@include version.texi
+@dircategory Mathematics
@direntry
* ginac: (ginac). C++ library for symbolic computation.
@end direntry
This is a tutorial that documents GiNaC @value{VERSION}, an open
framework for symbolic computation within the C++ programming language.
-Copyright (C) 1999-2007 Johannes Gutenberg University Mainz, Germany
+Copyright (C) 1999-2008 Johannes Gutenberg University Mainz, Germany
Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
@page
@vskip 0pt plus 1filll
-Copyright @copyright{} 1999-2007 Johannes Gutenberg University Mainz, Germany
+Copyright @copyright{} 1999-2008 Johannes Gutenberg University Mainz, Germany
@sp 2
Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
@section License
The GiNaC framework for symbolic computation within the C++ programming
-language is Copyright @copyright{} 1999-2007 Johannes Gutenberg
+language is Copyright @copyright{} 1999-2008 Johannes Gutenberg
University Mainz, Germany.
This program is free software; you can redistribute it and/or
warning levels. If omitted, it defaults to @option{-g
-O2}.@footnote{The @command{configure} script is itself generated from
the file @file{configure.ac}. It is only distributed in packaged
-releases of GiNaC. If you got the naked sources, e.g. from CVS, you
+releases of GiNaC. If you got the naked sources, e.g. from git, you
must generate @command{configure} along with the various
@file{Makefile.in} by using the @command{autoreconf} utility. This will
require a fair amount of support from your local toolchain, though.}
have a look at the most important classes in the class hierarchy and
some of the relations among the classes:
+@ifnotinfo
@image{classhierarchy}
+@end ifnotinfo
+@ifinfo
+<PICTURE MISSING>
+@end ifinfo
The abstract classes shown here (the ones without drop-shadow) are of no
interest for the user. They are used internally in order to avoid code
anything useful with it.
@cindex @code{get_value()}
-@cindex @code{get_dimension()}
+@cindex @code{get_dim()}
The methods
@example
ex idx::get_value();
-ex idx::get_dimension();
+ex idx::get_dim();
@end example
return the value and dimension of an @code{idx} object. If you have an index
with @samp{e.k}
directly supplied in the second form of the procedure. In the first form
the Clifford unit @samp{e.k} is generated by the call of
-@code{clifford_unit(mu, metr, rl)}. The previous code may be rewritten
-with the help of @code{lst_to_clifford()} as follows
+@code{clifford_unit(mu, metr, rl)}.
+@cindex pseudo-vector
+If the number of components supplied
+by @code{v} exceeds the dimensionality of the Clifford unit @code{e} by
+1 then function @code{lst_to_clifford()} uses the following
+pseudo-vector representation:
+@tex
+$v^0 {\bf 1} + v^1 e_0 + v^2 e_1 + ... + v^{n+1} e_n$
+@end tex
+@ifnottex
+@samp{v~0 ONE + v~1 e.0 + v~2 e.1 + ... + v~[n+1] e.n}
+@end ifnottex
+
+The previous code may be rewritten with the help of @code{lst_to_clifford()} as follows
@example
@{
@ifnottex
@samp{v = (v~0, v~1, ..., v~n)}
@end ifnottex
-such that
+such that the expression is either vector
@tex
$e = v^0 c_0 + v^1 c_1 + ... + v^n c_n$
@end tex
@ifnottex
@samp{e = v~0 c.0 + v~1 c.1 + ... + v~n c.n}
@end ifnottex
-with respect to the given Clifford units @code{c} and with none of the
-@samp{v~k} containing Clifford units @code{c} (of course, this
+or pseudo-vector
+@tex
+$v^0 {\bf 1} + v^1 e_0 + v^2 e_1 + ... + v^{n+1} e_n$
+@end tex
+@ifnottex
+@samp{v~0 ONE + v~1 e.0 + v~2 e.1 + ... + v~[n+1] e.n}
+@end ifnottex
+with respect to the given Clifford units @code{c}. Here none of the
+@samp{v~k} should contain Clifford units @code{c} (of course, this
may be impossible). This function can use an @code{algebraic} method
-(default) or a symbolic one. With the @code{algebraic} method the @samp{v~k} are calculated as
+(default) or a symbolic one. With the @code{algebraic} method the
+@samp{v~k} are calculated as
@tex
$(e c_k + c_k e)/c_k^2$. If $c_k^2$
@end tex
and @code{false} if it doesn't. If used in the second form, the actual
subexpressions matched by the wildcards get returned in the @code{repls}
object as a list of relations of the form @samp{wildcard == expression}.
-If @code{match()} returns false, the state of @code{repls} is undefined.
-For reproducible results, the list should be empty when passed to
-@code{match()}, but it is also possible to find similarities in multiple
-expressions by passing in the result of a previous match.
+If @code{match()} returns false, @code{repls} remains unmodified.
The matching algorithm works as follows:
placing character strings in algebraic expressions (this is not very useful,
but it's just an example). This class will be a direct subclass of
@code{basic}. You can use this sample implementation as a starting point
-for your own classes.
+for your own classes @footnote{The self-contained source for this example is
+included in GiNaC, see the @file{doc/examples/mystring.cpp} file.}.
The code snippets given here assume that you have included some header files
as follows:
and exponent and some atomic leaves of symbols and numbers in this
fashion:
+@ifnotinfo
@image{repnaive}
+@end ifnotinfo
+@ifinfo
+<PICTURE MISSING>
+@end ifinfo
@cindex pair-wise representation
However, doing so results in a rather deeply nested tree which will
having a numeric exponent and a possibly complicated base, the tree
becomes much more flat:
+@ifnotinfo
@image{reppair}
+@end ifnotinfo
+@ifinfo
+<PICTURE MISSING>
+@end ifinfo
The number @code{3} above the symbol @code{d} shows that @code{mul}
objects are treated similarly where the coefficients are interpreted as
@math{2*d^3*(4*a+5*b-3)}:
@end ifnottex
+@ifnotinfo
@image{repreal}
+@end ifnotinfo
+@ifinfo
+<PICTURE MISSING>
+@end ifinfo
@cindex radical
This also allows for a better handling of numeric radicals, since
git://www.ginac.de / ginac.git / blobdiff