2.1 Risa and Asir
Risa is the name of whole libraries of a computer algebra system
which is under development at FUJITSU LABORATORIES LIMITED.
The structure of Risa is as follows.
The basic algebraic engine
This is the part which performs basic algebraic operations,
such as arithmetic operations, to algebraic objects, e.g., numbers and
polynomials, which are already converted into internal forms.
It exists, like ‘libc.a’ of UNIX, as a library of ordinary UNIX system.
The algebraic engine is written mainly in C language and
partly in assembler.
It serves as the basic operation part of Asir, a standard
language interface of Risa.
Risa employs, as its memory management component (the memory
manager), a free software distributed by Boehm (
It is proposed by
[Boehm,Weiser], and developed by Boehm and
The memory manager has a memory allocator which automatically
reclaims garbages, i.e., allocated but unused memories,
and refreshes them for further use.
The algebraic engine gets all its necessary memories through the memory
Asir is a standard language interface of Risa’s algebraic
engine. It is one of the possible language interfaces, because
one can develop one’s own language interface easily on Risa
Asir is an example of such language interfaces.
Asir has very similar syntax and semantics as C language.
Furthermore, it has a debugger that provide a subset of commands of
dbx, a widely used debugger of C language.
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