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chapter x. example 3. construction and evaluation of the pp-representat-
c ion of a b-spline.
c from * a practical guide to splines * by c. de boor
calls bsplpp(bsplvb),ppvalu(interv)
c
integer ia,l
real bcoef(7),break(5),coef(4,4),scrtch(4,4),t(11),value,x
real ppvalu
c set knot sequence t and b-coeffs for b(4,4,t) ....
data t / 4*0.,1.,3.,4.,4*6. /, bcoef / 3*0.,1.,3*0. /
c construct pp-representation ....
call bsplpp ( t, bcoef, 7, 4, scrtch, break, coef, l )
c
c as a check, evaluate b(4,4,t) from its pp-repr. on a fine mesh.
c the values should agree with (some of) those generated in
c example 2 .
do 20 ia=1,40
x = float(ia)*.2 - 1.
value = ppvalu ( break, coef, l, 4, x, 0 )
20 print 620, x, value
620 format(f10.1,f20.8)
stop
end
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