- Comp-phys-alps-users - lists.phys.ethz.ch

matrixelement=?
by Mateusz Łącki 30 Nov '11

30 Nov '11

Dear All, I have found here: http://alps.comp-phys.org/mediawiki/index.php/Tutorials:MeasureHOWTO a way to measure an observable (while working with QMC code) which is related to the basis in which we measure by some simple formula: sqrt (N). But i still have some question regarding implementing a non-standard situation. I would not like to go into really ugly details, so I have created a self contained example: I understood that: symbols "N" that appearing in that example are labels of quantum numbers defining the basis: if basis was enumerated by a few quantum numbers then the config should look like this: <SITEBASIS name="boson"> <QUANTUMNUMBER name="S" min="0" max="b1"/> <QUANTUMNUMBER name="C" min="0" max="b2"/> <OPERATOR name="Milka" matrixelement="1"> <CHANGE quantumnumber="S" change="-1"/> <CHANGE quantumnumber="C" change="1"/> </OPERATOR> </SITEBASIS> In this case operator "Milka" creates one bar of chocolate using one unit of sugar? Another issue is what makes a correct expression? I suppose that parsing of these things is done by "expression" binary. Which functions are supporter by this parser? sqrt(N) is supported but BesselJ(N) may not be, I also saw different examples of random number generators - matrixelement="random_gaussian(1)" (or sth like that). The other question: if matrix elements are not constant, a simple function but "conditional" in nature: Milka_{(S1,C1), (S2,C2)} = 1 is \lambda(S1,C1,S2,C2) is true and -7 otherwise then I suppose: <SITEBASIS name="boson"> <QUANTUMNUMBER name="S" min="0" max="b1"/> <QUANTUMNUMBER name="C" min="0" max="b2"/> <OPERATOR name="Milka" matrixelement=" f(S1,C1,S2,C2)-7*(1-f(S1,C1,S2,C2))"> <CHANGE ...> </OPERATOR> </SITEBASIS> will do provided f evaluates to 1,0 iff \lambda is true,false for any C1,C2,S2,S1. Is there a way to introduce "if" construct inside the matrixelement? Regards, Mateusz Lacki

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FindLapack.cmake - proposed change
by Mateusz Łącki 29 Nov '11

29 Nov '11

Dear All, I heve succesfull debugged cmake's failure to properly set up my mkl. I use the newest Intel suite there is, and I had lots of errors when trying to link with it. In config/FindLapack.cmake there was: SET(MKL_PATHS $ENV{MKL_HOME}/lib/em${QMC_BITS}t $ENV{MKL_HOME}/lib/${QMC_BITS} $ENV{MKL_HOME}/lib ${MKL_PATHS} ) after changing to: $ENV{MKL_HOME}/lib/intel64${QMC_BITS} $ENV{MKL_HOME}/lib/em${QMC_BITS}t $ENV{MKL_HOME}/lib/${QMC_BITS} $ENV{MKL_HOME}/lib ${MKL_PATHS} ) as well as: STRING(REGEX MATCHALL "[-][L]([^ ;])+" MKL_PATH_WITH_PREFIX "$ENV{MKL}") should be modified to make it possible to build successfully when MKL does not contain "-L" just before the path First change is needed because new mkl versions contain libs in $MKL/lib/intel64 (here $MKL also does not include -L) Regards, Mateusz Lacki

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alps-2.0.2 compile error
by Tadeusz Wasiutyński 29 Nov '11

29 Nov '11

Dears, After successful installation of alps-2.0.2 on my desktop (Scientific Linux 6.1) I moved to the cluster with RedHat5(el5) with gcc 4.1.2 and python 2.4.3 . Make produced error: Linking CXX executable compactrun ../src/boost/libboost.so: undefined reference to `pthread_create' ../src/boost/libboost.so: undefined reference to `pthread_key_create' ../src/boost/libboost.so: undefined reference to `pthread_getspecific' ../src/boost/libboost.so: undefined reference to `pthread_once' ../src/boost/libboost.so: undefined reference to `pthread_join' ../src/boost/libboost.so: undefined reference to `pthread_setspecific' ../src/boost/libboost.so: undefined reference to `pthread_detach' collect2: ld returned 1 exit status make[2]: *** [tool/compactrun] Error 1 make[1]: *** [tool/CMakeFiles/compactrun.dir/all] Error 2 make: *** [all] Error 2 Is the above to the old compiler or there something else? Regards Tadeusz

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compiling 2.0.2: libboost_mpi missing?
by Mateusz Łącki 29 Nov '11

29 Nov '11

Dear All, I am still trying to compile alps using icc. I have run to a new error: lacki@scud:~/alps/alps-2.0.2-r5790-src-with-boost/alps-2.0.2-r5790-src-with-boost/alps $ make xmlparser [100%] Built target alps Linking CXX executable xmlparser ../../src/alps/libalps.so.2.0.2: undefined reference to `void boost::mpi::broadcast<boost::mpi::packed_iarchive>(boost::mpi::communicator const&, boost::mpi::packed_iarchive&, int)' ../../src/alps/libalps.so.2.0.2: undefined reference to `boost::mpi::exception::exception(char const*, int)' ../../src/alps/libalps.so.2.0.2: undefined reference to `boost::mpi::communicator::barrier() const' (............) ../../src/alps/libalps.so.2.0.2: undefined reference to `boost::mpi::communicator::operator ompi_communicator_t*() const' ../../src/alps/libalps.so.2.0.2: undefined reference to `boost::mpi::environment::~environment()' ../../src/alps/libalps.so.2.0.2: undefined reference to `boost::mpi::communicator::size() const' ../../src/alps/libalps.so.2.0.2: undefined reference to `void boost::mpi::communicator::send<boost::mpi::packed_oarchive>(int, int, boost::mpi::packed_oarchive const&) const' make[3]: *** [test/parser/xmlparser] Error 1 make[2]: *** [test/parser/CMakeFiles/xmlparser.dir/all] Error 2 make[1]: *** [test/parser/CMakeFiles/xmlparser.dir/rule] Error 2 while trying to do "make". The exact make subcommand it corresponds to is "make xmlparser" I enclose my config files. here is a quotation from: alps/config/FindBoostForALPS.cmake # We do not require Boost.MPI, therefore check whether Boost.MPI exists # before actual find_package for Boost. # - Ubuntu 10.10 does not have Boost.MPI package. find_package(Boost 1.43.0 COMPONENTS mpi) if (Boost_FOUND) it seem contradictory with previous message. Also when i try to set boost_mpi directory to /usr/lib64/openmpi/lib where there is libboost_mpi.so.1.46.0 pressing "c" for doing "configure" ereases the path that i have just put in - why is that ? The same linking error appears if I set the path to boost_root_dir correctly - in that case manual specification of location of binary libboost_mpi is no longer an option Regards, Mateusz

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Suggestions on ALPS Simulations
by Suddhasattwa Ghosh 26 Nov '11

26 Nov '11

Dear Sir, We would like to address the following problems using the ALPS package. * * *May I kindly request if you could inform us if these problems could be done using this package? * * * Problem 1 I consider a bcc phase with 3.64 A as lattice parameter. We assume A, B or C (could be Ni,Ti and Nb) *can either occupy* (0,0,0) position. I also assume X(A)=0.40 X(B)=0.40 X(C)=0.20 as composition variables Now, I consider a 40 atom cell which can mimic the most random alloy with this composition. Can I use your code to get the most random alloy for A, B and C. That is to say, getting the structure of this alloy with a 40 atom cell satisfying the compositions using MC simulations at T=298.15 K Can we add any number of elements if we are to construct a disordered alloy of say, 5 elements? Can it be done? Problem 2 I consider a rhombohedral phase with 15-16 A approx. as lattice parameters. I have *five* different inequivalent positions which can *either be occupied * by A or B (say Ni and Fe) I assume composition variables as X(A)=0.60 X(B)=0.40 Can in this case a 40 atom cell be used to generate the most random structure using MC simulations at T=298.15 K Could you please suggest on these issues Sir and inform if ALPS could be used for these cases. With regards Suddhasattwa Ghosh

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Re: [ALPS-users] Comp-phys-alps-users Digest, Vol 68, Issue 9
by Tadeusz Wasiutyński 25 Nov '11

25 Nov '11

Dear Mathias, thank you very much for the hint. Indeed when 64 bit is off, make goes smoothly and make test passed all but 97,98 and 99. I was misled by the package lapack-3.2.1-4.el6(x86_64) which went to /usr/lib64/. By the way my system is Scientific Linux 6.1. Best regards Tadeusz 2011/11/25 <comp-phys-alps-users-request(a)lists.phys.ethz.ch> > Send Comp-phys-alps-users mailing list submissions to > comp-phys-alps-users(a)lists.phys.ethz.ch > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.phys.ethz.ch/listinfo/comp-phys-alps-users > or, via email, send a message with subject or body 'help' to > comp-phys-alps-users-request(a)lists.phys.ethz.ch > > You can reach the person managing the list at > comp-phys-alps-users-owner(a)lists.phys.ethz.ch > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Comp-phys-alps-users digest..." > > > Today's Topics: > > 1. alps-2.0.2 compile error (Tadeusz Wasiuty?ski) > 2. Re: alps-2.0.2 compile error (Mateusz ??cki) > 3. Re: alps-2.0.2 compile error (Matthias Troyer) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 25 Nov 2011 10:07:52 +0100 > From: Tadeusz Wasiuty?ski <tadeusz.wasiutynski(a)ifj.edu.pl> > To: comp-phys-alps-users(a)lists.phys.ethz.ch > Subject: [ALPS-users] alps-2.0.2 compile error > Message-ID: > <CAKNmYXinqnEPFuFv0X32Z=rrvwhU556W1aaOiJwEeAgiNgaoKQ(a)mail.gmail.com > > > Content-Type: text/plain; charset="iso-8859-1" > > Dears, > I had compiled successfully 2.0.1 version and made running with cmake as > follows: > > /home/wasiutyn/opt/bin/cmake -D BLAS_LIBRARY=/usr/lib64/libblas.so.3.2.1 > -D LAPACK_LIBRARY=/usr/lib64/liblapack.so.3.2.1 -D > LPSolve_LIBRARIES=/usr/lib64/liblpsolve55.so -D > LPSolve_INCLUDE_DIR=/usr/include/ -D CMAKE_INSTALL_PREFIX=$HOME/ALPS -D > LAPACK_64_BIT=ON -D HDF5_LIBRARIES=/home/wasiutyn/opt/lib/libhdf5.so.6 -D > HDF5_INCLUDE_DIR=/home/wasiutyn/opt/include/ > ~/alps-2.0.1-r5565-src-with-boost/alps/ > > However with about the same cmake I got: > > -- CMAKE_GENERATOR: Unix Makefiles > -- CMAKE_CL_64: > -- CMAKE_SIZEOF_VOID_P: > -- CMAKE_GENERATOR: Unix Makefiles > -- CMAKE_CL_64: > -- Build type: Release > -- Python interpreter /usr/bin/python > -- Python interpreter ok : version 2.6.6 > -- PYTHON_INCLUDE_DIRS = /usr/include/python2.6 > -- PYTHON_NUMPY_INCLUDE_DIR = > /usr/lib64/python2.6/site-packages/numpy/core/include > -- PYTHON_SITE_PKG = /usr/lib/python2.6/site-packages > -- PYTHON_LIBRARY = /usr/lib64/python2.6/config/libpython2.6.so > -- PYTHON_EXTRA_LIBS =-lpthread -ldl -lutil > -- PYTHON_LINK_FOR_SHARED = -Xlinker -export-dynamic > -- ALPS version: 2.0.2 > -- Looking for Boost Source > -- Found Boost Source: /home/wasiutyn/alps-2.0.2-r5790-src-with-boost/boost > -- Boost Version: 1_47_0 > -- Could NOT find MPI (missing: MPI_LIBRARY MPI_INCLUDE_PATH) > -- MPI compiler was MPI_COMPILER-NOTFOUND > -- Could NOT find SZIP (missing: SZIP_LIBRARIES SZIP_INCLUDE_DIRS) > -- HDF5 version found is 1.8.6 in /home/wasiutyn/opt/include/ > -- Python interpreter /usr/bin/python > -- Python interpreter ok : version 2.6.6 > -- PYTHON_INCLUDE_DIRS = /usr/include/python2.6 > -- PYTHON_NUMPY_INCLUDE_DIR = > /usr/lib64/python2.6/site-packages/numpy/core/include > -- PYTHON_SITE_PKG = /usr/lib/python2.6/site-packages > -- PYTHON_LIBRARY = /usr/lib64/python2.6/config/libpython2.6.so > -- PYTHON_EXTRA_LIBS =-lpthread -ldl -lutil > -- PYTHON_LINK_FOR_SHARED = -Xlinker -export-dynamic > -- Numpy include in /usr/lib64/python2.6/site-packages/numpy/core/include > -- ALPS XML dir is /home/wasiutyn/ALPS2/lib/xml > -- Adding Boost dir: /home/wasiutyn/alps-2.0.2-r5790-src-with-boost/boost > -- HDF5 version found is 1.8.6 in /home/wasiutyn/opt/include/ > -- HDF5 version found is 1.8.6 in /home/wasiutyn/opt/include/ > -- tebd will not be built > -- Configuring done > -- Generating done > -- Build files have been written to: > /home/wasiutyn/alps-2.0.2-r5790-src-with-boost/alps > > during make I receive: > > make[2]: *** > [example/ietl/CMakeFiles/jacobidavidson2.dir/jacobidavidson2.cpp.o] Error 1 > make[1]: *** [example/ietl/CMakeFiles/jacobidavidson2.dir/all] Error 2 > make: *** [all] Error 2 > > The only differece I see in cmake output is Boost Version: now 1_47_0 was > before 1_46_1 > > The same error was already reported earlier by Mateusz Lacki. What is the > solution? > Regards > Tadeusz >

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alps-2.0.2 compile error
by Tadeusz Wasiutyński 25 Nov '11

25 Nov '11

Dears, I had compiled successfully 2.0.1 version and made running with cmake as follows: /home/wasiutyn/opt/bin/cmake -D BLAS_LIBRARY=/usr/lib64/libblas.so.3.2.1 -D LAPACK_LIBRARY=/usr/lib64/liblapack.so.3.2.1 -D LPSolve_LIBRARIES=/usr/lib64/liblpsolve55.so -D LPSolve_INCLUDE_DIR=/usr/include/ -D CMAKE_INSTALL_PREFIX=$HOME/ALPS -D LAPACK_64_BIT=ON -D HDF5_LIBRARIES=/home/wasiutyn/opt/lib/libhdf5.so.6 -D HDF5_INCLUDE_DIR=/home/wasiutyn/opt/include/ ~/alps-2.0.1-r5565-src-with-boost/alps/ However with about the same cmake I got: -- CMAKE_GENERATOR: Unix Makefiles -- CMAKE_CL_64: -- CMAKE_SIZEOF_VOID_P: -- CMAKE_GENERATOR: Unix Makefiles -- CMAKE_CL_64: -- Build type: Release -- Python interpreter /usr/bin/python -- Python interpreter ok : version 2.6.6 -- PYTHON_INCLUDE_DIRS = /usr/include/python2.6 -- PYTHON_NUMPY_INCLUDE_DIR = /usr/lib64/python2.6/site-packages/numpy/core/include -- PYTHON_SITE_PKG = /usr/lib/python2.6/site-packages -- PYTHON_LIBRARY = /usr/lib64/python2.6/config/libpython2.6.so -- PYTHON_EXTRA_LIBS =-lpthread -ldl -lutil -- PYTHON_LINK_FOR_SHARED = -Xlinker -export-dynamic -- ALPS version: 2.0.2 -- Looking for Boost Source -- Found Boost Source: /home/wasiutyn/alps-2.0.2-r5790-src-with-boost/boost -- Boost Version: 1_47_0 -- Could NOT find MPI (missing: MPI_LIBRARY MPI_INCLUDE_PATH) -- MPI compiler was MPI_COMPILER-NOTFOUND -- Could NOT find SZIP (missing: SZIP_LIBRARIES SZIP_INCLUDE_DIRS) -- HDF5 version found is 1.8.6 in /home/wasiutyn/opt/include/ -- Python interpreter /usr/bin/python -- Python interpreter ok : version 2.6.6 -- PYTHON_INCLUDE_DIRS = /usr/include/python2.6 -- PYTHON_NUMPY_INCLUDE_DIR = /usr/lib64/python2.6/site-packages/numpy/core/include -- PYTHON_SITE_PKG = /usr/lib/python2.6/site-packages -- PYTHON_LIBRARY = /usr/lib64/python2.6/config/libpython2.6.so -- PYTHON_EXTRA_LIBS =-lpthread -ldl -lutil -- PYTHON_LINK_FOR_SHARED = -Xlinker -export-dynamic -- Numpy include in /usr/lib64/python2.6/site-packages/numpy/core/include -- ALPS XML dir is /home/wasiutyn/ALPS2/lib/xml -- Adding Boost dir: /home/wasiutyn/alps-2.0.2-r5790-src-with-boost/boost -- HDF5 version found is 1.8.6 in /home/wasiutyn/opt/include/ -- HDF5 version found is 1.8.6 in /home/wasiutyn/opt/include/ -- tebd will not be built -- Configuring done -- Generating done -- Build files have been written to: /home/wasiutyn/alps-2.0.2-r5790-src-with-boost/alps during make I receive: make[2]: *** [example/ietl/CMakeFiles/jacobidavidson2.dir/jacobidavidson2.cpp.o] Error 1 make[1]: *** [example/ietl/CMakeFiles/jacobidavidson2.dir/all] Error 2 make: *** [all] Error 2 The only differece I see in cmake output is Boost Version: now 1_47_0 was before 1_46_1 The same error was already reported earlier by Mateusz Lacki. What is the solution? Regards Tadeusz

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Structure factor
by "Michał Maik" 22 Nov '11

22 Nov '11

Hello, I had another question regarding the structure factor of the 2D triangular lattice. I am currently using the SSE and worms code (interchangably) in order to study spins or hardcore bosons on a triangular lattice in finite temperature. Using these codes I am able to get the spin or density structure factor but only for the Q=(0, 0) case. I am interested in the Q=(4*Pi/3, 0) case in order to search for supersolid phases. Is there a way to specify the different wave vectors in these programs in order to get the correct structure factors? Thank you for the help. Best Regards Michal

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cmake error
by Mateusz Łącki 22 Nov '11

22 Nov '11

Dear All I wish to report the following error that occured while trying to reconfigure the cmake scripts: CMake Error at config/FindLapack.cmake:43 (STRING): string sub-command REGEX, mode REPLACE needs at least 6 arguments total to command. Call Stack (most recent call first): CMakeLists.txt:315 (find_package) this shows in ccmake after pressing "c". Therefore option to "generate" does not show. and this:-- MPI compiler was /opt/openmpi-1.5-intel/bin/mpic++ -- Using intel/mkl library: /opt/intel/composerxe-2011.1.107/mkl CMake Error at config/FindLapack.cmake:43 (STRING): string sub-command REGEX, mode REPLACE needs at least 6 arguments total to command. Call Stack (most recent call first): CMakeLists.txt:315 (find_package) during make Regards, Mateusz Lacki

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Re: [ALPS-users] BONDOPERATOR measurement question
by Sebastian Huber 22 Nov '11

22 Nov '11

Attached the input files. If I remeber correctly, with alps 2.0.0 I did not encounter this problem. Sebastian -- Sebastian Huber Department of Condensed Matter Physics The Weizmann Institute of Science 76100 Rehovot Web: http://www.weizmann.ac.il/~huber Tel: +972 8 934 4258 On 22.11.2011, at 09:36, Matthias Troyer wrote: > Can you please send the full input files as attachment and I will take a look? > > Matthias > > On Nov 22, 2011, at 12:17 AM, Sebastian Huber wrote: > >> Didn't help. I played a bit with operator names. But the fact that MEASURE_LOCAL does perform something made me believe that it is not the cure. >> >> Thanks for the quick answer, Sebastian >> -- >> Sebastian Huber >> Department of Condensed Matter Physics >> The Weizmann Institute of Science >> 76100 Rehovot >> >> Web: http://www.weizmann.ac.il/~huber >> Tel: +972 8 934 4258 >> >> On 22.11.2011, at 01:11, Matthias Troyer wrote: >> >>> Try not to use a minus (-) in the operator name, but instead an underscore or similar >>> >>> >>> On 22 Nov 2011, at 00:09, Sebastian Huber wrote: >>> >>>> Dear all, >>>> >>>> I have an inhomogeneous lattice problem and I try to measure a "local" bondoperator, e.g., the current over one bond only. I get the following error from the sparsediag application >>>> >>>> Did not parse to end of string '(one-bond)/4(i)' >>>> >>>> when I try to do a "MEASURE_AVERAGE". I get no error if I use "MEASURE_LOCAL". I am a bit puzzled that "MEASURE_LOCAL" does something all together as my operator contains more than one site, which is in violation to a condition on local measurements on the alps webpage. I paste a minimal (silly) set of configuration files which produces this error below. Help would be greatly appreciated. >>>> >>>> Sebastian >>>> >>>> lanczosconf: >>>> >>>> MODEL="simple"; >>>> LATTICE="2x2" >>>> LATTICE_LIBRARY="graph.xml" >>>> MODEL_LIBRARY="model.xml" >>>> COMPLEX=true; >>>> t=-1; >>>> Nup_total=1; >>>> Ndown_total=1; >>>> CONSERVED_QUANTUMNUMBERS="N,Sz"; >>>> NUMBER_EIGENVALUES=2; >>>> TRANSLATION_SYMMETRY=false; >>>> MEASURE_AVERAGE[one-bond]=one-bond; >>>> {U=1;} >>>> >>>> >>>> graph.xml: >>>> >>>> <LATTICES> >>>> >>>> <GRAPH name="2x2" dimension="2" vertices="4" edges="9"> >>>> <VERTEX id="1" type="0"><COORDINATE>0 0</COORDINATE></VERTEX> >>>> <VERTEX id="2" type="0"><COORDINATE>1 0</COORDINATE></VERTEX> >>>> <VERTEX id="3" type="0"><COORDINATE>0 1</COORDINATE></VERTEX> >>>> <VERTEX id="4" type="0"><COORDINATE>1 1</COORDINATE></VERTEX> >>>> <EDGE source="1" target="2" id="1" type="1" vector="1 0"/> >>>> <EDGE source="2" target="1" id="2" type="2" vector="1 0"/> >>>> <EDGE source="3" target="4" id="3" type="3" vector="1 0"/> >>>> <EDGE source="4" target="3" id="4" type="4" vector="1 0"/> >>>> <EDGE source="1" target="3" id="5" type="5" vector="0 1"/> >>>> <EDGE source="2" target="4" id="6" type="6" vector="0 1"/> >>>> <EDGE source="3" target="1" id="7" type="7" vector="0 1"/> >>>> <EDGE source="4" target="2" id="8" type="8" vector="0 1"/> >>>> <EDGE source="1" target="4" id="9" type="9" vector="1 1"/> >>>> </GRAPH> >>>> >>>> </LATTICES> >>>> >>>> >>>> model.xml >>>> >>>> <MODELS> >>>> <SITEBASIS name="fermion"> >>>> <QUANTUMNUMBER name="Nup" min="0" max="1" type="fermionic"/> >>>> <QUANTUMNUMBER name="Ndown" min="0" max="1" type="fermionic"/> >>>> <OPERATOR name="Splus" matrixelement="1/2"> >>>> <CHANGE quantumnumber="Nup" change="1"/> >>>> <CHANGE quantumnumber="Ndown" change="-1"/> >>>> </OPERATOR> >>>> <OPERATOR name="Sminus" matrixelement="1/2"> >>>> <CHANGE quantumnumber="Nup" change="-1"/> >>>> <CHANGE quantumnumber="Ndown" change="+1"/> >>>> </OPERATOR> >>>> <OPERATOR name="Sz" matrixelement="(Nup-Ndown)/2"/> >>>> <OPERATOR name="Nup" matrixelement="Nup"/> >>>> <OPERATOR name="Ndown" matrixelement="Ndown"/> >>>> <OPERATOR name="c_down" matrixelement="1"> >>>> <CHANGE quantumnumber="Ndown" change="-1"/> >>>> </OPERATOR> >>>> <OPERATOR name="cdag_down" matrixelement="1"> >>>> <CHANGE quantumnumber="Ndown" change="1"/> >>>> </OPERATOR> >>>> <OPERATOR name="c_up" matrixelement="1"> >>>> <CHANGE quantumnumber="Nup" change="-1"/> >>>> </OPERATOR> >>>> <OPERATOR name="cdag_up" matrixelement="1"> >>>> <CHANGE quantumnumber="Nup" change="1"/> >>>> </OPERATOR> >>>> <OPERATOR name="n" matrixelement="Nup+Ndown"/> >>>> <OPERATOR name="n_up" matrixelement="Nup"/> >>>> <OPERATOR name="n_down" matrixelement="Ndown"/> >>>> </SITEBASIS> >>>> >>>> <BASIS name="fermion"> >>>> <SITEBASIS ref="fermion"/> >>>> <CONSTRAINT quantumnumber="Nup" value="Nup_total"/> >>>> <CONSTRAINT quantumnumber="Ndown" value="Ndown_total"/> >>>> </BASIS> >>>> >>>> <BONDOPERATOR name="one-bond" source="1" target="2"> >>>> I*(cdag_up(1)*c_up(2)-cdag_up(2)*c_up(1)) >>>> </BONDOPERATOR> >>>> >>>> <HAMILTONIAN name="simple"> >>>> <PARAMETER name="U" default="1"/> >>>> <BASIS ref="fermion"/> >>>> <SITETERM site="i"> >>>> U*n_up(i)*n_down(i) >>>> </SITETERM> >>>> </HAMILTONIAN> >>>> >>>> </MODELS> >>>> >>>> -- >>>> Sebastian Huber >>>> Department of Condensed Matter Physics >>>> The Weizmann Institute of Science >>>> 76100 Rehovot >>>> >>>> Web: http://www.weizmann.ac.il/~huber >>>> Tel: +972 8 934 4258 >>>> >>> >> >

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