File: [local] / OpenXM_contrib / pari-2.2 / Attic / TODO (download)
Revision 1.2, Wed Sep 11 07:26:37 2002 UTC (22 years ago) by noro
Branch: MAIN
CVS Tags: RELEASE_1_2_3, RELEASE_1_2_2_KNOPPIX_b, RELEASE_1_2_2_KNOPPIX, RELEASE_1_2_2 Changes since 1.1: +29 -47
lines
Upgraded pari-2.2 to pari-2.2.4.
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This file lists the things that ought to be implemented / fixed. It is
hopelessly incomplete right now, but it's a start. Most items require major
work, and may not be that desireable after all. If you intend to work on
any of these things, have a look at CVS.txt and drop an email to pari-dev.
Priority classification (first column): [subjective and debatable!]
5 as soon as possible
4 should be done
3 nice to have
2 maybe not
1 probably not
0 no
- unclassified
*************************** BUGS (general) ****************************
Unless specified otherwise, examples assume 32bit machine and default precision
5 bnfinit sometimes gives wrong answers because we cheat on the value of
Bach's bound, using 0.3 log^2 D by default, where 0.3 should really be 12
(under GRH). If it's not enough, we compute a subquotient of the classgroup,
i.e junk. Ex:
* setrand(3); bnfinit(y^4 + 1190*y^2 + 1416100).cyc --> [8,2,2,2].
Wrong. The correct structure is [8,4,2].
* setrand(1414185642); bnf = bnfinit(y^4 + 635*y^2 + 403225).reg is twice
the correct value.
5 polgalois(x^8-1864259299553450972214799899167226732549697977945716*x^6+331143259018657601105207922631212331088735421305543663274125986698777318014979969*x^4-2225286541902342283500014249183311190477390*x^2+5);
*** degree too large in tschirn.
4 precision problems in polgalois:
setrand(7);
polgalois(x^8+162644002617632464507038884216211529274267271168000002)
gives wrong result at \p28 [32,-1,17], correct at \p38 [32,-1,15]
4 gcmp/gegal not transitive: [] == 0, [0] == 0, but [0] != []
4 rnfpolred is numerically unstable:
? rnfpolred(nfinit(quadpoly(904,y)),quadray(904,1))
*** division by zero in gdiv, gdivgs or ginv
4 qfbclassno(x < 0) may give a wrong result [e.g x = -2878367]
3 many functions assume MAXVARN is a free variable, yielding bogus
results if the input involves it (only affects library programming).
3 quadclassunit not reliable when fed non fundamental discriminants
(infinite loop [e.g quadclassunit(-352)], wrong result)
3 ellinit over Q_2 doesn't work (AGM loses too much precision)
3 ellpointtoz over Q_p makes no difference between P and -P (corrected over
C by a cheap trick)
3 recursive plot easily fooled. One could split intervals in 3 + make sure
size of neighbouring intervals don't differ too much.
*************************** BUGS (GP specific) ****************************
5 readline: assume a file 'foo' exists, \rf<TAB> --> \foo [\r f<TAB> is OK]
4 changing primelimit from within forprime loop yields unpredictable results
3 after allocatemem() / default(parisize, ...), the rest of the command is
discarded (ends by a longjmp).
2 under GP after an error, memory is only recovered from "entire variables".
Individual components of lists/vectors/matrices are left alone if the
GLOBAL object wasn't modified during the last cycle (i.e only v[x] = ...
occured)
1 sum(i=1,3000, exp(-i^2)) --> overflow in R*R
The "negligible" terms should be neglegted, not overflow because of the
way the computation is done. [ Tough to correct! ]
*************************** DOCUMENTATION ****************************
5 complete/update the tutorial (esp. section 11 and 12)
4 add examples for all functions in Chapter 3
4 separate chapter 4 and 5 and document the innards of PARI (entree,
pariFILE, bloc ...)
2 HTML version (pod ? SGML ? yodl ???)
*************************** MISCELLANEOUS ****************************
5 write decent (specialized) benches
3 switch to autoconf
3 use stat() instead of opendir() to check if a file is a directory.
*************************** ALGORITHMS ****************************
Kernel:
=======
5 check NaN in dbltor and related routines
4 benchmark / profile basic functions and see what needs to be done
4 finish t_REAL Karatsuba and diviiexact
4 inline level0 routines should operate on _limbs_, not on words.
3 FFT for basic types and polynomials (say in A[X], for A = Z, F_q, ...)
2 add support for different multiprecision kernels (a la LiDIA)
Misc:
=====
4 decent finite field package (remove all the nfxxxmodpr functions)
4 rnfkummer (very slow)
4 nfsubfields [use known subfields to discard blocs right away] (current uses
far too much memory)
3 zetak is very inefficient and unable to handle most fields of degree > 8
3 have quadclassunit return bnf structure
3 2-adic initell
3 p-adic ellztopoint
0 graphics: allow FIG output (besides PostScript) [easier to edit!]
[ No: use pstoedit ]
*************************** LIBRARY DESIGN ****************************
4 a system of DEBUGLEVEL classes [e.g \g 5 "LLL" ] (such that the user can
easily define new ones)
4 allow generic functions to process and produce t_SMALL's
4 remove all dependences on types ordering [if (typ(x) < t_POL) ...]
3 remove global variables gpi, geuler: their precision is unpredictable
(at least as much as requested in last const[pi|euler](), possibly much
more). Explicit call to mp[pi|euler] should be required. Will break
existing code...
3 rename library functions following GP names
3 rewrite the generic functions (gadd/gmul/gdiv plus a couple of others) to
use (two-dimensional) table lookups instead of switches
3 introduce "special" types for objects which are really containers and
should be defined by a secondary type (e.g number fields, finite fields,
p-adic fields, elliptic curves, ...). Would keep list of types small
(and fast)
3 better representations for multivariate polynomials
3 type "element in" ([number|finite] field...), "point" on elliptic curve
3 find a way to deal (generically) with "integral object + its content"
Application (e.g): fractional ideals much more efficient.
2 "mute" variables for t_POLMOD. Should have Mod(x,x^2+1) == Mod(y,y^2+1).
2 have some header magic (transparently) prepend some prefix (e.g "pari_")
before all exported functions to prevent name conflicts. Build alias
files for debuggers
*************************** GP DESIGN ****************************
5 remove limitation to 8 arguments for static functions (argvec[9])
4 use divide & conquer approach in string / integer conversions
4 extend forprime(n=a,b,...) so that b can go over primelimit [cut [a,b]
in large intervals, sieve out multiple of small primes there, then use
isprime() on the rest]
3 changevar with explicit (incomplete) permutation. E.g
changevar(p, [x,y], [a,b]) for x -> a, y -> b
add a flag to substitute in succession or in parallel (e.g if a involves y)
3 possibility to save and load a session (variables, functions, defaults)
3 a type t_FILE [current: stream re-opened/flushed/closed after every single
write(): disaster when one wants to write often to the same file]
3 add a possibility to increase the maximal recursion depth (need to
increase the GP process stack: use setrlimit(RLIMIT_STACK,) + fork)
*************************** TOOLS ****************************
4 a script converting prototype to parser code (e.g GEN f(GEN,GEN) --> "GG")
3 a script to translate "legacy" GP code into something using GP2 function
names
3 write an analog of the 'echo' default which would print code as it is
executed, not as it is read
2 write a GP scripts debugger
2 write a GP scripts profiler