August 2014 - Comp-phys-alps-users

dimerized chain with DMRG
by Stone, Matthew B. 17 Aug '14

17 Aug '14

Thank you for the response regarding my prior question regarding the dimerized chain. To follow up, I would like to ask a few more novice questions. Does the DMRG ALPS routine calculate the momentum for one-dimensional systems? Does the following unitcell definition have the appropriate open boundary conditions for efficient use of the DMRG routines? <UNITCELL name="anisotropic1d" dimension="1"> <VERTEX/> <EDGE type="0"> <SOURCE vertex="1" offset="0"/> <TARGET vertex="2" offset="0"/> </EDGE> <EDGE type="1"> <SOURCE vertex="2" offset="0"/> <TARGET vertex="1" offset="1"/> </EDGE> </UNITCELL> Thank you, Matthew Stone

2 1

Help regarding sparse diagonalization
by Sriluckshmy Viswanathan 15 Aug '14

15 Aug '14

Hi, I am writing a code for the computing gap in kitaev-heisenberg model on the honeycomb lattice using sparse diagonalization. When the coupling for the kitaev term is zero the model patch that I wrote should match the model that is inbuilt. But that doesnt happen. I may have made a mistake in the model patch which is as follows. <HAMILTONIAN name="kitaev heisenberg"> <PARAMETER name="J" default="1"/> <PARAMETER name="Jz" default="0"/> <PARAMETER name="Jx" default="0"/> <PARAMETER name="Jy" default="0"/> <BASIS ref="spin"/> <BONDTERM source = "i" target="j"> J*Sz(i)*Sz(j) +J*exchange_xy(i,j) </BONDTERM> <BONDTERM type="0" source="i" target="j"> Jz*Sz(i)*Sz(j) + J*Sz(i)*Sz(j) +J*exchange_xy(i,j) </BONDTERM> <BONDTERM type="1" source="i" target="j"> Jx*Sx(i)*Sx(j) + J*Sz(i)*Sz(j) +J*exchange_xy(i,j) </BONDTERM> <BONDTERM type="2" source="i" target="j"> Jy*Sy(i)*Sy(j) + J*Sz(i)*Sz(j) +J*exchange_xy(i,j) </BONDTERM> </HAMILTONIAN> I have also attached the output that I got in dat format. Could you please help me with this problem? Sriluckshmy

2 7

query regarding the units
by D´Souza, Sunil Wilfred 14 Aug '14

14 Aug '14

Dear Alps users, In the tutorial "MC-07 Phase transition in the Ising model", what is the unit in which the temperature is defined. with best regards Sunil

2 1

Error: Cannot find a file named pyalea_c.so
by Niraj Ghimire 13 Aug '14

13 Aug '14

Dear alps users, I was able to build ALPS and everything worked except that I got one error when I used the command "make install." The error message reads: CMake Error at lib/pyalps/cmake_install.cmake:42 (FILE): file INSTALL cannot find "/home/guest/buildalps/lib/pyalps/pyalea_c.so" where guest is my user account and buildalps is my build directory for ALPS. I have no idea what this file (pyalea_c.so) is and why I am getting this error. Please help me. Thanks, Niraj

3 29

REQUEST
by Niraj Ghimire 12 Aug '14

12 Aug '14

Dear alps users/developers, I humbly request you to write stuffs on the ALPS webpage, especially on the "Build ALPS from source" section, in a clearer/nicer way. For linux and alps beginners, it's sometimes difficult to understand what different command lines (e.g., cmake -D Boost_ROOT_DIR:PATH...., cmake -DCMAKE_INSTALL_PREFIX...., etc.) do and how one can really use them. Please elaborate every step so that even beginners don't spend too much time to understand what they are doing. Thank you, Niraj

2 3

underflow error reading the file
by Georgios Zavitsanos 12 Aug '14

12 Aug '14

Hello, I am trying to run my first example using ALPS code for Ising model... So, reading the tutorials, I wrote the parameter-input- file (parm1a), I converted to the file parm1a.in.xml and then I tried to run the command: spinmc --Tmin 10 --write-xml parm1a.in.xml but, I received the error message: basic_filebuf::underflow error reading the file . I installed the ALPS packages before one week, so maybe there is something new in writing the input files ? Any ideas would be very helpful... Thank you in advance. Best regards, Giorgos

2 2

Building alps from source
by Niraj Ghimire 08 Aug '14

08 Aug '14

Dear alps users, I have been trying to build alps from source on Fedora 20 and I am having issues. I am new to alps and Linux OS itself, so I am spending too much time. I followed the instructions on "Get dependent libraries and tools on Fedora 20" and that was easy to understand and work out. Now I am on "Build ALPS". Either the instructions on "Build ALPS" are not sufficient for a Linux beginner like me or I am not being able to follow them. Please provide me with detailed instructions/guidelines or anything that helps, I will truly appreciate it. Thanks, Niraj

4 11

site dependent potential
by benoît grémaud 07 Aug '14

07 Aug '14

Dear All, If I got it correctly, to have a site dependent potential one can use the inhomogeneous lattice and specify 'mu' as a function of space. However, it seems to be restricted to alps-defined functions (including rand()), but I couldn't find a list of them. For instance, is there a delta-kronecker function or a step function available? As an alternative, is there a way to pass a well defined set of numerical values? For instance to tune the boundary chemical potential only, I had to follow the tutorial and create a special lattice with different site type at the boundary. Is it the only way? thank you for your reply. best, Benoît -------------------- Researcher at CNRS, Laboratoire Kastler Brossel (Paris, France) and UMI Merlion-MajuLab (Singapore) Visiting Associate Professor at the Centre for Quantum Technologies (NUS, Singapore)

1 0