Comp-phys-alps-users

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1244 discussions

truncation error in DMRG
by Bo-Nan JIANG 16 Mar '13

16 Mar '13

Hi,all In DMRG, what does the sign of truncation error mean? In today's ALPS DMRG, I have got a negative truncation error, wow! So, I think what does a negative truncation error mean? the same as the positive one? Bo-Nan -- Stay foolish,Stay hungry.

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Re: [ALPS-users] Comp-phys-alps-users Digest, Vol 84, Issue 13
by Bo-Nan JIANG 16 Mar '13

16 Mar '13

First, Thanks a lot, Ryo. And second, I am still waiting the answer of DMRG error of Kondo lattice from Matthias, since I have sent you guys parameter file, lattice file and model file. Best, Bo-Nan 2013/3/15 <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. Kondo lattice DMRG input file (Bo-Nan JIANG) > 2. the right way to define a harmonic trap (Bo-Nan JIANG) > 3. truncation error in DMRG (Bo-Nan JIANG) > 4. Question about simulation output (Prof. Dr. Thomas Pruschke) > 5. Re: the right way to define a harmonic trap (Ryo IGARASHI) > 6. TEBD in ALPS (Bo-Nan JIANG) > 7. Re: TEBD in ALPS (Ryo IGARASHI) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 15 Mar 2013 08:16:25 +0800 > From: Bo-Nan JIANG <bonanjiang(a)gmail.com> > To: "comp-phys-alps-users(a)lists.phys.ethz.ch" > <comp-phys-alps-users(a)lists.phys.ethz.ch> > Subject: [ALPS-users] Kondo lattice DMRG input file > Message-ID: > <CADqUQBPtKTLoVmWX-V7XRvNkgk= > dpYa4TQ-SgB+rJ4__Mb2JZA(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Hi,Matt > This is the input parameter file with your ALPS Kondo lattice model, the > DMRG parameters are chosen so that the calculation can finish in a short > time, thus be easy to be debugged : > > --------------------------------INPUT PARAMETER FILE (FILE NAME > my_parm)----------------------------------------- > > LATTICE_LIBRARY="my_lattices.xml" > LATTICE="chain lattice" > MODEL="Kondo lattice" > mu=0 > t=1 > J=0.2 > {L=32 > SWEEPS=4 > MAXSTATES=40 > NUMBER_EIGENVALUES=2} > > -----------------------------END OF INPUT PARAMETER > FILE--------------------------------- > > > > -----------------------------my_lattices.xml-------------------------------------------------------------- > > <LATTICES> > > <LATTICE name="chain lattice" dimension="1"> > <PARAMETER name="a" default="1"/> > <BASIS><VECTOR>a</VECTOR></BASIS> > <RECIPROCALBASIS><VECTOR>2*pi/a</VECTOR></RECIPROCALBASIS> > </LATTICE> > <UNITCELL name="fermion" dimension="1"> > <VERTEX type="0"/> > <VERTEX type="1"/> > <EDGE type="0"><SOURCE vertex="1" offset="0"/><TARGET vertex="1" > offset="1"/></EDGE> > <EDGE type="1"><SOURCE vertex="1" offset="0"/><TARGET vertex="2" > offset="0"/></EDGE> > </UNITCELL> > <LATTICEGRAPH name = "chain lattice"> > <FINITELATTICE> > <LATTICE ref="chain lattice"/> > <PARAMETER name="L" default="4"/> > <EXTENT size="L"/> > <BOUNDARY type="open"/> > </FINITELATTICE> > <UNITCELL ref="fermion"/> > </LATTICEGRAPH> > > </LATTICES> > > -------------------------END OF > my_lattices.xml---------------------------------------- > > > -------------------------COMMAND LINE > INPUT----------------------------------------- > > parameter2xml my_parm > > dmrg --write-xml my_parm.in.xml > > ------------------------END OF COMMAND LINE > INPUT------------------------------- > > ERROR: site basis for type 2 not found. Hope you guys can find out what is > going on. > > > > > By the way, if I use wild card and my custom fermion code to reprogram > Model="Kondo lattice" in the fashion of your ALPS Model="spin", the DMRG > and ED both works. But the problem is with mu=0 t=1 and J=1, by DMRG, my > custom Kondo Lattice model shows the gap = 0.21, with 10^-10 truncation > error, while K.Ueda in Phys.Rev.B. 46, 3175 FIG.1 shows a energy gap > smaller than 0.2 under the same parameter condition by ED. (BOTH HALF > FILLING) I recheck my custom Kondo lattice model and find no obvious > mistakes. And I do not know why, can you help me here, too? > > --------------------------INPUT FILE OF CUSTOM KONDO LATTICE > MODEL------------------------------ > > LATTICE_LIBRARY="my_lattices.xml" > LATTICE="chain lattice" > MODEL_LIBRARY="my_models.xml" > MODEL="Kondo lattice" > CONSERVED_QUANTUMNUMBERS="N" > N_total=128 > MEASURE_LOCAL[local density]=n > local_max0=2 > local_min0=0 > local_max1=1 > local_min1=1 > mu=0 > t=1 > J=1 > {L=64 > SWEEPS=10 > MAXSTATES=500 > NUMBER_EIGENVALUES=2} > > > ------------------------CUSTOM KONDO LATTICE > MODEL-------------------------- > > <MODELS> > <SITEBASIS name="fermion"> > <PARAMETER name="local_maximum" default="local_max"/> > <PARAMETER name="local_max" default="2"/> > <PARAMETER name="local_minimun" default="local_min"/> > <PARAMETER name="local_min" default="0"/> > <QUANTUMNUMBER name="N" min="local_minimum" max="local_maximum" > type="fermionic"/> > <QUANTUMNUMBER name="Sz" min="-N*(2-N)/2" max="N*(2-N)/2"/> > <QUANTUMNUMBER name="Nup" min="(N+2*Sz)/2" max="(N+2*Sz)/2"/> > <QUANTUMNUMBER name="Ndown" min="(N-2*Sz)/2" max="(N-2*Sz)/2"/> > <OPERATOR name="Splus" matrixelement="1"> > <CHANGE quantumnumber="Nup" change="1"/> > <CHANGE quantumnumber="Ndown" change="-1"/> > <CHANGE quantumnumber="Sz" change="1"/> > </OPERATOR> > <OPERATOR name="Sminus" matrixelement="1"> > <CHANGE quantumnumber="Nup" change="-1"/> > <CHANGE quantumnumber="Ndown" change="+1"/> > <CHANGE quantumnumber="Sz" change="-1"/> > </OPERATOR> > <OPERATOR name="Sz" matrixelement="Sz"/> > <OPERATOR name="c_down" matrixelement="1"> > <CHANGE quantumnumber="Ndown" change="-1"/> > <CHANGE quantumnumber="N" change="-1"/> > <CHANGE quantumnumber="Sz" change="1/2"/> > </OPERATOR> > <OPERATOR name="cdag_down" matrixelement="1"> > <CHANGE quantumnumber="Ndown" change="1"/> > <CHANGE quantumnumber="N" change="1"/> > <CHANGE quantumnumber="Sz" change="-1/2"/> > </OPERATOR> > <OPERATOR name="c_up" matrixelement="1"> > <CHANGE quantumnumber="Nup" change="-1"/> > <CHANGE quantumnumber="N" change="-1"/> > <CHANGE quantumnumber="Sz" change="-1/2"/> > </OPERATOR> > <OPERATOR name="cdag_up" matrixelement="1"> > <CHANGE quantumnumber="Nup" change="1"/> > <CHANGE quantumnumber="N" change="1"/> > <CHANGE quantumnumber="Sz" change="+1/2"/> > </OPERATOR> > <OPERATOR name="n" matrixelement="N"/> > <OPERATOR name="n_up" matrixelement="(N+2*Sz)/2"/> > <OPERATOR name="n_down" matrixelement="(N-2*Sz)/2"/> > </SITEBASIS> > > <BASIS name="Kondo lattice"> > <SITEBASIS ref="fermion"> > <PARAMETER name="local_maximum" value="local_max#"/> > <PARAMETER name="local_max#" value="local_max"/> > <PARAMETER name="local_max" value="2"/> > <PARAMETER name="local_minimum" value="local_min#"/> > <PARAMETER name="local_min#" value="local_min"/> > <PARAMETER name="local_min" value="0"/> > </SITEBASIS> > <CONSTRAINT quantumnumber="N" value="N_total"/> >  > </BASIS> > > <BONDOPERATOR name="exchange" source="x" target="y"> > Sz(x)*Sz(y)+1/2*(Splus(x)*Sminus(y)+Sminus(x)*Splus(y)) > </BONDOPERATOR> > > <BONDOPERATOR name="fermion_hop" source="x" target="y"> > > > cdag_up(x)*c_up(y)+cdag_up(y)*c_up(x)+cdag_down(x)*c_down(y)+cdag_down(y)*c_down(x) > </BONDOPERATOR> > > <HAMILTONIAN name="Kondo lattice"> > <PARAMETER name="mu" default="0"/> > <PARAMETER name="t" default="1"/> > <PARAMETER name="J" default="1"/> > <BASIS ref="Kondo lattice"/> > <SITETERM type="0" site="i"> > -mu*n(i) > </SITETERM> > <SITETERM type="1"> > 0 > </SITETERM> > <BONDTERM type="0" source="i" target="j"> > -t*fermion_hop(i,j) > </BONDTERM> > <BONDTERM type="1" source="i" target="j"> > J*exchange(i,j) > </BONDTERM> > </HAMILTONIAN> > > </MODELS> > > --------------------------CHAIN LATTICE IN my_lattices.xml > -------------------------------------- > > <LATTICES> > > <LATTICE name="chain lattice" dimension="1"> > <PARAMETER name="a" default="1"/> > <BASIS><VECTOR>a</VECTOR></BASIS> > <RECIPROCALBASIS><VECTOR>2*pi/a</VECTOR></RECIPROCALBASIS> > </LATTICE> > <UNITCELL name="fermion" dimension="1"> > <VERTEX type="0"/> > <VERTEX type="1"/> > <EDGE type="0"><SOURCE vertex="1" offset="0"/><TARGET vertex="1" > offset="1"/></EDGE> > <EDGE type="1"><SOURCE vertex="1" offset="0"/><TARGET vertex="2" > offset="0"/></EDGE> > </UNITCELL> > <LATTICEGRAPH name = "chain lattice"> > <FINITELATTICE> > <LATTICE ref="chain lattice"/> > <PARAMETER name="L" default="4"/> > <EXTENT size="L"/> > <BOUNDARY type="open"/> > </FINITELATTICE> > <UNITCELL ref="fermion"/> > </LATTICEGRAPH> > > </LATTICES> > > > ---------------------------------------END------------------------------------------------------- > > Best, > Bo-Nan > > -- > Stay foolish,Stay hungry. >

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Nearest Neighbor Correlation function
by Billa 15 Mar '13

15 Mar '13

Hi all, I have been trying to set up a classical Monte Carlo simulation with a square lattice Heisenberg model. I am interested in measuring nearest neighbor correlation functions of the type <S^z _i S^z _(i+1)>. How can I define such a measurement? I saw in the ALPS DMRG tutorial that correlation measurements can be set up by inserting the MEASURE_CORRELATIONS command into the parameter file, however this does not seem to work for the Heisenberg model. How can I produce measurements of <S^z _i S^z _(i+1)> type correlators? As a related question, where can I see how the Heisenberg model is defined in ALPS? I found definitions of the Ising, spin and various other models in the models.xml file, but there was no reference to Heisenberg. Finally, in the tutorials on classical Monte Carlo the employed update procedure is referenced as 'cluster'. Which cluster update algorithm is used in alps precisely? I couldn't find this info in the documentation. Thanks in advance for all replies! Billa

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the right way to define a harmonic trap
by Bo-Nan JIANG 15 Mar '13

15 Mar '13

Hi,all I am confused about how to define a harmonic trap in ALPS, shall I add it directly to the SITETERM as follows? <SITETERM type="0" site="i"> <PARAMETER name="x" value="i"/> -mu*n(i)+V*n(i)*(x-L/2)*(x-L/2) </SITETERM> where parameters mu and V, operator n(i) are defined in my_models.xml but, L the length of lattice is defined in a separate independent file my_lattices.xml. Is this kind of definition of harmonic trap OK in ALPS? Bo-Nan -- Stay foolish,Stay hungry.

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TEBD in ALPS
by Bo-Nan JIANG 15 Mar '13

15 Mar '13

Hi, all I install the ALPS 2.1 in Windows XP, and find the TEBD function disable. So, I search the C:\Progam File\ALPS\bin\ , there are dmrg.exe, dmft.exe, but just no tebd.exe, I want to know why and how to fix this problem up. Bo-Nan -- Stay foolish,Stay hungry.

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Re: [ALPS-users] Comp-phys-alps-users Digest, Vol 84, Issue 11
by Bo-Nan JIANG 14 Mar '13

14 Mar '13

Hi, Matthias this is the custom lattice I am using: -------------------------------------my_lattices.xml---------------------------------------------------------------------- <LATTICES> <LATTICE name="chain lattice" dimension="1"> <PARAMETER name="a" default="1"/> <BASIS><VECTOR>a</VECTOR></BASIS> <RECIPROCALBASIS><VECTOR>2*pi/a</VECTOR></RECIPROCALBASIS> </LATTICE> <UNITCELL name="fermion" dimension="1"> <VERTEX type="0"/> <VERTEX type="1"/> <EDGE type="0"><SOURCE vertex="1" offset="0"/><TARGET vertex="1" offset="1"/></EDGE> <EDGE type="1"><SOURCE vertex="1" offset="0"/><TARGET vertex="2" offset="0"/></EDGE> </UNITCELL> <LATTICEGRAPH name = "chain lattice"> <FINITELATTICE> <LATTICE ref="chain lattice"/> <PARAMETER name="L" default="4"/> <EXTENT size="L"/> <BOUNDARY type="periodic"/> </FINITELATTICE> <UNITCELL ref="fermion"/> </LATTICEGRAPH> </LATTICES> ------------------------------------end of my_lattices.xml------------------------------------------------------------------- Bo-Nan 2013/3/13 <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. "Kondo Lattice" model in ALPS (Bo-Nan JIANG) > 2. question about fermion model (Bo-Nan JIANG) > 3. Re: question about fermion model (Matthias Troyer) > 4. Re: "Kondo Lattice" model in ALPS (Matthias Troyer) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 13 Mar 2013 08:48:42 +0800 > From: Bo-Nan JIANG <bonanjiang(a)gmail.com> > To: "comp-phys-alps-users(a)lists.phys.ethz.ch" > <comp-phys-alps-users(a)lists.phys.ethz.ch> > Subject: [ALPS-users] "Kondo Lattice" model in ALPS > Message-ID: > < > CADqUQBOJNvgOfDGkTY3GUPbu9sAieKzNEJ3xeuDb67v0vDDvZw(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Hi, ALPS developers and users > > When I did DMRG with the "Kondo lattice" model in ALPS lib, the computer > returned error: > "Site basis for type 2 not found and no default exists." > I do not know whether it is the problem of my code or the ALPS model > itself, so dear developer, is this "Kondo lattice" model in your lib being > tested by DMRG? If it is not, can you test it and tell my whether it works? > (take you five minutes most) Thus, I can make up my mind whether I should > find other way of coding or continue debuging this code which returns > problem. This is really a big help! > > Bo-Nan > > -- > Stay foolish,Stay hungry. >

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"Found two lowering operators"
by Mateusz Łącki 14 Mar '13

14 Mar '13

Dear All, I am creating a model which is meant to be simulated with qmc. But when using worm I get: "Found two lowering operators" when using dirloop_sse: "Found two raising operators." To be frank I have no idea what is the problem. These statements are true: i have several lowering/raising operators. Is this unsupported or even worse: difficult? Best regards, Mateusz Łącki

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"Kondo Lattice" model in ALPS
by Bo-Nan JIANG 13 Mar '13

13 Mar '13

Hi, ALPS developers and users When I did DMRG with the "Kondo lattice" model in ALPS lib, the computer returned error: "Site basis for type 2 not found and no default exists." I do not know whether it is the problem of my code or the ALPS model itself, so dear developer, is this "Kondo lattice" model in your lib being tested by DMRG? If it is not, can you test it and tell my whether it works? (take you five minutes most) Thus, I can make up my mind whether I should find other way of coding or continue debuging this code which returns problem. This is really a big help! Bo-Nan -- Stay foolish,Stay hungry.

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question about fermion model
by Bo-Nan JIANG 13 Mar '13

13 Mar '13

Hi,all I am always wondering if I defined the quantum numbers of the fermion site basis in the following way, would there be a negative Ndown number (for example, with N=0, Nup=1)? <QUANTUMNUMBER name="N" min="0" max="2"/> <QUANTUMNUMBER name="Nup" min="0" max="1"/> <QUANTUMNUMBER name="Ndown" min="N-Nup" max="N-Nup"/> Bo-Nan -- Stay foolish,Stay hungry.

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DMRG in Kondo Lattice
by Bo-Nan JIANG 12 Mar '13

12 Mar '13

Hi,all I come up with a problem when I calculate the gap of Kondo lattice model with DMRG in ALPS, the computer returns: "Site basis for type 2 not found and no default exists." And I am so confused, because the model I use (Model="Kondo lattice") is from the ALPS lib. So, can you guys tell me why this error message shows up? Does the mentioned error come from the model part or the lattice part? Bo-Nan -- Stay foolish,Stay hungry.

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Comp-phys-alps-users