I'm trying to generate a heatmap for almost 15,000 genes expression data across different samples. But they are grouped into clusters based on their similar expression across samples and I wanna represent the clusters vs samples rather than the genes vs samples (since they're like 15,000 genes) in the heatmap. Is there a way to do it? I know the melt function in R would help me plot the heat map in the way I want but I'm not sure how to implement it. I expect the heatmap to look something like this [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4489295/figure/F2/]. Thanks in advance.