π€ AI Summary
This work investigates the ability of linear codes in the analog domain to detect or localize large anomalous errors while tolerating small perturbations. To this end, it introduces the novel concept of a βheight profile,β which precisely characterizes a codeβs performance across error magnitudes and reveals its intrinsic connection to code structure. By leveraging optimization models, extremal combinatorial formulations, and geometric interpretations, the study establishes multiple equivalent characterizations of the height profile, thereby overcoming the limitations of classical minimum-distance analysis. Combining linear programming, combinatorial optimization, and structural properties of generator matrices, the paper develops explicit computational methods for several code families and quantitatively uncovers the relationship between the Ξ/Ξ΄ ratio and the number of correctable anomalies.
π Abstract
In recent work, it has been shown that maintaining reliability in analog vector--matrix multipliers can be modeled as the following coding problem. Vectors in $\mathbb{R}^k$ are encoded into codewords of a linear $[n,k,d]$ code $C$ over $\mathbb{R}$. For prescribed positive reals $\delta<\Delta$, additive errors of magnitude at most $\delta$ are tolerable and need no handling, yet outlying errors of magnitude greater than $\Delta$ are to be located or detected. The trade-off between the ratio $\Delta/\delta$ and the number of outlying errors that can be handled is determined by the height profile of $C$; as such, the height profile provides a finer description of the error handling capability of $C$, compared to the minimum distance $d$, which only determines the number of correctable errors. This work contains a further study of the notion of the height profile. Several characterizations of the height profile are presented, thereby yielding methods for computing it. The starting point is formulating this computation as an optimization problem that is solved by a set of linear programs. This, in turn, leads to a combinatorial characterization of the height profile as a maximum (or max--min) over a certain finite set of codewords of $C$. Moreover, this characterization is shown to have a simple geometric interpretation when the columns of the generator matrix of $C$ all have the same $L_2$ norm. Through examples of several code families, it is demonstrated how the results herein can be used to compute the height profile explicitly.