f90 files to use cubic spline with tension

also test program: cbspltest.f90

To obtain module:

f90 -c prec_rkind.f90
f90 -c interpos.f90

Then, using system (on the suns) LAPACK double precision routines:
f90 interpos.o cbspltest.f90 -xlic_lib=sunperf
a.out > output.m

If LAPACKroutines not available, they are in varlaprout2.f90 varlaprout.f90:
f90 varlaprout2.f90 varlaprout.f90 interpos.o cbspltest.f90  (in that order)
a.out > output.m

in matlab:
output  % gets variables: in, out, outsplibnd
plot(in(:,1),in(:,2),'*-')
hold on
plot(out(:,1),out(:,2),'r-')
plot(outsplibnd(:,1),outsplibnd(:,2),'g--')
plot(out(:,1),out(:,3),'r-') % etc