I am using the latest Julia version ITensors.
1.I defined an Index with QN. When I set "dir = In", the Index is not ordered, e.g. qn(s(2)) = QN("N",4,5). When I set "dir = Neither", qn(s(j)) always gives QN("N",0,5). Is this a bug?
s = Index([QN(("N",i,5)) => 1 for i = 0:4];dir = ITensors.Arrow(0))
BTW, the direction name "Out", "In" conflict with Out and In in Jupyter Notebook.
2.I wanted to svd an ITensor with QN, but it says "In
setindex!, the element you are trying to set is in a block that does not have the same flux as the other blocks of the ITensor. You may be trying to create an ITensor that does not have a well defined quantum number flux."
dim0 = 4
s = Index([QN(("N",i,dim0))=>1 for i = 0:(dim0-1)];dir = ITensors.Arrow(1))
#s = Index(dim0)
l = addtags(s,"left")
r = addtags(s,"right")
u = addtags(s,"up")
d = addtags(s,"down")
A = emptyITensor(l,r,u,d)
for sl = 1:dim0, sd = 1:dim0, sr = 1:dim0, su = 1:dim0
#if sl+sd == sr+su || abs(sl+sd-sr-su) == dim0
if val(qn(l(sl))+qn(d(sd))-qn(r(sr))-qn(u(su)),"N") == 0
A[l(sl),r(sr),u(su),d(sd)] = 1
Am I doing wrong?