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New break distribution

`newknots = newknt(f,newl) newknt(f) [...,distfn] = newknt(...) `

`newknots = newknt(f,newl) `
returns the knot sequence whose interior knots cut the basic interval
of `f` into `newl` pieces, in such
a way that a certain piecewise linear monotone function related to
the high derivative of `f` is equidistributed.

The intent is to choose a knot sequence suitable to the fine
approximation of a function *g* whose rough approximation
in `f` is assumed to contain enough information
about *g* to make this feasible.

`newknt(f) ` uses for `newl` its
default value, namely the number of polynomial pieces in `f`.

`[...,distfn] = newknt(...) `
also returns, in `distfn`, the ppform of that piecewise
linear monotone function being equidistributed.

If the error in the least-squares approximation `sp` to
some data `x,y` by a spline of order `k` seems
uneven, you might try for a more equitable distribution of knots by
using

spap2(newknt(sp),k,x,y);

For another example, see the last part of the example "Solving an ODE by Collocation".

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