Advanced Portfolio with a start date

[Haowen Liu]

Hi all,

Currently Advanced Portfolio report has a Date config that's end date 
for the report. Is there a way to specify the start date from which to 
start calculating returns?

If not, would GNC maintainers be open to a patch adding such support? 
Any suggestions on how would I go about implementing it? The Advanced 
Portfolio implementation is here IIUC: 
https://github.com/Gnucash/gnucash/blob/stable/gnucash/report/reports/standard/advanced-portfolio.scm.

Haowen