Gradient Decoding Revisited

Modern coding applications, including dirty paper coding and information hiding, hinge critically on a classical 'general decoding problem,' known to be NP hard. Various attempts to find good solutions at reasonable complexity can be traced throughout the decades, most recently with attempts to achieve the rate-distortion bound in code word quantization. Here we take a step back to examine two computationally simple procedures in this direction: gradient decoding and a simple yet surprisingly effective variant on belief propagation that we dub truthiness propagation.