Develop Reference

Visualizing circuits in qiskit with matplotlib

I'm learning how to use qiskit and I'm using the jupyter notebook, but everytime I try to visualize the circuit with the attribute draw I get this error:
import qiskit
from qiskit import *
from qiskit import IBMQ
qr = QuantumRegister(2)
cr = ClassicalRegister(2)
circuit = QuantumCircuit(qr, cr)
%matplotlib inline
circuit.draw(output='mpl')
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-8-bd220039ee1c> in <module>
----> 1 circuit.draw(output='mpl')
AttributeError: module 'qiskit.circuit' has no attribute 'draw'
I also try applying a Hadamard gate and I get:
circuit.h(qr(0))
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-59-c8b4318b743b> in <module>
----> 1 circuit.h(qr(0))
AttributeError: module 'qiskit.circuit' has no attribute 'h'

It seems that there is a name conflict. It is taking the circuit in from qiskit import circuit instead of circuit = ....
You just probably need to restat your notebook kernel.

Try another name for your circuit variable, right now python thinks you want the qiskit.circuit module to draw something. QuantumCircuit objects are the ones that have a draw method. You can see these two objects here if you call both, note I put one qubit and classical bit in the QuantumCircuit just per example as well you do not need the dots here it is just to make it more clear, just running circuit and QuantumCircuit(1,1) respectively would yield the same result.
You would get desired results if you tried a different variable name:
When I try using the variable name circuit it works for me, but try to use descriptive variable names that also could never be confused with modules or classes from the packages you import.
Also all your import statements can be combined into 1:
from qiskit import *
The star lets you import everything from qiskit including IBMQ. It can help you save a line or two.

Runtime error while executing code from google colab document for creating Deepfakes image animation

enter image description hereI'm getting runtime error while executing code from google colab document for creating Deepfakes image animation.
RuntimeError Traceback (most recent call last)
<ipython-input-5-dbd18151b569> in <module>()
1 from demo import load_checkpoints
2 generator, kp_detector = load_checkpoints(config_path='config/vox-256.yaml',
----> 3 checkpoint_path='/content/gdrive/My Drive/first-order-motion-model/vox-cpk.pth.tar')
10 frames
/usr/local/lib/python3.6/dist-packages/torch/cuda/__init__.py in _lazy_init()
188 raise AssertionError(
189 "libcudart functions unavailable. It looks like you have a broken build?")
--> 190 torch._C._cuda_init()
191 # Some of the queued calls may reentrantly call _lazy_init();
192 # we need to just return without initializing in that case.
RuntimeError: cuda runtime error (100) : no CUDA-capable device is detected at /pytorch/aten/src/THC/THCGeneral.cpp:47

You may be running on a colab environment that only has TPU's available and not GPU's in which case you need to utilize XLA with PyTorch. You might find this notebook and repository very helpful if this is the case:
https://colab.research.google.com/github/pytorch/xla/blob/master/contrib/colab/resnet18-training.ipynb
https://github.com/pytorch/xla

1.check the path weather the file exists or not
2.in your screen shot there is no drive mounted try checking it once
3.if top two are done still facing problem check with the file given is correct or not
Hope this is helpfu :)

Open3d Python, Type error using TriangleMesh.create_from_point_cloud_alpha_shape()

I am trying to use open3d to create an "alphahull" around a set of 3d points using TriangleMesh. However I get a TypeError.
import open3d as o3d
import numpy as np
xx =np.asarray([[10,21,18], [31,20,25], [36,20,24], [33,19,24], [22,25,13], [25,19,24], [22,26,10],[29,19,24]])
cloud = o3d.geometry.PointCloud()
cloud.points = o3d.utility.Vector3dVector(xx)
mesh = o3d.geometry.TriangleMesh.create_from_point_cloud_alpha_shape(pcd=cloud, alpha=10.0)
output:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: create_from_point_cloud_alpha_shape(): incompatible function arguments. The following argument types are supported:
1. (pcd: open3d.open3d.geometry.PointCloud, alpha: float, tetra_mesh: open3d::geometry::TetraMesh, pt_map: List[int]) -> open3d.open3d.geometry.TriangleMesh
The error says the object I am passing the function is the wrong type. But when I check the type I get this:
>>print(type(cloud))
<class 'open3d.open3d.geometry.PointCloud'>
Please can someone help me with this error?
Note: A comment on this post Python open3D no attribute 'create_coordinate_frame' suggested it might be a problem with the installation and that a solution was to compile the library from source. So I compiled the library from source. After this ran
make install-pip-package. Though I am not sure it completed correctly because I couldn't import open3d in python yet; see output of installation: https://pastebin.com/sS2TZfTL
(I wasn't sure if that command was supposed to complete the installation, or if you were still required to run pip? After I ran python3 -m pip install Open3d I could import the library in python.)

Bug in bindings of current release (v0.9.0):
https://github.com/intel-isl/Open3D/issues/1621
Fix for master:
https://github.com/intel-isl/Open3D/pull/1624
Workaround:
tetra_mesh, pt_map = o3d.geometry.TetraMesh.create_from_point_cloud(pcd)
mesh = o3d.geometry.TriangleMesh.create_from_point_cloud_alpha_shape(pcd, alpha, tetra_mesh, pt_map)

Python Import Error + DLL load failed + sys.path

in Python 2.7.10 Anaconda 2.3.0 (64-bit), if I write
sys.path.append('C:\\Anaconda\\sms-tools-master\\software\\models\\utilFunctions_C\\')
print sys.path
I get
C:\Anaconda\sms-tools-master\workspace\A1>python A1Part1.py
['C:\Anaconda\sms-tools-master\workspace\A1', 'C:\Anaconda\python27.zip',
'C:\Anaconda\DLLs', 'C:\Anaconda\lib', 'C:\Anaconda\lib\plat-win', 'C:\A
naconda\lib\lib-tk', 'C:\Anaconda', 'C:\Anaconda\lib\site-packages', 'C:\
Anaconda\lib\site-packages\Sphinx-1.3.1-py2.7.egg', 'C:\Anaconda\lib\site-
packages\cryptography-0.9.1-py2.7-win-amd64.egg', 'C:\Anaconda\lib\site-pack
ages\win32', 'C:\Anaconda\lib\site-packages\win32\lib', 'C:\Anaconda\lib
\site-packages\Pythonwin', 'C:\Anaconda\lib\site-packages\setuptools-17.1.
1-py2.7.egg', 'C:\Anaconda\sms-tools-master\software\models\utilFunctions_C
\']
Is this absolute way of adding to sys.path correct? Is there a relative way?
In the next line of python code I wrote
from utilFunctions_C import wavread
I instantly get
ImportError: cannot import name wavread
if I run the code in cmd but if I run the code inside IDLE I get:
['C:\Anaconda\sms-tools-master\workspace\A1',
'C:\Python27\Lib\idlelib', 'C:\Windows\system32\python27.zip',
'C:\Python27\DLLs', 'C:\Python27\lib',
'C:\Python27\lib\plat-win', 'C:\Python27\lib\lib-tk',
'C:\Python27', 'C:\Python27\lib\site-packages',
'C:\Anaconda\sms-tools-master\software\models\utilFunctions_C\']
Traceback (most recent call last): File
"C:\Anaconda\sms-tools-master\workspace\A1\A1Part1.py", line 8, in
from utilFunctions_C import wavread ImportError: DLL load failed: %1 is not a valid Win32 application.
So why there is a difference and how to tackle this issue? Thnx!

I commented
from utilFunctions_C import wavread
and used
from scipy.io.wavfile import read
Now my code is okay. I found that
utiLFunctions.wavread() is a wrapper that uses scipy.io.wavfile.read()
and scales the data to floating point between -1 and 1. If you open up
utilFunctions.py you will see that.
You can use scipy.io.wavfile.read as well, as long you scale the data
correctly looking at the datatype in the wav file. Due to scaling, for
wav files that store samples as int16, you will see that
scipy.io.wavfile.read returns values will be 32767 times the values
returned by utilFunctions.wavread
Lectures used the function to explain the process more explicitly.
Once you have got it, you can use the wrapper utilFunctions.wavread
for the rest of the course and in practical applications.
Scroll in
https://class.coursera.org/audio-002/forum/search?q=Cannot+import+name+wavread#15-state-query=wavread&15-state-page_num=1
for more details.

Loading Compiled Matlab Shared Library in Python Using Ctypes

I am trying to do Incomplete Cholesky Decomposition in Python, but no direct Python package I can find.
Since the most available codes I can find online are written in Matlab, I want to take a detour by
compiling the matlab code to a shared library (I am using Mac OS and MATLAB_R2014a, so it should produce .dylib file)
load library in Python by using Ctypes
The following lists the detailed steps:
0. Download Matlab Source Code
The code can be downloaded from F. Bach's webpage link to zip file, which contains the following files:
panc:csi-1.0 panc25$ ls
center.m csi.dll csi.mexglx csi_gaussian.dll csi_gaussian.mexglx readme.txt
csi.c csi.m csi_gaussian.c csi_gaussian.m demo_csi.m sqdist.m
1. Compiling the matlab code to a shared library
Then by following this post, I run the command:
mcc -v -W cpplib:libcsi -T link:lib csi
After around a minute, the terminal prints MEX completed successfully and in my folder there are
panc:csi-1.0 panc25$ ls
center.m csi.m csi_gaussian.dll demo_csi.m libcsi.exports readme.txt
csi.c csi.mexglx csi_gaussian.m libcsi.cpp libcsi.h sqdist.m
csi.dll csi_gaussian.c csi_gaussian.mexglx libcsi.dylib mccExcludedFiles.log
where libcsi.dylib is the shared library I want.
2. Loading library in Python
Then I open IPython and try to load the library:
In [1]: import ctypes
In [2]: ctypes.C
ctypes.CDLL ctypes.CFUNCTYPE
In [2]: ctypes.CDLL('libcsi.dylib')
---------------------------------------------------------------------------
OSError Traceback (most recent call last)
<ipython-input-2-b6d0c1a91651> in <module>()
----> 1 ctypes.CDLL('libcsi.dylib')
/Users/panc25/anaconda/lib/python2.7/ctypes/__init__.pyc in __init__(self, name, mode, handle, use_errno, use_last_error)
363
364 if handle is None:
--> 365 self._handle = _dlopen(self._name, mode)
366 else:
367 self._handle = handle
OSError: dlopen(libcsi.dylib, 6): Library not loaded: #rpath/libmwmclmcrrt.8.3.dylib
Referenced from: /Users/panc25/Downloads/csi-1.0/libcsi.dylib
Reason: image not found
This problem persists even after I replace file name in ctypes.CDLL('libcsi.dylib') with the full path.
So I am confused. The shared library is there, but why Python says "image not found"?
BTW
SInce the source code also provide C implementation through mex.h, I also tried to first create a .mex file, then compile the .mex to a shared library as follows:
panc:csi-1.0 panc25$ mex csi.c
which created the csi.mexmaci64 file. Then according to this link, I called:
panc:csi-1.0 panc25$ mcc -B csharedlib:csi2 csi.mexmaci64
which produced csi2.dylib file.
But when I tried to load it in Python, I had the same error.
Could anyone let me know what is wrong?

I would avoid Matlab altogether, and instead use the Incomplete Cholesky Decomposition available in PyMC2:
from pymc.gp.incomplete_chol import ichol_full
The f2py wrapped Fortran code, that was actually adapted from a MEX file, can be found here. So you could use this independently of PyMC2 if need be.
If you are interested, you could also propose to add this function to scipy (see this githib issue ).