functions in roots.i - m

             fmin= mnbrent(f, x0, x1, x2)  
          or fmin= mnbrent(f, x0, x1, x2, xmin)  
          or fmin= mnbrent(f, x0, x1, x2, xmin, xerr)  
 
     returns the minimum of the function F (of a single argument x),  
     given three points X0, X1, and X2 such that F(X1) is less than  
     either F(X0) or F(X2), and X1 is between X0 and X2.  If the  
     XMIN argument is provided, it is set to the x value which  
     produced FMIN.  If XERR is supplied, the search stops when  
     a fractional error of XERR in x is reached; note that XERR  
     smaller than the square root of the machine precision (or  
     omitted) will cause convergence to machine precision in FMIN.  
     The algorithm is Brent's method - a combination of inverse  
     parabolic interpolation and golden section search - as adapted  
     from Numerical Recipes Ch. 10 (Press, et. al.).  
interpreted function, defined at i/roots.i   line 233  

             fmax= mxbrent(f, x0, x1, x2)  
          or fmax= mxbrent(f, x0, x1, x2, xmax)  
          or fmax= mxbrent(f, x0, x1, x2, xmax, xerr)  
 
     returns the maximum of the function F (of a single argument x),  
     given three points X0, X1, and X2 such that F(X1) is greater than  
     either F(X0) or F(X2), and X1 is between X0 and X2.  If the  
     XMAX argument is provided, it is set to the x value which  
     produced FMAX.  If XERR is supplied, the search stops when  
     a fractional error of XERR in x is reached; note that XERR  
     smaller than the square root of the machine precision (or  
     omitted) will cause convergence to machine precision in FMAX.  
     The algorithm is Brent's method - a combination of inverse  
     parabolic interpolation and golden section search - as adapted  
     from Numerical Recipes Ch. 10 (Press, et. al.).  
interpreted function, defined at i/roots.i   line 208