source: git/doc/changes_in_singular4.texi @ 0641d2

fieker-DuValspielwiese
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1@comment this file contains the list of new features and difference between Singular 3.* and Singular 4.*
2
3The purpose of this section is to describe new features and changes
4between Singular 3-1-7 and Singular 4.* (formerly known as Spielwiese) both for developers
5and Singular users. In what follows we will refer to the systems as Singular 3 and Singular 4.
6
7@menu
8* Notes for Singular users::
9* Notes for developers::
10* Building Singular::
11@end menu
12
13
14@c ---------------------------------------------------------------------------
15@node Notes for Singular users, Notes for developers, , Singular 3 and Singular 4
16@subsection Notes for Singular users
17@cindex Notes for Singular users
18
19@subsubheading Coefficient rings
20@cindex Coefficient rings
21
22To allow for easy integration of new coefficient rings into Singular, the the way
23coefficient rings are being handled has been redesigned.
24
25In general, the user syntax has not changed, however there are some changes in the behaviour of Singular:
26
27@c table @asis
28@itemize @bullet
29@item setting @code{minpoly} results in changing the current coefficient domain
30and clears all previously defined varaiables of that ring
31
32@item Minor changes in the output of coefficient ring description. Moreover the output of elements of certain rings has been improved (for example, reals).
33
34@item Algebraic and transcendental extensions of rationals and finite fields
35      have been reimplemented. In particular, the heuristics for clearing denominators and factoring out content
36      have been changed. In some cases this leads to a different, mathematically equivalent results of Groebner
37      bases and related computations. For example a Groebner basis element may differ by a unit.
38
39@item Most noteably, due to the redesign of the coefficient rings, if the user sets the minimal polynomial
40      all variables dependent on the current ring are deleted.
41
42@end itemize
43@c @end table
44
45@subsubheading Ring-dependent options
46@cindex Ring-dependent options
47
48Formally global Singular @ref{option} now belong to individual polynomial rings. This includes:
49
50@c table @asis
51@itemize @bullet
52@item @code{intStrategy}
53@item @code{degBound}
54@item @code{multBound}
55????
56@end itemize
57@c @end table
58
59Hence setting these options only affects the current ring. Be aware of this
60when switching between different rings, since the options affect the
61result of various computations (in particular Groebner bases).
62
63@subsubheading New libraries depending on Singular 4
64@cindex New libraries depending on Singular 4
65
66In Singular 4 there several new features are implemented within a
67dynamic module @code{syzextra.so}, not available in Singular 3.
68It implements the low-level functions for Schreyer resolutions and many auxiliary functions.
69The following new libraries @ref{derham_lib}, @ref{schreyer_lib} depend on it:
70
71@c table @asis
72@itemize @bullet
73@item @ref{derham_lib} - computes de Rham cohomology
74@item @ref{schreyer_lib} - computes Schreyer resolution via several approaches. It also serves as a high-level wrapper to the dynamic module @code{syzextra.so}
75@end itemize
76@c @end table
77
78@subsubheading Path names
79@cindex Path names
80
81@c table @asis
82@itemize @bullet
83@item The tree structure of the binary Singular distribution has been changed. The typical tree now looks as follows:
84      *** add tree ***
85
86@item Accordingly Singular search paths (where Singular searches for libraries, dynamic modules, etc.) have been changed. You can display them by calling Singular by @code{Singular -v}.
87
88@item currently, multi-arch installations of Singular 4 aere not possible.
89@end itemize
90@c @end table
91
92@subsubheading Library versioning
93@cindex Library versioning
94
95Due to switching from Subversion to GIT revision control system for the Singular source code,
96library version variables (displayed when loading a library) have changed.
97
98
99@subsubheading New orderings for modules
100@cindex New orderings for modules
101
102The now can assign weights to module components, when defining a monomial ordering. For example
103@smallexample
104ring R = 0, (x,y,z), (am(1,2,3,   10,20,30,40), dp, C);
105deg(x*gen(1));
106@expansion{} 11
107@end smallexample
108
109will assign weights 1,2,3 to x,y,z respectively, and weights 10,20,30,40,0,0,... to
110components of any free module defined over R. This ordering will first sort
111by this weighted degree, then by dp on the ring monomials and then will give priority
112to the large component index.
113
114@subsubheading Future benefits of Singular 4
115@cindex Future benefits of Singular 4
116
117The redesign of Singular will allow us to provide new features in the future, for example:
118
119@c table @asis
120@itemize @bullet
121@item Interpreter type for coefficient rings.
122@item User defined coefficient rings.
123@item Improved syntax for defining polynomial rings.
124@end itemize
125@c @end table
126
127
128
129
130@c ---------------------------------------------------------------------------
131@node Notes for developers, Building Singular, Notes for Singular users, Singular 3 and Singular 4
132@subsection Notes for developers
133@cindex Notes for developers
134
135There has been an entensive process of refactoring, redesign and modularization
136of Singular to facilitate easier maintenance and future development:
137
138@c table @asis
139@itemize @bullet
140@item Build System : automake, libfac has been integrated into Factory
141@item Removed MP (Multi protocol) in favor of SSI links.
142@item Separation/modularization into libraries and packages
143@c add diagram as an image?
144@item For easy integration of new coeffcient rings,
145we defined a generic interface for coefficient
146rings and a supporting framework for making them
147accessible to the user.
148
149In particular we have separated everything related to coeffcient rings into a separate library @code{libcoeffs}.
150
151@end itemize
152@c @end table
153
154
155
156@subsubheading Changes to build system
157@cindex Changes to build system
158
159@c ---------------------------------------------------------------------------
160@node Building Singular, , Notes for developers, Singular 3 and Singular 4
161@subsection Building Singular
162@cindex Building Singular
163
164The user can build and install Singular with the following standard UNIX-like procedure:
165
166@c table @asis
167@itemize @bullet
168@item Download and extract the latest official source package (.tar.gz).
169@item Run the configure script, for instance, @code{./configure}.
170@item Build Singular by running @code{make}.
171@item Install Singular by running @code{make install}.
172@end itemize
173@c @end table
174
175In contrast to Singular 3, there are now many more configuration options.
176
177All possible options for configure can be seen by running the configure script with
178option @code{--help}. On a multicore compute consider running make with the
179option @code{-f [cores]}.
180
181@c ---------------------------------------------------------------------------
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