I am a PhD student of Hong Kong University of Science and Technology. I
want to use KWANT to caculate Hall resistance of a Hall bar structure.We
can get the conductance between 6 electrodes, but how to get hall
resistance? Can you give me some help? Thank you very much.
Dear kwant users,
we have posted new instructions for installing kwant on Windows on the
kwant website: http://www.kwant-project.org/install
The old instructions do not work any more, as the format of the python
packages on Christoph Gohlke's webpage have changed.
the kwant team
I have a question about the figure plotting of kwant, or maybe it is just a
python question. When we plot more than one figures in kwant, we need to
close the first figure to let the second one start to be plotted. Can we
plot all the figures without manually closing the figure window? Maybe a
silly question, i am really not good at python.
Dear kwant users and developers,
this is my first post to this list, I'm a PhD student from Berlin.
Currently I'm trying to implement a lattice model of a pyrochlore slab
I found a (more or less straightforward) way to introduce periodic
boundary conditions in the system in the maillinglist archive.
This works very nicely as long as I keep the periodicity along a lattice
But I run into problems when I choose different directions: Most of the
time all solvers fail with a
"LinAlgError: QZ iteration failed to converge in zgges".
I know about this post
but in my case it occurs not only for a band bottom, but for a range of
To give you all the details I prepared a Ipython notebook that you can
(Note that the inclusion of complex next-nearest-neighbor hopping is
crucial to produce the error, I tried to create the shortest example
which reproduces my problem).
Do you have any idea how to circumvent this problem?
Is it somehow related to
problem in Lapack?
I would be thankful for any hint,
I have installed (in non standard directories)
* MUMPS 5.0.1
* SCOTCH 6.0.4
* METIS 5.1.0
resulting in following libs
libcmumps.a libdmumps.a libmpiseq.a libmumps_common.a libpord.a libsmumps.a libzmumps.a
* libesmumps.a libptesmumps.a libptscotch.a libptscotcherr.a libptscotcherrexit.a libscotch.a libscotcherr.a libscotcherrexit.a libscotch_group.a
I use Intel’s icc/ifort/MKL.
When building kwant, the output shows "User-configured MUMPS", no errors.
I use following build.conf file:
libraries = zmumps mumps_common pord metis esmumps scotch scotcherr mpiseq
library_dirs = $MUMPS/lib $METIS/lib $SCOTCH/lib
libraries = mkl_intel_lp64 mkl_sequential mkl_core mkl_def
library_dirs = $IMKL/mkl/lib/intel64
extra_link_args = -Wl,-rpath=$IMKL/mkl/lib/intel64
However, it seems something is going wrong since MUMPS cannot be loaded. I tried both kwant 1.0.5 and 1.1.1.
>>> from scikits import umfpack
>>> import kwant
[…]/lib/python2.7/site-packages/kwant-1.1.1-py2.7-linux-x86_64.egg/kwant/solvers/default.py:18: RuntimeWarning: MUMPS is not available, SciPy built-in solver will be used as a fallback. Performance can be very poor in this case.
>>> from kwant.linalg import mumps
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "[…]/lib/python2.7/site-packages/kwant-1.1.1-py2.7-linux-x86_64.egg/kwant/linalg/mumps.py", line 17, in <module>
from . import _mumps
ImportError: […]/lib/python2.7/site-packages/kwant-1.1.1-py2.7-linux-x86_64.egg/kwant/linalg/_mumps.so: undefined symbol: scotchfdgraphcorderinit_
Any idea how to solve this problem?
Thanks in advance!
I use python 2.7 and pip from homebrew:
pip 7.1.2 from /usr/local/lib/python2.7/site-packages (python 2.7)
I also verified that installing from the source gives the same error. However, simply putting
solves the problem: "python setup.py build" runs smoothly.
I installed kwant 1.0.3 on mac os with
pip install kwant
Since this version, the new ones point to /usr/... instead /usr/local/... to find numpy libraries:
kwant/_system.c:255:10: fatal error: 'numpy/arrayobject.h' file not found
and the installation fails. The correct path is of the form:
Alberto Verga <mailto:Alberto.Verga@univ-amu.fr>
Campus St Jérôme, service 142
13397 Marseille cedex 20, France
I request you all to suggest some EASY-TO-START material/theory for
understanding the concepts behind Kwant. I need to learn the basics before
I would be glad if you could provide any ppts. I want to feel theoretically
confident before starting Kwant.
*Dr. Siddheshwar chopra,*
*M.Sc., Ph.D (Physics)Assistant Professor (Physics),*
*Amity University, Noida, India.*
It has reference to 2.3.2 of "More interesting systems :Kwant 1.0.3 documentation". I have some
confusions and/or misconceptions in the code of that quantum well study. These are as under:
(i) in segment "# potential profile" does the scattering region mean one dimensional? I have the idea
that the scattering region is two dimensional free and one dimensional bound and for size effect in
this dimension several channels evolve. Scattering therefore happens from channel(s) in one lead to
channel(s) in other lead with due attention to the quantized bound levels.
I fail to extract this underlying physics in this part of the program.
(ii) in segment "def onsite(site,pot=0):" are the onsite Hamiltonians given to the lattice sites of
two dimensional region?
I am misunderstood and at a loss.
I want to be clear and specific which dimension is restricted to evolve the bound states? and which the
other two free making a real quantum well. Once I understand that I may manipulate the number of
channels and number of bound states to modify the transport.
Also, if I am not wrong, the ballistic transport should be considered in the leads only; then it is the
lead only where dimensionality should be considered! but I do not find this method in the lead.
May be I am wrong! still then I await your wise answer to my confusions.