This paper studies the computation of error and correct decoding probability exponents in channel coding and lossy source coding. For channel coding, we show that the recently proposed algorithm of Tridenski and Zamir for computing strong converse exponent has the attractive property that the objective function alternately takes the forms appearing in Arimoto's and Dueck and K\"orner's exponents. Because of this property, the convergence of the algorithm directly implies the match of the two exponents. Then, we consider a special case of Tridenski et al.'s generalized algorithm of that has not been examined in depth. We show that the objective function of this algorithm also has the interesting property that it takes the forms of Dueck and K\"orner's exponent and another representation of the strong converse exponent derived by Arimoto's algorithm. This particular case is important because the objective function in this case can be used to prove that the Gallager and Csisz\'ar and K\"orner error exponents agree.63 For lossy source coding, we propose two new algorithms for computing the Csisz\'ar and K\"orner's strong converse exponent. We also define a function similar to Blahut's error exponent with a negative slope parameter for source coding. We show that one of the proposed algorithms has the property that the objective function alternately takes the forms of Csisz\'ar and K\"orner's exponent and the newly defined exponent function. The convergence of the algorithm proves that the new exponent function coincides with the Csisz\'ar and K\"orner exponent. We also prove that Arimoto algorithm for computing error exponent of lossy source coding can work for negative $\rho \ge -1$ and thus can be used to compute the new exponent function. Computation of Arikan and Merhav's guessing exponent is also discussed.
翻译:本文研究频道编码和丢失源编码中的错误和解码概率指数的计算。 对于频道编码, 我们显示最近建议的 Tridenski 和Zamir 用于计算强烈反反推推推的算法具有一种有吸引力的属性, 目标函数会轮流采用Arimoto 和 Dueck 和 K\\ orner 的推算中出现的表格式。 由于此属性, 算法的合并直接意味着两个推算器的匹配 。 然后, 我们考虑一个特例 特里登斯基 和 Al. 的常规算法, 这个特例尚未在深度中检查。 我们显示, 这个算法的客观算法也具有令人感兴趣的属性, 它会以 Deeck 和 K\ “ or or orpent ” 的表格式, 以及另一个表示 Arimotocal exporal expontical compendation 。 我们用两个新的算法来定义 Kral 和 Crental 的 Crental 的 Cral 函数。