 The performance is measured by the distance between the consumption rate and a fraction 0\leq\lambda\leq 1 of the historical consumption maximum.
<meaning-changed>  The performance is measured by the distance between the consumption rate and a fraction 0\leq\lambda\leq 1 of the historical consumption maximum.
 The performance is measured by the difference between the non-negative consumption rate and a fraction 0\leq\lambda\leq 1 of the historical consumption maximum.