Hi all : I'm a user of "cgh" package. Here's a question about "sign". As to help on "sign": sign = +1 is used to detect polysomy (regions of copy number change increase) in test:control logratios. sign = -1 is used ?C inverting the sign of the logratios ?C to detect deletions (regions of copy number decrease). I wanna know whether my opinion about "sign" is correct: If I think ratio > 2 and ratio < 0.5 are considered as copy number increase and decrease respectively. So the corresponding sign is log2(2):+1 and log2(0.5):-1 respectively. If I think ratio > 1.5 and ratio < 0.67 are considered as copy number increase and decrease respectively. So the corresponding sign is log2(1.5):+0.585 and log2(1/1.5):-0.585 respectively. I wanna know whether I'm right on "sign". If not ,how can I use "sign" according to different "ratio" threshold of copy number increase and decrease? Thanks a lot for your help! My best regards