def from_fci(ci0, nmoa_nmob, nocca_noccb):
from pyscf import fci
from pyscf.ci.cisd_slow import t2strs
norba, norbb = nmoa_nmob
nocca, noccb = nocca_noccb
nvira = norba - nocca
nvirb = norbb - noccb
t1addra, t1signa = cisd.t1strs(norba, nocca)
t1addrb, t1signb = cisd.t1strs(norbb, noccb)
na = fci.cistring.num_strings(norba, nocca)
nb = fci.cistring.num_strings(norbb, noccb)
ci0 = ci0.reshape(na, nb)
c0 = ci0[0, 0]
c1a = ((ci0[t1addra, 0] * t1signa).reshape(nvira, nocca).T)[::-1]
c1b = ((ci0[0, t1addrb] * t1signb).reshape(nvirb, noccb).T)[::-1]
c2ab = numpy.einsum('i,j,ij->ij', t1signa, t1signb, ci0[t1addra][:,
t1addrb])
c2ab = c2ab.reshape(nvira, nocca, nvirb, noccb).transpose(1, 3, 0, 2)
c2ab = c2ab[::-1, ::-1]
t2addra, t2signa = t2strs(norba, nocca)
c2aa = (ci0[t2addra, 0] * t2signa).reshape(nvira * (nvira - 1) // 2, -1).T
c2aa = _unpack_4fold(c2aa[::-1], nocca, nvira)
t2addrb, t2signb = t2strs(norbb, noccb)
c2bb = (ci0[0, t2addrb] * t2signb).reshape(nvirb * (nvirb - 1) // 2, -1).T
c2bb = _unpack_4fold(c2bb[::-1], noccb, nvirb)
return amplitudes_to_cisdvec(c0, (c1a, c1b), (c2aa, c2ab, c2bb))
def from_fcivec(ci0, norb, nelec, frozen=0):
from pyscf.ci.gcisd import t2strs
if frozen is not 0:
raise NotImplementedError
if isinstance(nelec, (int, numpy.number)):
nelecb = nelec // 2
neleca = nelec - nelecb
else:
neleca, nelecb = nelec
norba = norbb = norb
nocc = nocca, noccb = neleca, nelecb
nvira = norba - nocca
nvirb = norbb - noccb
t1addra, t1signa = cisd.t1strs(norba, nocca)
t1addrb, t1signb = cisd.t1strs(norbb, noccb)
na = cistring.num_strings(norba, nocca)
nb = cistring.num_strings(norbb, noccb)
ci0 = ci0.reshape(na, nb)
c0 = ci0[0, 0]
c1a = ((ci0[t1addra, 0] * t1signa).reshape(nvira, nocca).T)[::-1]
c1b = ((ci0[0, t1addrb] * t1signb).reshape(nvirb, noccb).T)[::-1]
c2ab = numpy.einsum('i,j,ij->ij', t1signa, t1signb, ci0[t1addra][:,
t1addrb])
c2ab = c2ab.reshape(nvira, nocca, nvirb, noccb).transpose(1, 3, 0, 2)
c2ab = c2ab[::-1, ::-1]
t2addra, t2signa = t2strs(norba, nocca)
c2aa = (ci0[t2addra, 0] * t2signa).reshape(nvira * (nvira - 1) // 2, -1).T
c2aa = _unpack_4fold(c2aa[::-1], nocca, nvira)
t2addrb, t2signb = t2strs(norbb, noccb)
c2bb = (ci0[0, t2addrb] * t2signb).reshape(nvirb * (nvirb - 1) // 2, -1).T
c2bb = _unpack_4fold(c2bb[::-1], noccb, nvirb)
return amplitudes_to_cisdvec(c0, (c1a, c1b), (c2aa, c2ab, c2bb))
def to_fci(cisdvec, nmoa_nmob, nocca_noccb):
from pyscf import fci
from pyscf.ci.cisd_slow import t2strs
norba, norbb = nmoa_nmob
nocca, noccb = nocca_noccb
nvira = norba - nocca
nvirb = norbb - noccb
c0, c1, c2 = cisdvec_to_amplitudes(cisdvec, nmoa_nmob, nocca_noccb)
c1a, c1b = c1
c2aa, c2ab, c2bb = c2
t1addra, t1signa = cisd.t1strs(norba, nocca)
t1addrb, t1signb = cisd.t1strs(norbb, noccb)
na = fci.cistring.num_strings(norba, nocca)
nb = fci.cistring.num_strings(norbb, noccb)
fcivec = numpy.zeros((na, nb))
fcivec[0, 0] = c0
fcivec[t1addra, 0] = c1a[::-1].T.ravel() * t1signa
fcivec[0, t1addrb] = c1b[::-1].T.ravel() * t1signb
c2ab = c2ab[::-1, ::-1].transpose(2, 0, 3, 1).reshape(nocca * nvira, -1)
c2ab = numpy.einsum('i,j,ij->ij', t1signa, t1signb, c2ab)
lib.takebak_2d(fcivec, c2ab, t1addra, t1addrb)
if nocca > 1 and nvira > 1:
ooidx = numpy.tril_indices(nocca, -1)
vvidx = numpy.tril_indices(nvira, -1)
c2aa = c2aa[ooidx][:, vvidx[0], vvidx[1]]
t2addra, t2signa = t2strs(norba, nocca)
fcivec[t2addra, 0] = c2aa[::-1].T.ravel() * t2signa
if noccb > 1 and nvirb > 1:
ooidx = numpy.tril_indices(noccb, -1)
vvidx = numpy.tril_indices(nvirb, -1)
c2bb = c2bb[ooidx][:, vvidx[0], vvidx[1]]
t2addrb, t2signb = t2strs(norbb, noccb)
fcivec[0, t2addrb] = c2bb[::-1].T.ravel() * t2signb
return fcivec
def to_fcivec(cisdvec, norb, nelec, frozen=0):
from pyscf.ci.gcisd import t2strs
if isinstance(nelec, (int, numpy.number)):
nelecb = nelec // 2
neleca = nelec - nelecb
else:
neleca, nelecb = nelec
frozena_mask = numpy.zeros(norb, dtype=bool)
frozenb_mask = numpy.zeros(norb, dtype=bool)
if isinstance(frozen, (int, numpy.integer)):
nfroza = nfrozb = frozen
frozena_mask[:frozen] = True
frozenb_mask[:frozen] = True
else:
nfroza = len(frozen[0])
nfrozb = len(frozen[1])
frozena_mask[frozen[0]] = True
frozenb_mask[frozen[1]] = True
# if nfroza != nfrozb:
# raise NotImplementedError
nocca = numpy.count_nonzero(~frozena_mask[:neleca])
noccb = numpy.count_nonzero(~frozenb_mask[:nelecb])
nmo = nmoa, nmob = norb - nfroza, norb - nfrozb
nocc = nocca, noccb
nvira, nvirb = nmoa - nocca, nmob - noccb
c0, c1, c2 = cisdvec_to_amplitudes(cisdvec, nmo, nocc)
c1a, c1b = c1
c2aa, c2ab, c2bb = c2
t1addra, t1signa = cisd.t1strs(nmoa, nocca)
t1addrb, t1signb = cisd.t1strs(nmob, noccb)
na = cistring.num_strings(nmoa, nocca)
nb = cistring.num_strings(nmob, noccb)
fcivec = numpy.zeros((na, nb))
fcivec[0, 0] = c0
fcivec[t1addra, 0] = c1a[::-1].T.ravel() * t1signa
fcivec[0, t1addrb] = c1b[::-1].T.ravel() * t1signb
c2ab = c2ab[::-1, ::-1].transpose(2, 0, 3, 1).reshape(nocca * nvira, -1)
c2ab = numpy.einsum('i,j,ij->ij', t1signa, t1signb, c2ab)
lib.takebak_2d(fcivec, c2ab, t1addra, t1addrb)
if nocca > 1 and nvira > 1:
ooidx = numpy.tril_indices(nocca, -1)
vvidx = numpy.tril_indices(nvira, -1)
c2aa = c2aa[ooidx][:, vvidx[0], vvidx[1]]
t2addra, t2signa = t2strs(nmoa, nocca)
fcivec[t2addra, 0] = c2aa[::-1].T.ravel() * t2signa
if noccb > 1 and nvirb > 1:
ooidx = numpy.tril_indices(noccb, -1)
vvidx = numpy.tril_indices(nvirb, -1)
c2bb = c2bb[ooidx][:, vvidx[0], vvidx[1]]
t2addrb, t2signb = t2strs(nmob, noccb)
fcivec[0, t2addrb] = c2bb[::-1].T.ravel() * t2signb
if nfroza == nfrozb == 0:
return fcivec
assert (norb < 63)
strsa = cistring.gen_strings4orblist(range(norb), neleca)
strsb = cistring.gen_strings4orblist(range(norb), nelecb)
na = len(strsa)
nb = len(strsb)
count_a = numpy.zeros(na, dtype=int)
count_b = numpy.zeros(nb, dtype=int)
parity_a = numpy.zeros(na, dtype=bool)
parity_b = numpy.zeros(nb, dtype=bool)
core_a_mask = numpy.ones(na, dtype=bool)
core_b_mask = numpy.ones(nb, dtype=bool)
for i in range(norb):
if frozena_mask[i]:
if i < neleca:
core_a_mask &= (strsa & (1 << i)) != 0
parity_a ^= (count_a & 1) == 1
else:
core_a_mask &= (strsa & (1 << i)) == 0
else:
count_a += (strsa & (1 << i)) != 0
if frozenb_mask[i]:
if i < nelecb:
core_b_mask &= (strsb & (1 << i)) != 0
parity_b ^= (count_b & 1) == 1
else:
core_b_mask &= (strsb & (1 << i)) == 0
else:
count_b += (strsb & (1 << i)) != 0
sub_strsa = strsa[core_a_mask & (count_a == nocca)]
sub_strsb = strsb[core_b_mask & (count_b == noccb)]
addrsa = cistring.strs2addr(norb, neleca, sub_strsa)
addrsb = cistring.strs2addr(norb, nelecb, sub_strsb)
fcivec1 = numpy.zeros((na, nb))
fcivec1[addrsa[:, None], addrsb] = fcivec
fcivec1[parity_a, :] *= -1
fcivec1[:, parity_b] *= -1
return fcivec1