How to calculate the shadow bias in shadow maps(PSSM)

akira32

I implement the Parallel-Split Shadow Maps into my scene.
My scene seems to have the moire patterns. I think that I must to calculate the shadow bias individually in each split?
But I cannot find the algorithm and article of shadow bias. Colud somebody ever find the shadow bias's data?

qrli

I think the bias should be the same, because the shadow map volumes has the same resolution in depth axis but different resolutions in parallel axes.