real analysis – Determine if a multivariate function can have a point of equilibrium

Suppose we have a function $ f: mathbb {R} ^ n longrightarrow mathbb {R} $ it is the result of the composition of two functions $ g: mathbb {R} ^ n longrightarrow mathbb {C} ^ {2n} $ and $ h: mathbb {C} ^ {2n} longrightarrow mathbb {R} $ such as $ f = h (g (x_1, x_2, …, x_n)) $.

Is it possible to know if the function $ f $ has saddle points.

Context: the function $ f $ is the objective function of an optimization problem. Function $ g $ takes the entries of $ mathbb {R} ^ n $ in the Hilbert space $ mathbb {C} ^ {2n} $ and its output (a pure quantum state in fact) is transmitted to $ h $ which calculates the wait and returns a unique real number.

Yes $ f $ is a convex function, each local minimum is a global minimum and do not worry that the optimizer remains stuck in the local minimum. If not, how to show that it is not convex and can have saddle points?

algorithms – Clustering of point clouds based on a similarity less than $ O (n ^ 2) $

I do not know if this is the right place to ask this question, but that's it.

Suppose I have a set of 2D points data including face landmarks and want to group them according to the similarity in order to be able to refer to a notion of "prototype". a facial expression.

As a measure between one set of points and another, I could use a sum of Euclidean distances.

Is it possible to get a set of prototypes without going through the landmarks? $ O (n ^ 2) $ time?

To better explain what I think, suppose I process a video frame by frame.

I start with the landmarks of the first image, and put it in my prototype list because I have no other reference.

Then, for each next image, I compare it to the first "prototype". If it's below a certain similarity threshold, I guess it's not unique enough and skips it. Therefore, until I find a set of quite different landmarks, now I have two "prototypes".

From that moment, I have to perform the similarity check with two "prototypes", etc.

Another caveat is that I would also like to be able to store the "prototype" that the current frame fits the most.

I will also have to make a second pass in a second clip for a similar correspondence with the "prototypes" identified during the first pass.

Is there a more effective way to do this, other than the naive approach?

Very fast video on YouTube / Marketing and social promotion guarantee 1000 to 10 $

Ultra Fast YouTube Video / Social Marketing and Promotion Guarantee 1000

Hello customer
Sir, I saw your work and realized that I am very interested in this work. If you give me a job, I can do it very well.If you have any questions about this, please contact me.
_____-__ —– __________> Super Fast Video Marketing and Promotion of YouTube videos guaranteeing high retention. Promotion of video promotion promotion + Non-guaranteed decline via a real audience.

✔ Can order multiple quantities
✔ Marketing 100% safe and natural
✔ 90 Day Refill Guarantee
✔ The counter of your video will reflect the audience reached.


Networking – How to get a DHCP IP address running on a WiFi point of access using an adb shell?

I connect to my WiFi network from the adb shell with the help of the following command:

iw dev wlan1 connect -w WiFi-AP

A DHCP server is also running on the point of access, but each time I try to get an IP address using the dhclient -v wlan1, I get the following error:

sh: dhclient: not found

Is there a way to install dhclient on Android 8.1 or is there another way to request an IP address from the DHCP server via a wlan interface?

python – An end-of-extraction point returned file data multiplied by the parameters of a query

Does anyone know how to avoid mistakes: You got AttributeError when trying to get a value for the data_from_file field on the DataSerializer serializer in the code below?

Data class (models.Model):
data_from_file = models.CharField (max_length = 20)

DataSerializer class (serializers.ModelSerializer):
Meta class:
model = data
fields = __ all __ & # 39; __

DataView class (ListAPIView):
serializer_class = DataSerializer

def get_queryset (auto):
mult = self.request.query_params.get (# mult, #)
y = np.loadtxt ('media / data_vv.txt')[:10]
        x = list (range (len (y)))

if mult is not None:
y * = float (mult)

y = list (y)
data = {x, x, y: y}
content = JSONRenderer (). render (data)
content = Data (data_from_file = content) ()
serializer = DataSerializer (content)

returns JsonResponse (, safe = False)

[WTS] N ° 1 of CLOUD host – (managed and unmanaged)

For webmasters looking for reliable solutions CLOUD Accommodation Offers, is the best solution.

HostForWeb, Inc As the premier hosting provider in New York, it provides reliable and scalable solutions for customers of all sizes and services. We started this business with one goal in mind: to provide reliable hosting solutions coupled with excellent customer service.

What is cloud hosting?

Cloud hosting technology is the latest generation of web hosting, thanks to which customers can rent a virtualized and scalable structure dynamically as needed. It surpasses all other solutions in terms of speed, reliability, price and convenience. Unlike a dedicated server, with which users must pay for all server resources to ensure their availability during periods of high traffic, the cloud server makes them resources available on request and puts them to use elsewhere when traffic drops, which means you only pay for what you use.

CHECK-OUT Hostforweb VPS CLOUD Solutions :

Storage – 30 GB SSD
Bandwidth – 2 TB
RAM – 1 GB
1 vCPU
Price per month – $ 10

Storage – 40 GB SSD
Bandwidth – 3 TB
RAM – 2 GB
1 vCPU
Price per month – $ 20


Managed cloud hosting This solution will bring you all the benefits of a cloud server: total scalability, rapid deployment of IT resources, high performance and reliable service. In addition, it will save you the hassle of managing your server because we will do all the work. Go ahead, enjoy us.

CHECK-OUT Hostforweb Managed cloud solutions :

Departure cloud
Storage – 60 GB SSD
Bandwidth – 2000GB
RAM – 2048MB
cVPUs / Ghz: 2 / 1,8Ghz
Price per month – $ 41.96

Storage – 80 GB SSD
Bandwidth – 3000 GB
RAM – 4096MB
cVPUs / Ghz: 4 / 3.6Ghz
Price per month – $ 55.96


Why choose us?

  • Self-repairing material – We store your cloud server centrally, without any connection to the cloud nodes on which it runs, and back it up with a seamless failover process. In the highly unlikely case of a node failure, your system is automatically restarted.
  • Scale on Demand – Whatever the computing resources required (RAM / CPU / Storage), we make them automatically available on demand. Your site will never drop because of the heavy traffic.
  • The fastest in the sector – Our network infrastructure is redundant, transparent and always available, offering you a solution 10 times faster than an average dedicated server.
  • Free Migration Assistance – If you have a pre-existing site with another hosting company, we will be happy to take care of your migration process, for free. Our customer service representatives are available every hour of the day, every day of the week.
  • 24/7/365 Customer Support – We want to be available to our customers when they need us, and not a moment later. No matter when you want help with your server, we'll be there – that's a promise.
  • Satisfaction guaranteed – We are so confident that you will love our services that we offer you a 30 day money back guarantee. No questions asked.

We enjoyed very much growth over the yearsbut this goal has never changed. we can guarantee no matter how much we grow or what success we have, we will never be strayed from our goal. We owe everything to our customers and we will continue to show our appreciation for our reliable solutions and our high-end service.

Contact information:
Mailing / Delivery Address: HostForWeb, 56 Leonard Street, Suite 21A-East, New York, NY 10013
For more details on the contacts, visit:

With HostForWeb cloud servicesyou'll benefit from the highest performance, security, capabilities, and fault tolerance on the market. We know you deserve the best for your accommodation, so why not choose us?


mount point – mount / unmount the storage device, which happens to files

I have trouble understanding the following.

In / etc / fstab, I mounted an external storage volume with:

// external_backup_volume user cifs = xyz, password = xyz, users 0 0

Every day, I sync files from a local folder to the mount point:

rsync --progress -arnz / backup / home / me / external_backup_volume

When I dismount / home / me / external_backup_volume I always see subdirectories and folders. Are files still available even when the backup storage is unmounted? Of ls -al it looks like but if i check df with the mounted drive and not the local disk usage of / dev / md2 do not change:

me @ Ubuntu-1804-bionic-64-minimal: ~ $ df -h
Size of file system used Usage used% Mounted
udev 16G 0 16G 0% / dev
tmpfs 3.2G 1.1M 3.2G 1% / run
/ dev / md2 436G 105G 310G 26% /
tmpfs 16G 8.0K 16G 1% / dev / shm
tmpfs 5.0M 0 5.0M 0% / run / lock
tmpfs 16G 0 16G 0% / sys / fs / cgroup
/ dev / md1 488M 204M 259M 45% / boot
tmpfs 3.2G 0 3.2G 0% / run / user / 1000
// 100G 46G 55G 46% / home / me / external_backup_volume

me @ Ubuntu-1804-bionic-64-minimal: ~ $ umount / home / me / external_backup_volume
me @ Ubuntu-1804-bionic-64-minimal: ~ $ df -h
Size of file system used Usage used% Mounted
udev 16G 0 16G 0% / dev
tmpfs 3.2G 1.1M 3.2G 1% / run
/ dev / md2 436G 105G 310G 26% /
tmpfs 16G 8.0K 16G 1% / dev / shm
tmpfs 5.0M 0 5.0M 0% / run / lock
tmpfs 16G 0 16G 0% / sys / fs / cgroup
/ dev / md1 488M 204M 259M 45% / boot
tmpfs 3.2G 0 3.2G 0% / run / user / 1000

So, why do I always see the files when the drive is unmounted?

Disable the new Alfred 4 polling point feature

With Dash and other types of search engines, when I wanted to search something in Alfred 3, I added a question mark so that Alfred had no doubt that I wanted to do something. a search on that.

Now in Alfred 4, there is this new feature that allows you to search for Alfred's preferences by adding a query point. So my workflow is broken.

I have not been able to find out how to change the & # 39; for anything else or disable it completely. It comes in the middle. For example, this:

enter the description of the image here

Go to

How can I get rid of this feature?

BitMEX Premium Bot supports permanent API keys and is an excellent starting point for implementing your own trading strategies. – Advertising, offers

You can visit our group and view all Bitmex Premium Bot statistics –

If you want to profit from margin trading or leveraging, Bitmex is the best choice.

We do not simply post signals, but we also make sure that every signal is executed on your account.

We are the ideal solution for trading on Bitmex because we provide the best Bitmex bot called Bitmex Premium BOT.

With our Premium Bitmex Bot, you get the best independent transactions on your Bitmex account according to your quantity for consistent profit.

Become Pro and accumulate big profits on Bitmex through our Premium Bitmex Deluxe Group + Premium Bitmex Bot.

We have recently updated the statistics for June 2019, you can visit our group and view the complete statistics for 2019.


height of a point in the projective space

$ underline {Background} $:Let, $ X = {P_1, … P_s } $ to be a set of $ s $ distinct points of $ mathbb {P} ^ {n} = Proj (K[x_0,….,x_n]$, so we know that $ P_i $ are homogeneous prime ideals $ mathcal P_i $ that does not contain ideal ideal irrelevant.

$ underline {Question} $: why ht ($ mathcal P_i) = n $?

$ underline {Guess} $ : we know that, ht ($ mathcal P_i) + $ low K $[x_0,….,x_n]/ mathcal P_i = $ low K $[x_0,….,x_n] = n + 1 $but why dim K $[x_0,….,x_n]/ mathcal P_i = 1 $ ?

Any help from anyone is welcome.