][X][-]] 110 111[/0 votes but useful anyway?] 112[[Kolmogorov Distribution][-][-][-][-][-]] 113] 114 115Also asked for more than once: 116 117* Add support for interpolated distributions, possibly combine with numeric 118integration and differentiation. 119* Add support for bivariate and multivariate distributions: most especially the normal. 120* Add support for the log of the cdf and pdf: 121this is mainly a performance optimisation since we can avoid 122some special function calls for some distributions 123by returning the log of the result. 124 125[endsect] [/section:issues Known Issues, and Todo List] 126 127[/ 128 Copyright 2006, 2010 John Maddock and Paul A. Bristow. 129 Distributed under the Boost Software License, Version 1.0. 130 (See accompanying file LICENSE_1_0.txt or copy at 131 http://www.boost.org/LICENSE_1_0.txt). 132] 133 134