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chapter xiii, example 3 . test of optimal spline interpolation routine
c on titanium heat data .
c from * a practical guide to splines * by c. de boor
calls titand,splopt(bsplvb,banfac/slv),splint(*),bvalue(interv)
c
c lenscr = (n-k)(2k+3)+5k+3 is the length of scrtch required in
c splopt .
c parameter n=12,ntitan=49,k=5,npk=17,lenscr=119
c integer i,iflag,ipick(n),ipicki,lx,nmk
c real a(n),gtitan(ntitan),gtau(ntitan),scrtch(lenscr),t(npk),tau(n)
c * ,x(ntitan)
real bvalue
integer i,iflag,ipick(12),ipicki,lx,nmk
real a(12),gtitan(49),gtau(49),scrtch(119),t(17),tau(12)
* ,x(49)
data n,k /12,5/
data ipick /1,5,11,21,27,29,31,33,35,40,45,49/
call titand ( x, gtitan, lx )
do 10 i=1,n
ipicki = ipick(i)
tau(i) = x(ipicki)
10 gtau(i) = gtitan(ipicki)
call splopt ( tau, n, k, scrtch, t, iflag )
if (iflag .gt. 1) stop
call splint ( tau, gtau, t, n, k, scrtch, a, iflag )
if (iflag .gt. 1) stop
do 20 i=1,lx
gtau(i) = bvalue ( t, a, n, k, x(i), 0 )
20 scrtch(i) = gtitan(i) - gtau(i)
print 620,(i,x(i),gtitan(i),gtau(i),scrtch(i),i=1,lx)
620 format(41h i, data point, data, interpolant, error//
2 (i3,f8.0,f10.4,f9.4,e11.3))
nmk = n-k
print 621,(i,t(k+i),i=1,nmk)
621 format(///16h optimal knots =/(i5,f15.9))
stop
end
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