def solve1_update(J,nsite,override=True,C2parity=None,h=0.):
'''Get and store the eigen vectors and eigen values for ground state.'''
model=IsingModel(J=J,h=h,nsite=nsite)
spaceconfig=SpinSpaceConfig([2,1])
H_serial=model.H_serial
expander=RGHGen(spaceconfig=spaceconfig,H=H_serial,evolutor_type='null')
t0=time.time()
H=get_H(expander)
Emin,EV=eigsh(H,k=2,which='SA')
t1=time.time()
print 'The Ground State Energy for %s: %s, Elapse %s.'%(model,Emin,t1-t0)
print 'FIN - CORE:%s'%RANK
for i in xrange(2):
suffix='%s_%s.dat'%(model.get_str(),i)
filename_mps='data/mps_'+suffix
filename_eng='data/eng_'+suffix
mps=state2MPS(EV[:,i],sitedim=2,l=0)
mps.save(filename_mps)
savetxt(filename_eng,Emin)
def solve1(J,target_block,nsite,override=True,C2parity=None,h=0.):
'''Get and store the eigen vectors and eigen values for ground state.'''
model=IsingModel(J=J,h=h,nsite=nsite)
suffix='%s_%s.dat'%(model.get_str(),target_block)
filename_mps='data/mps_'+suffix
filename_eng='data/eng_'+suffix
if not override and os.path.isfile(filename_mps):
Ei=loadtxt(filename_eng)[0]
return Ei,MPS.load(filename_mps)
spaceconfig=SpinSpaceConfig([2,1])
H_serial=model.H_serial
expander=RGHGen(spaceconfig=spaceconfig,H=H_serial,evolutor_type='masked')
t0=time.time()
dmrgegn=DMRGEngine(hgen=expander,tol=1e-7,reflect=False,eigen_solver='JD') #we can not use reflect here, because SOC do not meet reflection condition!
dmrgegn.use_U1_symmetry(model.qnumber,target_block=target_block)
Emin,mps=dmrgegn.run_finite(endpoint=(5,'<-',0),maxN=[10,25,50,70,70,70,70],tol=1e-8)
t1=time.time()
print 'The Ground State Energy for %s: %s, Elapse %s.'%(model,Emin,t1-t0)
print 'FIN - CORE:%s'%RANK
mps.save(filename_mps)
savetxt(filename_eng,Emin)
return Emin,mps
