The commercial software CLC Genomics Workbench has a feature called K-means/K-medoids clustering which partitions genes showing similar expression trends over different sampes or over a time course into different gene clusters, which are likely to be co-regulated.
Thanks, but I have a profile of gene expression (all genes that involve in cold stress) by RNA seq and i want to find co-expression genes in this profile. i do not have time series for my study.