I ran Sequenza for one tumor sample with the matched normal control. I obtained purity 0.9 and ploidy 3 for the tumor. When I saw the chromosome plots, I found that regions showing depth ratio close to 1 were set to copy number 3. In my understanding, copy numbers for depth ratio 1 should be 2 because normal control would have diploid. Is there a relation between copy number setting and ploidy?