Tag: expected

trace: Target Units do not work as expected in an InterpolatingFunction

Short version: My understanding of the use of TargetUnits in a plot statement is that if the function being traced has units, MMA will attempt to convert the output of that function to the unit form specified by TargetUnits. However, it does not seem to be doing that. What am I missing?

Context: I'm writing some general routines to analyze a particular type of differential equation system. These may be of arbitrary complexity, although with a well-defined relationship between units. I have not been able to get MMA to run NDSolve on systems that include units, so I have developed a way to convert all units to YES, remove the units, do NDSolve and then re-add the appropriate units to the resulting InterpolatingFunctions. When I look at the individual values ​​that result from those interpolation functions, the results look good. But when I try to plot the results using TargetUnits, they do not.

Simplified example:

rateeq(t_) = {a'(t) == k1 b(t) + k2 a(t) b(t) + k3 b(t)^2, 
              b'(t) == -k1 b(t) - k2 a(t) b(t) - k3 b(t)^2};
initCond(t_) = {b(t) == Quantity(10^-9, "Molar"), 
                a(t) == Quantity(10^-5, "Molar")};
rateConstValues = {k1 -> Quantity(7000, 1/"Seconds"), 
                   k3 -> Quantity(5.4 10^9, 1/("Molar" "Seconds")), 
                   k2 -> Quantity(1.8 10^7, 1/("Molar" "Seconds"))};
quantitiesToSolveFor(t_) = {a(t), b(t)};

Here is my function to delete units after converting to SI:

UnitStrip(exp_) := Replace(exp, a_?QuantityQ :> QuantityMagnitude(UnitConvert(a)), All)

I've tried it and found it to work as expected. Here is my call to NDSolve:

result = NDSolve(UnitStrip(Join(rateeq(t), 
                           initCond(Quantity(0, "Microseconds"))) /. 
                           rateConstValues), 
                 quantitiesToSolveFor(t), 
                 UnitStrip({t, 0, Quantity(500, "Microseconds")}))((1))

This gives me replacement rules for a (t) and b (t) as interpolation functions. I can make a version of those same results but with the units put back as follows:

UnitizedResult = (# -> (Quantity(# /. result, "Moles"/"Meters"^3) /. 
                  t -> (t/Quantity(1, "Seconds")))) & /@
                 (quantitiesToSolveFor(t))

Let's convert b (t) into a function and try a value:

f(t_) = b(t) /. UnitizedResult;
UnitConvert(f(Quantity(250, "Microseconds")), "Molar")

(* 1.65921 10^-10 M *)

And that result is correct. Here is the strange part:

Plot(Evaluate(f(t)), 
     {t, Quantity(0, "Microseconds"), Quantity(500, "Microseconds")}, 
     TargetUnits -> "Molar")

enter the description of the image here

Not only is the magnitude far apart (about 11 orders of magnitude), but the trend is wrong … it should be a decreasing function that approaches zero as an asymptote. I have verified that f (t) behaves as it should when using a manipulator:

Manipulate(UnitConvert(f(Quantity(t, "Microseconds")), "Molar"), {t, 0, 500})

enter the description of the image here

Any ideas?

Edited to add: So, if I do not do the conversion on the t axis to a unified version, everything works fine. Does anyone know why my approach to transforming the t-axis is not working here? And does someone have a way to make the conversion successfully?

c ++: Why do I get this error in VS2017 but the game compiles and works as expected?

I have this error, but the game works and that variable ActorThatOpens is assigned correctly.

enter the description of the image here

In my header the included ones are: 

#include "CoreMinimal.h"
#include "Components / ActorComponent.h"
#include "Engine / TriggerVolume.h"
#include "OpenDoor.generated.h"

As far as I can tell from the documents Components / ActorComponent.h contains the function GetWorld ().

I have to go to work now, but I've been scratching my head for about an hour, and I'll continue when I get home later. If someone can see what I am doing wrong and I can help, I will be very grateful.

(As you can probably tell, I'm completely new to C ++) THANK YOU!

numerical integration: NIntegrate generates a great value compared to what was expected

I'm trying to replicate something my teacher has done. He has done it with the MATHCAD software but I am more familiar with Mathematica. 

Rxxn[a_, b_, t_] : = (p ^ 2 (a - b)) / (Sqrt[(a - b)^2 + t^2 + p^2] ((a - b) ^ 2 + t ^ 2)) + (a - b) / Sqrt[(a - b)^2 + t^2 + p^2]  + (a - b) / Sqrt[(a - b)^2 + t^2] 
Rxxnavg[a_, t_, k_?NumericQ] : = (Rxxn[a, 0.5, t] - Rxxn[a, -0.5, t]) * Cos[k t]
Rxx[a_?NumericQ] : = NIntegrate[Rxxnavg[a, t, 0], {t, 0, [Infinity]}]Rxx[0]

I got the following error:

During the evaluation of In[23]: = NIntegrate :: ncvb: NIntegrate could not converge to the prescribed precision after 9 recursive bisections in t near {t} = {6.13224 * 10 ^ 28}. NIntegrate obtained -47117.7 and 39303.336387089155` for the integral and error estimates.

Outside[26]= -47117.7

Based on what he did, we are expected to find that Rxx[0] is close to -1. However, I get this answer. I'm not sure how to remedy this.

Magento 2.3.1 varnish and cloudlfare – pages that are not cached as expected

We have a Magento 2.3.1 store that uses CloudFlare and has Varnish enabled. If we use wget or curl to load a page, that page is cached in Varnish if we try wget or curl again on that same page.

However, if we then try that URL through a browser, the page is not cached. It is then cached after the browser's first visit, and then it remains in cache at the top-up from a browser.

We add the CF + varnish rules as indicated in
https://support.cloudflare.com/hc/en-us/articles/200169376-Can-II-use-Cloudflare-and-Varnish-together-

but that does not seem to make a difference. We are using the recommended Magento default.vcl file that is generated.

Any ideas on what could prevent a wget / curl from loading a page in the Varnish cache so that any request from a browser caches that page instead of having the Varnish re-cache the page?

Oracle global temperature table: the data is truncated, but the table remains in the database! Is this an expected behavior or configuration?

As the comments indicate, Oracle's global temporary tables work differently than some might expect. They are intended to be permanent structures. The configuration allows data to be preserved when a session is closed or deleted.

The key reason to use them is that each user can only access that user's data.

All developers can use the same table and insert / update / delete without interfering with other users.

It is not necessary to drop a GTT after using it.

Statistics – expected value / normal distribution

Can someone help me answer this question?

The soluble coffee produced by a given company must contain a percentage, X, of a special additive. The specification of the technical sector of the production delimits between 30 and 35 percent of additive. The company obtains a net profit (L), per unit sold, evaluated as follows:

        L (X) = 0.10 per unit if 30 <x <35
= 0.05 per unit if 35 <x <40
= - 0.05 per unit if 25 <x <30
= - 0.10 per unit if x takes any other value.

a) We know that X: N (33; 9) (normal distribution). Calculate the expected value of L.

b) Suppose now that the company wants to increase its expected net profit by 50%. Its objective is to achieve this objective by increasing its net profit per unit sold by complying with the specifications (30 <x <35). What should be the new net benefit?

Can I send another EE visa application? UU If I need to change the expected arrival date to EE. UU.?

Please help I had sent an application but I could not get a previous interview that would fit the expected date of arrival. I had already paid the visa fee. Can I send another application by changing the target date?

Thank you.

2010 – Update of the article "The value is not within the expected range"

If I execute each line individually, it works. But if I try to execute the script with each loop, I get:
The exception calls "Update" with "0" argument (s): "The value is not within the expected range".

Code:

    $ listItems = $ list.GetItems ($ query)
$ query.ListItemCollectionPosition = $ listItems.ListItemCollectionPosition

foreach ($ item in $ listItems)
{
# Delete items
# UpdateItems
# CancelWorkflows
$ reason = $ item["Reason"] + "- This exception was opened more than 30 days and will be closed by the administrator"
$ item["Reason"] = $ reason
$ item.Update ()
Write-Host "Added reason code - $ ($ item.ID)"
$ reason = $ null
$ count = $ count + 1
}

Do I need to update a different way?
When I break and check the variables, $ item[“Reason”] It is empty, so it makes sense that I have 0 arguments.

More information: There are some columns that are necessary. There is a possibility that one of them is empty, so the element can not be updated unless that field has a value. Can I force an update on an item even if a required field is blank?

linux – Fail2ban ban does not work as expected [DDOS]

I have this jail

## To stop the DOS attack from a remote host.
[http-get-dos]
enabled = true
port = http, https
filter = http-get-two
logpath = /usr/local/nginx/localhost-access.log
maxretry = 100
Search time = 300
bantime = 6000
action = iptables[name=HTTP, port=http, protocol=tcp]

State of the prison: http-get-dos
| - Filter
| | - Currently failed: 18
| | - Total failed: 99871
| `- List of files: /usr/local/nginx/localhost-access.log
`- Actions
| - Currently prohibited: 2
| - Total prohibited: 5
`- List of prohibited IPs: 94.60.20.166 193.112.177.8

However, after running state of fail2ban-client http-get-dos, where the IP is marked as prohibited, I still receive many incoming requests from the banned IP that will cause high CPU usage:

193.112.177.8 - [01/Jul/2019:17:48:59 +0100] "GET / companies / xxx HTTP / 1.1" 200 18935 "https://example.com/companies/xxx" "shelby / 5.0 (Windows NT 10.0; Win64; x64; rv: 67.0) Gecko / 20100101 Firefox / 67.0"
193.112.177.8 - [01/Jul/2019:17:48:59 +0100] "GET / companies / xxx HTTP / 1.1" 200 18935 "https://example.com/companies/xxx" "asdfgh / 5.0 (Windows NT 10.0; Win64; x64; rv: 67.0) Gecko / 20100101 Firefox / 67.0"
193.112.177.8 - [01/Jul/2019:17:49:00 +0100] "GET / companies / xxx HTTP / 1.1" 200 18935 "https://example.com/companies/xxx" "tigger / 5.0 (Windows NT 10.0; Win64; x64; rv: 67.0) Gecko / 20100101 Firefox / 67.0"
...

Now, if I do it:

iptables -A ENTRY -s 193.112.177.8 -j DROP

I do not see any more requests in the records of this IP. The question is, why does the ban on fail2ban not work like the previous rule?

Expected behavior when adding items to your & # 39; favorites & # 39;

Make it as painless as possible, do not request login when users are still exploring products.

Some items:

Shopping cart or wish list? Save products for later in electronic commerce

The shopping cart is not just a place to store items until the purchase: it is a comparison table, a reference, a scrapbook to get ideas. Therefore, contrary to the beliefs of modern e-commerce teams, adding an item to a shopping cart does not necessarily mean that the item has a high probability of being purchased immediately. People often use the shopping cart as a tool to help them make purchasing decisions, and the shopping cart is both a sandbox for the consideration of products and a direct means of purchase. Keep this in mind if you are following the abandonment of the shopping cart as one of your analytical metrics: an item left in the shopping cart can take you to a purchase later.

Users often want to buy only some of the contents of their cart immediately, but do not want to lose all the work that goes into finding other products of interest. Provide an easy-to-find feature to save items for later, tag it other than "wishlist" and do not block access to it with login walls.

Logon walls stop users in their tracks

As a general rule, we recommend that you use the principle of reciprocity when considering a login wall in front of your users. Always analyze what the perceived benefits are for users: if there is the slightest possibility that those benefits are not evident, leave the wall to start the session, either jointly or pressing to the point where users are convinced of the underlying logic and know exactly what to expect from your site.