December 2012 - Comp-phys-alps-users

Inconsistent comment in generate_spline_matrix in the DMFT folder
by Kuangshing Chen 22 Jul '15

22 Jul '15

Hi, The function generate_spline_matrix in fouriertransform.C in the dmft folder shows the comments as follows: // A is the matrix whose inverse defines spline_matrix // // 6 6 // 1 4 1 // 1 4 1 // A = ... // // 1 4 1 // -2 0 0 2 However, the following codes, dense_matrix A = 4*dt/6.*boost::numeric::ublas::identity_matrix<double>(Np1); for (int i=1; i<Np1-1; i++) { A(i,i-1) = dt/6.; A(i,i+1) = dt/6.; } A(0,0) = 1.; A(0, Np1-1) = 1.; A(Np1-1, 0) = -2.*dt/6.; A(Np1-1, 1) = -1.*dt/6.; A(Np1-1, Np1-2) = 1*dt/6.; A(Np1-1, Np1-1) = 2*dt/6.; the red lines will make the matrix looks like // 6 6 // 1 4 1 // 1 4 1 // A = ... // // 1 4 1 // -2 *-1* *1* 2 Is the comment correct or the code correct? Any reference for this algorithm? Thank you, Kuang-Shing Chen

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How to use the hybridization expansion impurity solver libraries?
by backes＠th.physik.uni-frankfurt.de 13 Feb '13

13 Feb '13

Dear all, right now I'm working on a LDA+DMFT code and want to use the Hybridization Impurity Solver from the ALPS package. I have two questions regarding the implementation of the Impurity solver and would be very glad if you could provide me with some guidiance: My first question is, what is the best way to implement the impurity solver in a C++ code? What I've done so far is the following: I'm using the newest ALPS code version 2.1.1-r6176. By modifying the CMakeLists.txt files I compiled the code from the hybridization2 folder into a static library libhybridization_impl2.a which I planned to use. I included the impurity.h header file in my code and added the following Include- and Library-paths into my makefile: -L$(ALPS_DIR)/alps/src/boost -lboost \ -L$(ALPS_DIR)/alps/src/alps -lalps \ -L$(ALPS_DIR)/alps/applications/dmft/qmc -lhybridization_impl2 \ -L$(HOME)/local/lib/hdf5 -lsz \ -L$(HOME)/GotoBLAS2/current -lgoto2 \ -L/usr/lib/openmpi/lib -lmpi -lmpi_cxx \ -L/opt/intel/Compiler/11.1/046/lib/intel64 -limf -lirc -lifcore -lsvml -I$(ALPS_DIR)/alps/src \ -I$(ALPS_DIR)/alps/src/alps/ngs/lib \ -I$(ALPS_DIR)/alps/applications/dmft/qmc \ -I$(ALPS_DIR)/alps/applications/dmft/qmc/hybridization2 \ -I/usr/lib/openmpi/include As a reference I used the main.C file in the hybridization2 folder. Therefore, calling the impurity solver looks like this: int main(int argc, char *argv[]) { ... #ifdef USE_MPI boost::mpi::environment env(argc, argv); boost::mpi::communicator world; #endif ... //Do all initalization, generate intial Weiss-Field/Bath-GF //Enter DMFT loop while(!converged) { //Save Weiss-Field/Bath-GF into HDF5 file for the solver ... alps::mcoptions options(argc, argv); if (options.valid) { alps::parameters_type<hybridization>::type parms(alps::hdf5::archive(options.input_file, "r")); alps::parallel<hybridization> s(parms, world); if(options.time_limit!=0) throw std::invalid_argument("time limit is passed in the parameter file!"); if(!parms.defined("MAX_TIME")) throw std::runtime_error("parameter MAX_TIME is not defined. How long do you want to run the code for? (in seconds)"); s.run(boost::bind(&stop_callback, boost::posix_time::second_clock::local_time() + boost::posix_time::seconds((int)parms["MAX_TIME"]))); if (world.rank()==0) { alps::results_type<hybridization>::type results = collect_results(s); save_results(results, parms, options.output_file, "/simulation/results"); } ... //Read the results from the output file and convert //the Impurity GF from Legendre representation to //Matsubara representation. } //Do remaining DMFT steps: //Get Selfenergy //Hilbert-Transformation //Get new bath GF //check convergence } //end of DMFT loop } Everything seems to work quite well but I would also like to use the functions that print information about the percentage of work done and I want to feed and read my data directly in/to the impurity solver without writing them into a file. So the way I currently do it is far away from optimal. Can you give me a general advice on how you intended the impurity solver to be used in a C++ code? Another problem that I have, but want to adress after I resolved my first question, is that the GF from the Impurity Solver is not decaying like 1/w_n but with some factor ~ 1/1.5w_n. I'm using the Legendre representation of the GF and transform it back for further use in the DMFT cycle. Do you know a possible reason for this? Is this simply caused by too few Sweeps or Legendre coefficients? I'd greatly appreciate your help. Sincerely, Steffen Backes

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questions about wavefucntion
by 黄口口 01 Jan '13

01 Jan '13

Dear alps users: Now I am learning ALPS. It's useful for me. But I have question: How to get the wave function or some calculation about it, for example, 1.the participation ratio(=1 / \sum_i ｜< i | \psi > |^4 ) 2.calculation of entropy. I search in the mail group, some people face the same difficulty, but I cannot find the answer, can any of you provide me the solution? Thank you! Best wishes to you! xin 2012.11.08

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question about sparsediag
by 陈巧妮 01 Jan '13

01 Jan '13

Hi, everyone When I use sparsediag to diagnalize the Hamiltonian of Hubbard model, the paprameter is : CONSERVED_QUANTUMNUMBERS="Nup,Ndown" Nup_total=6 Ndown_total=6 the system size is L=12, no translation symmetry here, the process will take 100s, which is much slower than our own Davison code(It only take 20s). if I add the measurements MEASURE_ENERGY="True" MEASURE_LOCAL[density]=n MEASURE_LOCAL[double occupancy]=U*double_occupancy MEASURE_CORRELATIONS[density matrix_up]="cdag_up:c_up" MEASURE_CORRELATIONS[density matrix_down]="cdag_down:c_down" the process will take 900s. Does anyone know how to speed up this calculation? Or at least avoid the waste time on the measurements -- Qiaoni Chen Department of Chemistry, Princeton University Princeton, NJ, 08544 Tel +1-609-865-0817

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Green's function measurement in the loop and directed loop codes
by Francisco Cordobés 01 Jan '13

01 Jan '13

Hello, I was wondering what is the definition that that the loop and directed loop code return when the options: 'MEASURE[Correlations]' : True, 'MEASURE[Structure Factor]' : True, 'MEASURE[Green Function]' : True, Because I haven't been able to find them and I would like to know what they are and more importantly what prefactors it has or it hasn't. Thank you very much, Francisco Cordobes

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4 point correlations
by "Michał Maik" 31 Dec '12

31 Dec '12

Hi, I was wondering if there was a way to calculate any 4 point correlation functions. I am interested in calculating: <a_dag(i) a_dag(i) a(j) a(j)> I would like to look at pair superfliudity and these correlation functions would be very useful. As a side question, is there a way to use the winding numbers from the worms code output to study this effect? Thank you. Best Michal Maik

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Fwd: string order parameter in ALPS
by Synge Todo 31 Dec '12

31 Dec '12

Dear ALPS Developers, Can anyone tell him how to measure the string order parameter in the ALPS exact diagonalization code, or in the ALPS DMRG code? Best, Synge Begin forwarded message: > 差出人（再送）: wistaria(a)ap.t.u-tokyo.ac.jp > 差出人: hamid mosadegh <hamid.mosadegh(a)gmail.com> > 件名: Re: string order parameter in ALPS > 日時: 2012年11月27日 14:30:20 JST > 宛先: Synge Todo <wistaria(a)comp-phys.org> > > Dear Professor Todo > > Do you know any codes or libraries to evaluate string order for fermion Hubbard. > If there is any code, I think i must write it myself. > Is it possible to access to eigenvectors calculated using ALPS. > If I have these eigenvectors, i can evaluate string order. > > Thanks for attentions and good answers.

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question about ALPS
by hamid 31 Dec '12

31 Dec '12

Dear ALPS user is it possible to define a distance dependent terms to Hamiltonians ,like this term, V/|i-j| I try to define this term but the program can not evaluate i & j. thanks in advance

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pyalps functions description
by Deepak Iyer 30 Dec '12

30 Dec '12

Hi New user here. I've been looking for some docs where there is a complete list of all the pyalps functions with descriptions. Also, is there some place I can find a list of all the hardcoded measurements, etc.? Thanks! Deepak

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Import Error for ALPS on Windows 7
by Jay Deep Sau 29 Dec '12

29 Dec '12

Hi, I am trying to install ALPS on 64 bit Windows 7. I followed the following steps: (1) I installed vistrails from the binary executable. (2) I then downloaded and installed ALPS (both from the main binary package and also the nightly snapshot) and also the ALPS vistrails binary package. (3) I set the paths manually to add C:\Program Files\Vistrails\vistrails\Python27_64\;C:\Program Files\Vistrails\vistrails\Python27_64\lib\;C:\Program Files\ALPS\bin\; so that vispython and python can be run from the command prompt. (4) I copied the tutorial directory to my Desktop. (5) I then entered the tutorial directory and executed test_py.py using python. The resulting pytest.log was as follows: >>>>>>>>>>>>>>>>> dmft-02-hybridization\tutorial2a.py: Traceback (most recent call last): File "tutorial2a.py", line 27, in <module> import pyalps from ngs import * File "C:\Program Files\VisTrails\vistrails\Python27_64\lib\site-packages\pyalps\ngs.py", line 61, in <module> from pyngsobservable_c import createRealObservable #remove this with new ALEA! ImportError: cannot import name createRealObservable >>>>>>>>>>>>>>>>>>>>>>>>>>>> I got a similar error when I typed import pyalps in vispython. Any suggestions on what I did wrong would be great. thanks, Jay Deep Sau.

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