Description of the main changes between versions 1.38 and 1.39

In addition to the new programs and improvements described below, bugs
have been corrected and improvements have been made. See the file Changes for 
details. 

The use of a few functions may have been changed, so your old GP or Pari 
programs may have to be slightly modified accordingly. These modifications are
preceded by the mention WARNING below.

1) Elementary functions

a) New programs

b) Improvements

For the 68k versions, the small functions such as typ(), lg(), etc... have been
replaced by macros (idea due to D. Grayson), which speeds up by 8%.

2) Transcendental functions

a) New programs

b) Improvements

3) Arithmetic functions

a) New programs

quaddisc (discriminant of a quadratic field).

b) Improvements

4) Functions related to elliptic curves

a) New programs

b) Improvements

5) Functions related to number fields

a) New programs

signunit (find the signs of the real embeddings of the fundamental units).

b) Improvements

The integral basis finding algorithm included in early releases of version 1.38
was a bugged version of Round 4. This is now corrected, and also considerably
sped up through the combined use of Round 4 and Dedekind's test (thanks are
due to P. Letard). This single modification improves by up to 20% the speed of
gp<testin.

In 1.38, the buchxxx programs still contained numerous bugs. This has
been corrected (more hidden bugs may still remain!). The buchxxx programs
have been considerably improved, and can be 10 times faster than before.

IMPORTANT WARNING: the last component (number of relations) in all the 
buchxxx programs has now been removed (the programs takes care of it). Please
modify your old GP programs accordingly.

The isprincipal function should now be able to handle any ideals, and not only
those which split on the factor base after reduction.

6) Polynomials and power series

a) New programs

b) Improvements

7) Linear algebra

a) New programs

b) Improvements

8) Sums, products, etc...

a) New programs

b) Improvements

9) Plotting functions

a) New programs

b) Improvements

10) Programming

a) New programs

allocatemem (allocate a new stack size without waiting for the stack doubling
mechanism).

b) Improvements

The SIGBUS and SIGSEGV signals are now caught. This means that if a bus error
or segmentation fault occurs, you get back in GP (or the calling program)
in principle without losing previous accumulated results. However, beware that
since such an event occurred, this means that there was a bug somewhere hence
that some variables MAY have been corrupted. So be careful afterwards.

Under GP, the output (whether printed or not) is now be automatically
simplified by default to the simplest type (this feature can be turned off and
on by the command \y). Intermediate GP results are NOT simplified.

Under GP, there is a debug level (which by default is at zero) which can
be set by the command \g. Some messages (in French) are printed if the level
is sufficiently high.

For library mode, all error and warning messages are now sent to the global 
file errfile (initialized to stderr), which can be changed as desired.

11) Documentation and coding

a) New style and platforms

b) Improvements