Bisection method
Define the midpoint m2 between xmin and m1 and the midpoint m3 between m1 and xmax, such that
Repeat until the value scale is defined with sufficient accuracy
Value measurement techniques
v(m1) = 0.5·v(xmin) + 0.5 · v(xmax) = 0.5
v(m2) = 0.5·v(xmin) + 0.5·v(m1) = 0.25v(m3) = 0.5·v(m1) + 0.5·v(xmax) = 0.75