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dft_tools/fortran/dmftproj/symmetrize_mat.f
2013-07-23 20:55:29 +02:00

293 lines
14 KiB
Fortran

c ******************************************************************************
c
c TRIQS: a Toolbox for Research in Interacting Quantum Systems
c
c Copyright (C) 2011 by L. Pourovskii, V. Vildosola, C. Martins, M. Aichhorn
c
c TRIQS is free software: you can redistribute it and/or modify it under the
c terms of the GNU General Public License as published by the Free Software
c Foundation, either version 3 of the License, or (at your option) any later
c version.
c
c TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
c WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
c FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
c details.
c
c You should have received a copy of the GNU General Public License along with
c TRIQS. If not, see <http://www.gnu.org/licenses/>.
c
c *****************************************************************************/
SUBROUTINE symmetrize_mat(Dmat,orbit,norbit)
C %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
C %% %%
C %% This subroutine applies the symmetry operations to the %%
C %% density matrices stored in Dmat and puts the resulting %%
C %% density matrices into the local coordinate system. %%
C %% %%
C %% This version can be used for SO computations. %%
C %% %%
C %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
C Definition of the variables :
C ----------------------------
USE common_data
USE projections
USE symm
USE reps
IMPLICIT NONE
INTEGER :: norbit
TYPE(matrix), DIMENSION(nsp,norbit) :: Dmat
COMPLEX(KIND=8),DIMENSION(:,:,:,:), ALLOCATABLE :: sym_dmat
COMPLEX(KIND=8),DIMENSION(:,:), ALLOCATABLE :: tmp_mat
COMPLEX(KIND=8):: ephase
TYPE(orbital), DIMENSION(norbit) :: orbit
INTEGER :: isym, iorb, iatom, jorb, is, is1, l, i, m
INTEGER :: isrt, jatom, imult, asym
C
C =========================================
C Computation of the symmetrized matrices :
C =========================================
C
iorb=1
C Initialization of the iorb index.
DO WHILE (iorb.lt.(norbit+1))
C The use of the while-loop was motivated by the idea of studying
C all the orbitals iorb associated to a same atomic sort isrt together.
C At the end, the index iorb is incremented by nmult(isrt) so that the
C following studied orbitals are associated to another atomic sort.
l=orbit(iorb)%l
isrt=orbit(iorb)%sort
C
C -----------------------------------------------------------------------------------
C The s-orbitals are a particular case of a "non-mixing" basis and are treated here :
C -----------------------------------------------------------------------------------
IF (l==0) THEN
C The table sym_dmat will store the symmetrized value of the density matrices of Dmat
C associated to a same atomic sort isrt.
ALLOCATE(sym_dmat(1,1,nsp,1:nmult(isrt)))
sym_dmat=0.d0
C Its size is nmult(isrt) because symmetry operations can transform the representants
C of a same atomic sort one into another.
C
C Loop on the representants of the atomic sort isrt
DO imult=0,nmult(isrt)-1
iatom=orbit(iorb+imult)%atom
C Loop on the symmetry operations of the system
DO isym=1,nsym
DO is=1,nsp
ALLOCATE(tmp_mat(1,1))
C If the calculation uses spin-polarized input files, the application of the symmetry operation
C depends on the field srot%timeinv.
IF(ifSP.AND.srot(isym)%timeinv) THEN
C In this case (spin-polarized computation), the symmetry operation is block-diagonal in spin-space but
C the time reversal operator is included.
tmp_mat(1,1)=CONJG(Dmat(is,iorb+imult)%mat(1,1))
C because of the antiunitarity of the operator, the conjugate of Dmat must be use
ELSE
tmp_mat(1,1)=Dmat(is,iorb+imult)%mat(1,1)
ENDIF
C
C Definition of the index where the transformed Dmat will be stored. [jorb = R[isym](iorb)]
jorb=srot(isym)%perm(iatom)-iatom+(imult+1)
C
C Computation of the phase factors in the case of a SO computation :
C ------------------------------------------------------------------
C For up/up and dn/dn blocks, no phase factor is needed.
ephase=1.d0
C For the up/dn block, initialisation of the phase factor
IF(is==3) THEN
ephase=EXP(CMPLX(0d0,srot(isym)%phase))
C if srot%timeinv = .TRUE. , phase= g-a = 2pi+(alpha-gamma) and ephase = exp(+i(g-a)) = exp(+i(alpha-gamma))
C if srot%timeinv = .FALSE., phase= a+g = 2pi-(alpha+gamma) and ephase = exp(+i(a+g)) = exp(-i(alpha+gamma))
ENDIF
C For the dn/up block, initialisation of the phase factor
IF(is==4) THEN
ephase=EXP(CMPLX(0d0,-srot(isym)%phase))
C if srot%timeinv = .TRUE. , phase= g-a = 2pi+(alpha-gamma) and ephase = exp(-i(g-a)) = exp(-i(alpha-gamma))
C if srot%timeinv = .FALSE., phase= a+g = 2pi-(alpha+gamma) and ephase = exp(-i(a+g)) = exp(+i(alpha+gamma))
ENDIF
C
C Application of the symmetry operation which changes iorb in jorb=R[isym](iorb) :
C --------------------------------------------------------------------------------
C That's why the result is stored in the jorb section of sym_dmat.
sym_dmat(1,1,is,jorb)=
= sym_dmat(1,1,is,jorb)+tmp_mat(1,1)*ephase
DEALLOCATE(tmp_mat)
ENDDO ! End of the is loop
ENDDO ! End of the isym loop
ENDDO ! End of the imult loop
C
C Renormalization of the symmetrized density matrices :
C -----------------------------------------------------
IF (nsym.gt.0) THEN
DO imult=0,nmult(isrt)-1
DO is=1,nsp
Dmat(is,iorb+imult)%mat(1,1)=
& sym_dmat(1,1,is,imult+1)/nsym
ENDDO
ENDDO
ENDIF
DEALLOCATE(sym_dmat)
C Incrementation of the iorb index (for the while loop)
iorb=iorb+nmult(isrt)
C
C -----------------------------------------------------------------------------------------------------
C If the basis representation needs a complete spinor rotation approach (matrices of size 2*(2*l+1) ) :
C -----------------------------------------------------------------------------------------------------
ELSEIF (reptrans(l,isrt)%ifmixing) THEN
C The table sym_dmat will store the symmetrized value of the density matrices of Dmat
C associated to a same atomic sort isrt.
ALLOCATE(sym_dmat(1:2*(2*l+1),1:2*(2*l+1),1,1:nmult(isrt)))
sym_dmat=0.d0
C Its size is nmult(isrt) because symmetry operations can transform the representants
C of a same atomic sort one into another.
C
C Loop on the representants of the atomic sort isrt
DO imult=0,nmult(isrt)-1
iatom=orbit(iorb+imult)%atom
C Loop on the symmetry operations of the system
DO isym=1,nsym
ALLOCATE(tmp_mat(1:2*(2*l+1),1:2*(2*l+1)))
C We use the complete spin-space representation, so no trick on indices is necessary.
tmp_mat(1:2*(2*l+1),1:2*(2*l+1))=
& Dmat(1,iorb+imult)%mat(1:2*(2*l+1),1:2*(2*l+1))
C If the calculation is spin-polarized, the symmetry operator is antiunitary.
IF(ifSP.AND.srot(isym)%timeinv) THEN
tmp_mat(1:2*(2*l+1),1:2*(2*l+1))=
& CONJG(tmp_mat(1:2*(2*l+1),1:2*(2*l+1)))
ENDIF
C Definition of the index where the transformed Dmat will be stored. [jorb = R[isym](iorb)]
jorb=srot(isym)%perm(iatom)-iatom+(imult+1)
C Application of the symmetry operation :
C ---------------------------------------
C The transformation is : srot%rotrep.tmpmat(iorb).inverse(sort%rotrep) = Dmat(jorb)
C or in other words, if R is a simple symmetry D(R[isym]) tmpmat(iorb) D(inverse(R[isym])) = Dmat(R[isym](iorb))
C if R is multiplied by Theta D(R[isym]) tmpmat(iorb)* D(inverse(R[isym]))* = Dmat(R[isym](iorb))
tmp_mat(1:2*(2*l+1),1:2*(2*l+1))=
= MATMUL(tmp_mat(1:2*(2*l+1),1:2*(2*l+1)),
& TRANSPOSE(CONJG(srot(isym)%rotrep(l,isrt)
% %mat(1:2*(2*l+1),1:2*(2*l+1)) )) )
sym_dmat(1:2*(2*l+1),1:2*(2*l+1),1,jorb)=
= sym_dmat(1:2*(2*l+1),1:2*(2*l+1),1,jorb)+
+ MATMUL( srot(isym)%rotrep(l,isrt)
% %mat(1:2*(2*l+1),1:2*(2*l+1)) ,
& tmp_mat(1:2*(2*l+1),1:2*(2*l+1)))
DEALLOCATE(tmp_mat)
ENDDO ! End of the isym loop
ENDDO ! End of the imult loop
C Renormalization of the symmetrized density matrices :
C -----------------------------------------------------
IF (nsym.gt.0) THEN
DO imult=0,nmult(isrt)-1
Dmat(1,iorb+imult)%mat(1:2*(2*l+1),1:2*(2*l+1))=
= sym_dmat(1:2*(2*l+1),1:2*(2*l+1),1,imult+1)/nsym
ENDDO
ENDIF
DEALLOCATE(sym_dmat)
C Incrementation of the iorb index (for the while loop)
iorb=iorb+nmult(isrt)
C
C ----------------------------------------------------------------------------------------------
C If the basis representation can be reduce to the up/up block (matrices of size (2*l+1) only) :
C ----------------------------------------------------------------------------------------------
ELSE
C The table sym_dmat will store the symmetrized value of the density matrices of Dmat
C associated to a same atomic sort isrt.
ALLOCATE(sym_dmat(-l:l,-l:l,nsp,1:nmult(isrt)))
sym_dmat=0.d0
C Its size is nmult(isrt) because symmetry operations can transform the representants
C of a same atomic sort one into another.
C
C Loop on the representants of the atomic sort isrt
DO imult=0,nmult(isrt)-1
iatom=orbit(iorb+imult)%atom
C Loop on the symmetry operations of the system
asym=0
DO isym=1,nsym
DO is=1,nsp
ALLOCATE(tmp_mat(-l:l,-l:l))
C If the calculation uses spin-polarized input files, the application of the symmetry operation
C depends on the field srot%timeinv.
IF(ifSP.AND.srot(isym)%timeinv) THEN
C In this case (spin-polarized computation), the symmetry operation is block-diagonal in spin-space but
C the time reversal operatot is included.
tmp_mat(-l:l,-l:l)=CONJG(
& Dmat(is,iorb+imult)%mat(-l:l,-l:l))
C because of antiunitarity of the operator, the conjugate of Dmat must be use
ELSE
tmp_mat(-l:l,-l:l)=
& Dmat(is,iorb+imult)%mat(-l:l,-l:l)
ENDIF
C
C Definition of the index where the transformed Dmat will be stored. [jorb = R[isym](iorb)]
jorb=srot(isym)%perm(iatom)-iatom+(imult+1)
C
C Computation of the phase factors in the case of a SO computation :
C ------------------------------------------------------------------
C For up/up and dn/dn blocks, no phase factor is needed.
ephase=1.d0
C For the up/dn block, initialisation of the phase factor
IF(is==3) THEN
ephase=EXP(CMPLX(0d0,srot(isym)%phase))
C if srot%timeinv = .TRUE. , phase= g-a = 2pi+(alpha-gamma) and ephase = exp(+i(g-a)) = exp(+i(alpha-gamma))
C if srot%timeinv = .FALSE., phase= a+g = 2pi-(alpha+gamma) and ephase = exp(+i(a+g)) = exp(-i(alpha+gamma))
ENDIF
C For the dn/up block, initialisation of the phase factor
IF(is==4) THEN
ephase=EXP(CMPLX(0d0,-srot(isym)%phase))
C if srot%timeinv = .TRUE. , phase= g-a = 2pi+(alpha-gamma) and ephase = exp(-i(g-a)) = exp(-i(alpha-gamma))
C if srot%timeinv = .FALSE., phase= a+g = 2pi-(alpha+gamma) and ephase = exp(-i(a+g)) = exp(+i(alpha+gamma))
ENDIF
C
C Application of the symmetry operation which changes iorb in jorb :
C ------------------------------------------------------------------
C The transformation is : srot%rotrep.tmpmat(iorb).inverse(sort%rotrep) = Dmat(jorb)
C or in other words, if R is a simple symmetry D(R[isym]) tmpmat(iorb) D(inverse(R[isym])) = Dmat(R[isym](iorb))
C if R is multiplied by T D(R[isym]) tmpmat(iorb)* D(inverse(R[isym]))* = Dmat(R[isym](iorb))
tmp_mat(-l:l,-l:l)=
= MATMUL(tmp_mat(-l:l,-l:l),
& TRANSPOSE(CONJG( srot(isym)
& %rotrep(l,isrt)%mat(-l:l,-l:l) )) )
sym_dmat(-l:l,-l:l,is,jorb)=
= sym_dmat(-l:l,-l:l,is,jorb)+
+ MATMUL(srot(isym)%rotrep(l,isrt)%mat(-l:l,-l:l),
& tmp_mat(-l:l,-l:l) )*ephase
DEALLOCATE(tmp_mat)
ENDDO ! End of the is loop
ENDDO ! End of the isym loop
ENDDO ! End of the imult loop
C
C Renormalization of the symmetrized density matrices :
C -----------------------------------------------------
IF (nsym.gt.0) THEN
DO imult=0,nmult(isrt)-1
DO is=1,nsp
Dmat(is,iorb+imult)%mat(-l:l,-l:l)=
= sym_dmat(-l:l,-l:l,is,imult+1)/(nsym-asym)
ENDDO
ENDDO
ENDIF
DEALLOCATE(sym_dmat)
C Incrementation of the iorb index (for the while loop)
iorb=iorb+nmult(isrt)
ENDIF ! End of the type basis if-then-else
C
ENDDO ! End of the while(iorb) loop
C
C
C =============================================================
C Application of the time reversal operation if paramagnetism :
C =============================================================
C If the system is paramagnetic, the magnetic group of the system
C is a type II Shubnikov group and time-reveral symmetry must be added
C to achieve the complete symmetrization.
IF (.not.ifSP) THEN
CALL add_timeinv(Dmat,orbit,norbit)
END IF
C
RETURN
END