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\documentclass{article}
\usepackage{axiom}
\begin{document}
\title{\$SPAD/src/input streams.input}
\author{The Axiom Team}
\maketitle
\begin{abstract}
\end{abstract}
\eject
\tableofcontents
\eject
\section{License}
<<license>>=
--Copyright The Numerical Algorithms Group Limited 1991.
@
<<*>>=
<<license>>
)clear all
)set streams calculate 5
)set streams showall on
--at least 5 stream elements will be evaluated
--the stream of integers starting at 1
a := [i for i in 1..]
b := [i+1 for i in a]
--select the 20th element
b.20
--the first 20 elements of b (and a) are evaluated
b
a
--the first 10 elements of a
first(a,10)
--all except the first 10 elements of a
rest(a,10)
--the stream of odd integers
[i for i in a | odd? i]
--combining two streams
c := [[i,j] for i in a for j in b]
-- selecting the first from each pair
[first i for i in c]
)set streams calculate 10
--concat(a,b) concatenates streams a and b, better if a is finite
concat([i for i in a while i<7],a)
concat(a,a)
upto:NNI->STREAM INT
upto n == first(a,n)
d := [upto n for n in a]
--concat flattens a stream of streams into a one level stream
concat d
--the sum of a finite stream
reduce(0,_+$INT,first(a,10))
--a stream of cumulative sums
scan(0,_+$INT,a)
scan(0,_+$INT,[2*i-1 for i in a])
ff:(LIST INT)->(LIST INT)
ff(x)==[x.1+x.2,x.1]
--generate(f,x) operates on an A->A function f and an initial A, x
--to produce the stream x,f x,f(f x),...
fibs := generate(ff,[1,1])
--first([first i for i in fibs], 100)
mt:SQMATRIX(2,INT) := matrix [[1,2],[3,4]]
mplm:SQMATRIX(2,INT)->SQMATRIX(2,INT)
mplm x == x*mt
generate(mplm,mt)
@
\eject
\begin{thebibliography}{99}
\bibitem{1} nothing
\end{thebibliography}
\end{document}
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