Dear ALPS users/developers,
I have a quick question about the NONLOCAL parameter used in the worm algorithm. The ALPS-Wiki mentions it to be a compile time option that one must "undefine to speed up the code for local interactions". However when I run a simulation (linear chain of hardcore bosons with finite chemical potential) for a given chain size with and without this parameter un-defined, the results are quite different. Secondly, the results for the runs with NONLOCAL=0 for different chain sizes are quite comparable to each other (though not exactly equal) and to the exact result for a single-site calculation (again though not exactly equal).
I am trying to understand what this parameter does and why the results change when it is set versus unset; any ideas will be appreciated.
Thanks, Vipin
Which model are you running it for?
Matthias
On Sep 16, 2011, at 2:28 PM, Vipin Varma wrote:
Dear ALPS users/developers,
I have a quick question about the NONLOCAL parameter used in the worm algorithm. The ALPS-Wiki mentions it to be a compile time option that one must "undefine to speed up the code for local interactions". However when I run a simulation (linear chain of hardcore bosons with finite chemical potential) for a given chain size with and without this parameter un-defined, the results are quite different. Secondly, the results for the runs with NONLOCAL=0 for different chain sizes are quite comparable to each other (though not exactly equal) and to the exact result for a single-site calculation (again though not exactly equal).
I am trying to understand what this parameter does and why the results change when it is set versus unset; any ideas will be appreciated.
Thanks, Vipin
Prof. Troyer,
This is the hardcore boson model on a linear chain.
Vipin
On Fri, 16 Sep 2011, Matthias Troyer wrote:
Which model are you running it for?
Matthias
On Sep 16, 2011, at 2:28 PM, Vipin Varma wrote:
Dear ALPS users/developers,
I have a quick question about the NONLOCAL parameter used in the worm algorithm. The ALPS-Wiki mentions it to be a compile time option that one must "undefine to speed up the code for local interactions". However when I run a simulation (linear chain of hardcore bosons with finite chemical potential) for a given chain size with and without this parameter un-defined, the results are quite different. Secondly, the results for the runs with NONLOCAL=0 for different chain sizes are quite comparable to each other (though not exactly equal) and to the exact result for a single-site calculation (again though not exactly equal).
I am trying to understand what this parameter does and why the results change when it is set versus unset; any ideas will be appreciated.
Thanks, Vipin
with no interaction but the hard-core?
On Sep 16, 2011, at 4:51 PM, Vipin Varma wrote:
Prof. Troyer,
This is the hardcore boson model on a linear chain.
Vipin
On Fri, 16 Sep 2011, Matthias Troyer wrote:
Which model are you running it for?
Matthias
On Sep 16, 2011, at 2:28 PM, Vipin Varma wrote:
Dear ALPS users/developers,
I have a quick question about the NONLOCAL parameter used in the worm algorithm. The ALPS-Wiki mentions it to be a compile time option that one must "undefine to speed up the code for local interactions". However when I run a simulation (linear chain of hardcore bosons with finite chemical potential) for a given chain size with and without this parameter un-defined, the results are quite different. Secondly, the results for the runs with NONLOCAL=0 for different chain sizes are quite comparable to each other (though not exactly equal) and to the exact result for a single-site calculation (again though not exactly equal).
I am trying to understand what this parameter does and why the results change when it is set versus unset; any ideas will be appreciated.
Thanks, Vipin
Nearest neighbour interactions (V) are present along with a finite chemical potential. Test case: V/t = 10; mu/t = 2.5.
Vipin
On Fri, 16 Sep 2011, Matthias Troyer wrote:
with no interaction but the hard-core?
On Sep 16, 2011, at 4:51 PM, Vipin Varma wrote:
Prof. Troyer,
This is the hardcore boson model on a linear chain.
Vipin
On Fri, 16 Sep 2011, Matthias Troyer wrote:
Which model are you running it for?
Matthias
On Sep 16, 2011, at 2:28 PM, Vipin Varma wrote:
Dear ALPS users/developers,
I have a quick question about the NONLOCAL parameter used in the worm algorithm. The ALPS-Wiki mentions it to be a compile time option that one must "undefine to speed up the code for local interactions". However when I run a simulation (linear chain of hardcore bosons with finite chemical potential) for a given chain size with and without this parameter un-defined, the results are quite different. Secondly, the results for the runs with NONLOCAL=0 for different chain sizes are quite comparable to each other (though not exactly equal) and to the exact result for a single-site calculation (again though not exactly equal).
I am trying to understand what this parameter does and why the results change when it is set versus unset; any ideas will be appreciated.
Thanks, Vipin
Der Vipin,
Indeed the nonlocal V term will be ignored when you turn nonlocal terms off. Furthermore, for this model the dirloop code is better
Matthias
On Sep 16, 2011, at 17:47, Vipin Varma varma@th.physik.uni-bonn.de wrote:
Nearest neighbour interactions (V) are present along with a finite chemical potential. Test case: V/t = 10; mu/t = 2.5.
Vipin
On Fri, 16 Sep 2011, Matthias Troyer wrote:
with no interaction but the hard-core?
On Sep 16, 2011, at 4:51 PM, Vipin Varma wrote:
Prof. Troyer,
This is the hardcore boson model on a linear chain.
Vipin
On Fri, 16 Sep 2011, Matthias Troyer wrote:
Which model are you running it for?
Matthias
On Sep 16, 2011, at 2:28 PM, Vipin Varma wrote:
Dear ALPS users/developers,
I have a quick question about the NONLOCAL parameter used in the worm algorithm. The ALPS-Wiki mentions it to be a compile time option that one must "undefine to speed up the code for local interactions". However when I run a simulation (linear chain of hardcore bosons with finite chemical potential) for a given chain size with and without this parameter un-defined, the results are quite different. Secondly, the results for the runs with NONLOCAL=0 for different chain sizes are quite comparable to each other (though not exactly equal) and to the exact result for a single-site calculation (again though not exactly equal).
I am trying to understand what this parameter does and why the results change when it is set versus unset; any ideas will be appreciated.
Thanks, Vipin
comp-phys-alps-users@lists.phys.ethz.ch