Fix falsely reporting some numbers as not positive in pca_plot
Fix falsely reporting some numbers as not positive in pca_plot

nsh87/receptormarker,catterbu/receptormarker,catterbu/receptormarker,daniel0128/receptormarker,catterbu/receptormarker,daniel0128/receptormarker,catterbu/receptormarker,nsh87/receptormarker,daniel0128/receptormarker,catterbu/receptormarker,daniel0128/receptormarker,nsh87/receptormarker,daniel0128/receptormarker,daniel0128/receptormarker,nsh87/receptormarker,daniel0128/receptormarker,nsh87/receptormarker