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

memory usage in DMRG
by Mateusz Łącki 11 Sep '14

11 Sep '14

Dear All, I have been running the following input: <pasted at the bottom> I have observed that for Bose-Hubbard model on chain of length L=256, unit filled, under open boundary conditions the DMRG code uses over 32G memory (this is the hardware limit, it clearly wants more, for L=128 it was around 20G). is that normal? I would estimate that an MPS state of 256 sites, with bond dimension 60, local Hilbert space 7 should be much smaller (even if we allow for a small constant factor for temporary data) Kind Regards, Mateusz Łącki LATTICE="open chain lattice" MODEL="boson Hubbard" SWEEPS=8 Nmax=6 NUMBER_EIGENVALUES=1 L=256 CONSERVED_QUANTUMNUMBERS="N" N_total=256 VERBOSE=0 t=0.25 U=1 mu=0 {MAXSTATES=60}

2 2

additional update
by tesfaye mamuye 10 Sep '14

10 Sep '14

Dear ALPS Developers/users I am using alps CT-QMC(Hybridization expansion) as impurity solver. But the total acceptance rate is getting low and low, and I'm wondering if it may affect the final result. In order to overcome this, I'm thinking to use additional update: 'shift of the segment end point' which is used to enhance the sampling efficiency (to increase the acceptance ratio and reduce auto-correlation times) which do not change the expansion order. However, I didn't get in the documentation on how to implement this additional update as control parameter 'SPINFLIP'={0.1} : specify to whether to perform spin flip update. Is it possible to use for shift of the segment end point update 'N_SHIFT'=1 ? I need help on how to implement this additional update. here is the sample |------ Simulation details (master only) after 2665880 sweeps ------| Total acceptance rate = 22.92% Individual acceptance rate for update change zero state = 0.00% (proposal rate = 10.00%) insert segment = 6.37% (proposal rate = 25.00%) remove segment = 6.37% (proposal rate = 25.00%) insert anti-segment = 5.09% (proposal rate = 20.00%) remove anti-segment = 5.09% (proposal rate = 20.00%) swap segment = 0.00% (proposal rate = 0.00%) |-----------------------------------------------------------------| Thank you for your time

2 2

Help with LiveALPS
by Niraj Ghimire 10 Sep '14

10 Sep '14

Dear ALPS users, I have been running LiveALPS from my USB flash drive and I can't get access to the internet. I could not find any information anywhere on how to resolve this issue. Would you be able to help me out ? ~Niraj

3 2

(no subject)
by hamid mosadegh 07 Sep '14

07 Sep '14

Dear All What is the momentum of , E_1(N_{\uparrow},(N_{\downarrow} ,L), the lowest-excitation energy in the Hubbard model in the S=0 sector. I means, I want to evaluate the velocity of charge excitation from E_1(N_{\uparrow},(N_{\downarrow} ,L)- E_0(N_{\uparrow},(N_{\downarrow} ,L) where E_1(N_{\uparrow},(N_{\downarrow} ,L) is the lowest-excitation energy with momentum k=2\pi/L and total spin S=0. If i run MODEL="fermion Hubbard" CONSERVED_QUANTUMNUMBERS="Nup,Ndown" Ndown_total=10;Nup_total=10 NUMBER_EIGENVALUES=2 what is the momentum of first excitation. is it possible to determine or change it? thanks H. Mosadeq Shahr-e-Kord University (SKU), Shahr-e-Kord , Iran

2 6

the parity sector in DMRG
by hamid mosadegh 03 Sep '14

03 Sep '14

Dear all Is it possible to do the DMRG or ED calculations of fermion Hubbard model in the odd(even) parity sector using ALPS? I need to determine the minimum energies for eigenstates in the even and odd parity sectors. Thanks -- H. Mosadeq Shahr-e-Kord University (SKU), Shahr-e-Kord , Iran

3 3

parallel calculation on Windows
by orchidwood 01 Sep '14

01 Sep '14

Dear all, Can the ALPS on 64-bit Windows 7 do parallel calculation with Vistrail system? If it can do this, how?Thanks,Mu Lan

2 1

Re: [ALPS-users] Comp-phys-alps-users Digest, Vol 101, Issue 14
by bonanjiang＠gmail.com 26 Aug '14

26 Aug '14

Hi, Matthias, Since you said sparsediag was the code to use, then how to set the number of eignstates to calculate in the parameter file or command line? I can not find the answer in the turtorials. Bo-Nan bonanjiang(a)gmail.com From: comp-phys-alps-users-request Date: 2014-08-26 18:00 To: comp-phys-alps-users Subject: Comp-phys-alps-users Digest, Vol 101, Issue 14 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. Help with LiveALPS (Niraj Ghimire) 2. a question about fulldiag (bonanjiang(a)gmail.com) 3. Re: a question about fulldiag (Matthias Troyer) ---------------------------------------------------------------------- Message: 1 Date: Mon, 25 Aug 2014 12:08:57 -0400 From: Niraj Ghimire <niraj.ghimire(a)gmail.com> To: "comp-phys-alps-users(a)lists.comp-phys.org" <comp-phys-alps-users(a)lists.comp-phys.org> Subject: [ALPS-users] Help with LiveALPS Message-ID: <CACMdJOXGtHsttzbF-+1LLxL3OmvdnntrTvcQjiJ9fsCXUGk1jQ(a)mail.gmail.com> Content-Type: text/plain; charset="utf-8" Dear ALPS users, I have been running LiveALPS from my USB flash drive and I can't get access to the internet. I could not find any information anywhere on how to resolve this issue. Would you be able to help me out ? ~Niraj -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://lists.phys.ethz.ch/pipermail/comp-phys-alps-users/attachments/20140…> ------------------------------ Message: 2 Date: Tue, 26 Aug 2014 14:41:48 +0800 From: "bonanjiang(a)gmail.com" <bonanjiang(a)gmail.com> To: comp-phys-alps-users <comp-phys-alps-users(a)lists.phys.ethz.ch> Subject: [ALPS-users] a question about fulldiag Message-ID: <201408261441449660406(a)gmail.com> Content-Type: text/plain; charset="us-ascii" Hi, all I currently tend to calculate the energy of the lowest 4 states of a fermion system with fulldiag of ALPS. However, since the system has 12 eigenstates in total and fulldiag gives all of them, the time it takes is a little bit long. So, my question is: is there any way to limit the number of eigenstates that fulldiag calculates? for example, the lowest 4 states. Bo-Nan bonanjiang(a)gmail.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://lists.phys.ethz.ch/pipermail/comp-phys-alps-users/attachments/20140…> ------------------------------ Message: 3 Date: Tue, 26 Aug 2014 08:56:54 +0200 From: Matthias Troyer <troyer(a)phys.ethz.ch> To: "comp-phys-alps-users(a)lists.phys.ethz.ch" <comp-phys-alps-users(a)lists.phys.ethz.ch> Subject: Re: [ALPS-users] a question about fulldiag Message-ID: <362E955B-595C-4AE6-A412-27EA6F8EEA63(a)phys.ethz.ch> Content-Type: text/plain; charset="us-ascii" sparsediag is the code to use in this case > On Aug 26, 2014, at 8:41, "bonanjiang(a)gmail.com" <bonanjiang(a)gmail.com> wrote: > > Hi, all > I currently tend to calculate the energy of the lowest 4 states of a fermion system with fulldiag of ALPS. However, since the system has 12 eigenstates in total and fulldiag gives all of them, the time it takes is a little bit long. So, my question is: is there any way to limit the number of eigenstates that fulldiag calculates? for example, the lowest 4 states. > > Bo-Nan > bonanjiang(a)gmail.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <https://lists.phys.ethz.ch/pipermail/comp-phys-alps-users/attachments/20140…> End of Comp-phys-alps-users Digest, Vol 101, Issue 14 *****************************************************

2 1

a question about fulldiag
by bonanjiang＠gmail.com 26 Aug '14

26 Aug '14

Hi, all I currently tend to calculate the energy of the lowest 4 states of a fermion system with fulldiag of ALPS. However, since the system has 12 eigenstates in total and fulldiag gives all of them, the time it takes is a little bit long. So, my question is: is there any way to limit the number of eigenstates that fulldiag calculates? for example, the lowest 4 states. Bo-Nan bonanjiang(a)gmail.com

2 1

Help with LiveALPS
by Niraj Ghimire 20 Aug '14

20 Aug '14

Dear alps users, I am running LiveALPS on my computer and I cannot get access to the internet. I could not find any information anywhere on it. Could you please let me know how I can fix this issue ? ~Niraj

1 0

Computing correlations with sparsediag
by Eoin Quinn 18 Aug '14

18 Aug '14

Dear ALPS users, I have a question regarding the calculation of correlations with sparsediag. Let me take for an example a one-dimensional ferromagnetic spin chain of length 4. I will not impose ‘Sz’ conservation as the problem I am having arises when ‘Sz’ is not conserved, once I impose it all works well. The following are my input parameters for the calculation: <PARAMETERS> <PARAMETER name="MEASURE_CORRELATIONS[Offdiagonal spin correlations]">Splus:Sminus</PARAMETER> <PARAMETER name="NUMBER_EIGENVALUES">1</PARAMETER> <PARAMETER name="BC">periodic</PARAMETER> <PARAMETER name="local_S">0.5</PARAMETER> <PARAMETER name="J">-1</PARAMETER> <PARAMETER name="L">4</PARAMETER> <PARAMETER name="LATTICE">chain lattice</PARAMETER> <PARAMETER name="SEED">911696590</PARAMETER> <PARAMETER name="W">1</PARAMETER> <PARAMETER name="MODEL">spin</PARAMETER> <PARAMETER name="MODEL_LIBRARY">aux/models.xml</PARAMETER> <PARAMETER name="LATTICE_LIBRARY">aux/lattices.xml</PARAMETER> <PARAMETER name="MEASURE_CORRELATIONS[Diagonal spin correlations]">Sz</PARAMETER> <PARAMETER name="CONSERVED_QUANTUMNUMBERS"></PARAMETER> <PARAMETER name="TOTAL_MOMENTUM">4.712388980384689674</PARAMETER> </PARAMETERS> The output for the ground state is then <EIGENSTATES number="1"> <QUANTUMNUMBER name="TOTAL_MOMENTUM" value="0"/> <EIGENSTATE number="0"> <SCALAR_AVERAGE name="Energy"><MEAN>-1</MEAN></SCALAR_AVERAGE> <VECTOR_AVERAGE name="Diagonal spin correlations"> <SCALAR_AVERAGE indexvalue="( 0 ) -- ( 0 )"><MEAN>0.24999999999999997</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0 ) -- ( 1 )"><MEAN>0.0078869096162297037</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0 ) -- ( 2 )"><MEAN>0.0078869096162296551</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0 ) -- ( 3 )"><MEAN>0.0078869096162297071</MEAN></SCALAR_AVERAGE> </VECTOR_AVERAGE> <VECTOR_AVERAGE name="Offdiagonal spin correlations"> <SCALAR_AVERAGE indexvalue="( 0 ) -- ( 0 )"><MEAN>0.55359228338317501</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0 ) -- ( 1 )"><MEAN>0.24211309038377027</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0 ) -- ( 2 )"><MEAN>0.2421130903837703</MEAN></SCALAR_AVERAGE> <SCALAR_AVERAGE indexvalue="( 0 ) -- ( 3 )"><MEAN>0.24211309038377027</MEAN></SCALAR_AVERAGE> </VECTOR_AVERAGE> </EIGENSTATE> </EIGENSTATES> The problem I am having is that the diagonal and off diagonal components of the ( 0 ) -- ( 0 ) spin correlations do not sum to 3/4 = S(S+1) = \vec{S}.\vec{S}, whereas I would expect them to. Do I understand correctly that the "Diagonal spin correlations" give <S^z(i) S^z(j)> and the "Offdiagonal spin correlations" give <S^x(i) S^x(j) + S^y(i) S^y(j)>? With best regards, Eoin

2 3