 <CODE>minbrack</CODE> will search outside this interval if
necessary. The bracket consists of three points (in increasing order)
such that <CODE>f(brmid) < f(brmin)</CODE> and <CODE>f(brmid) < f(brmax)</CODE>.
<CODE>fa</CODE> is the value of the function at <CODE>a</CODE>: it is included to
avoid unnecessary function evaluations in the optimization routines.
The return value <CODE>numevals</CODE> is the number of function evaluations
in <CODE>minbrack</CODE>.

<p><CODE>minbrack(f, a, b, fa, p1, p2,