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chapter x. example 2. plotting the pol,s which make up a b-spline
c from * a practical guide to splines * by c. de boor
calls bsplvb
c
integer ia,left
real biatx(4),t(11),values(4),x
c knot sequence set here....
data t / 4*0.,1.,3.,4.,4*6. /
do 20 ia=1,40
x = float(ia)*.2 - 1.
do 10 left=4,7
call bsplvb ( t, 4, 1, x, left, biatx )
c
c according to bsplvb listing, biatx(.) now contains value
c at x of polynomial which agrees on the interval (t(left),
c t(left+1) ) with the b-spline b(left-4 + . ,4,t) . hence,
c biatx(8-left) now contains value of that polynomial for
c b(left-4 +(8-left) ,4,t) = b(4,4,t) . since this b-spline
c has support (t(4),t(8)), it makes sense to run left = 4,
c ...,7, storing the resulting values in values(1),...,
c values(4) for later printing.
c
10 values(left-3) = biatx(8-left)
20 print 620, x, values
620 format(f10.1,4f20.8)
stop
end
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