bitcoind – Recover corrupted wallet due to system crashed

My server was crashed suddenly and didn’t shut down bitcoin core probably, so now my wallet was corrupted due to it didn’t be released. I try to moved the corrupted wallet to a new server but it can’t be load:

Wallet file verification failed: wallet.dat corrupt, salvage failed

I have also tried to use pywallet to rescue, but getting this error:

ERROR:root:Couldn't open wallet.dat/main. Try quitting Bitcoin and running this again.

I suspect that my wallet.dat was totally corrupt so pywallet couldn’t found main . Any help on this please ? Possible to get back my privatekey from wallet.dat please ? Thanks alot.

Information:

bitcoin version: v0.18
os: centos7

I missed my medical visit for my carte de sejour in france due to COVID-19. Can I still re-enter the country on my work visa?

I missed my medical visit for my carte de sejour in france due to COVID-19. Can I still re-enter the country on my work visa? I recieved my visa in November. My medical appointment to receive my carte de sejour was scheduled in mid March, but since all the craziness happened with COVID i returned to the US and couldn’t attend my medical appointment. Will i be allowed back into the country on my work visa, how does one go about rescheduling the medical appointment?

Will OVH/SoYouStart suspend servers on the day they are due if unpaid?


I’m currently transferring some funds to my bank to pay for two of my servers, there is not enough in there at the moment. It will be another 2-3 days until it is done, the servers are due tomorrow.

I’ve already asked them to extend the due date a few days but they said no.

Will they suspend the servers on the day that they are due, or do they give you a 1 or 2 day grace period to pay?

terminology – Navmesh awkward path generation with string pulling due to “inner” vertices

I’ve identified a problem and a possible solution related to navmesh-based pathfinding. Before diving in, I’ll preface my post with some questions to keep in mind as you read:

  • Is this a known problem that people have solved before?
  • Is there a term for the problem that could help me search for information related to it?
  • Is the solution I came up with an existing idea? If so is there a name for the algorithm or some other search term I could use to find more information?
  • Is there a better solution? If so, please point me to it.

For reference, I’m using images from http://jceipek.com/Olin-Coding-Tutorials/pathing.html#navigation-meshes and generally following the advice laid out there.

tl;dr of that blog post is

Decompose your walkable area into a navmesh, treating convex polygons as nodes and their borders as edges so that you can perform an A* search to get from point A to point B. To translate from “node ids” back to real points, use string-pulling.

Here’s a copy of the example space:
initial example area

And an example generated path after performing string pulling:
example area with a completed path from A to B

So far so good.

But I realized this approach generates an awkward path in a situation like this:
awkward path

In this situation, a trio of nodes are all adjacent to each other, and so the A* will generally choose a path directly from the starting node to the ending node, despite an intuitive understanding that the agent can move in a straight line from A to B which travels through a different polygon.

I’ve been working on a solution to this problem and so far my best idea is to apply a transformation to the nav mesh. My description of this will be a little hazy as I’m making up terminology to describe the approach…

  • Define a shared edge as a line segment that is shared by two convex polygons in the navmesh. Maybe a.k.a. a “portal” for string-pulling purposes.
  • Define an inner vertex as a vertex in the navmesh for which all attached line segments are “shared edges”. The vertex in the center of the three polygons in the image above is an inner vertex.
  • Identify an inner vertex. Follow its attached shared edges to what I’ll call neighbor vertex. (possible improvement; If the neighbor vertex is also an inner vertex, recurse to its neighbors until all of the neighbors are non-inner.)
  • Remove all shared edges from the navmesh that were traversed in the previous step, forming a new polygon whose border is defined by the neighbor vertices in the previous step. Redefine the edges accordingly (I’ll hand-wave that)
  • Repeat until no inner vertices remain.

The result of this on the example above should result in this:

Transformed navmesh

And with the same A-B path from before, the string-pulling should now result in a straight line:

Transformed navmesh with fixed path planning

I believe that as long as the navmesh has no inner vertices, all paths generated with the approach described in the linked blog post should seem “natural” and not have any surprise corners in what seems like open space.

Per my questions at the beginning of this post, I’m looking for more information, e.g. has anybody else solved this problem before, is there a better way to do it, and is there even a name/term for this problem?

Navmesh awkward path generation with string pulling due to “inner” vertices; terminology question

I’ve identified a problem and a possible solution related to navmesh-based pathfinding. Before diving in, I’ll preface my post with some questions to keep in mind as you read:

  • Is this a known problem that people have solved before?
  • Is there a term for the problem that could help me search for information related to it?
  • Is the solution I came up with an existing idea? If so is there a name for the algorithm or some other search term I could use to find more information?
  • Is there a better solution? If so, please point me to it.

For reference, I’m using images from http://jceipek.com/Olin-Coding-Tutorials/pathing.html#navigation-meshes and generally following the advice laid out there.

tl;dr of that blog post is

Decompose your walkable area into a navmesh, treating convex polygons as nodes and their borders as edges so that you can perform an A* search to get from point A to point B. To translate from “node ids” back to real points, use string-pulling.

Here’s a copy of the example space:
initial example area

And an example generated path after performing string pulling:
example area with a completed path from A to B

So far so good.

But I realized this approach generates an awkward path in a situation like this:
awkward path

In this situation, a trio of nodes are all adjacent to each other, and so the A* will generally choose a path directly from the starting node to the ending node, despite an intuitive understanding that the agent can move in a straight line from A to B which travels through a different polygon.

I’ve been working on a solution to this problem and so far my best idea is to apply a transformation to the nav mesh. My description of this will be a little hazy as I’m making up terminology to describe the approach…

  • Define a shared edge as a line segment that is shared by two convex polygons in the navmesh. Maybe a.k.a. a “portal” for string-pulling purposes.
  • Define an inner vertex as a vertex in the navmesh for which all attached line segments are “shared edges”. The vertex in the center of the three polygons in the image above is an inner vertex.
  • Identify an inner vertex. Follow its attached shared edges to what I’ll call neighbor vertex. (possible improvement; If the neighbor vertex is also an inner vertex, recurse to its neighbors until all of the neighbors are non-inner.)
  • Remove all shared edges from the navmesh that were traversed in the previous step, forming a new polygon whose border is defined by the neighbor vertices in the previous step. Redefine the edges accordingly (I’ll hand-wave that)
  • Repeat until no inner vertices remain.

The result of this on the example above should result in this:

Transformed navmesh

And with the same A-B path from before, the string-pulling should now result in a straight line:

Transformed navmesh with fixed path planning

I believe that as long as the navmesh has no inner vertices, all paths generated with the approach described in the linked blog post should seem “natural” and not have any surprise corners in what seems like open space.

Per my questions at the beginning of this post, I’m looking for more information, e.g. has anybody else solved this problem before, is there a better way to do it, and is there even a name/term for this problem?

[ Politics ] Open Question : So once again the terrorist rioters were wrong as always, George Floyd died due to drugs in system?

A combination of this and heart disease is why he passed out. 

What to do if my 90 years old mother has to go back to Peru and the country is still not safe to be there due to the covid-19 pandemia

My Peruvian 90 years old mother has a valid visa up to 2023. Her stay in ending June 19 of this year 2020.If she applies for extension of stay I-539 and the extension is denied OR if the extension of stay ia approved but ends and it is not safe to go back to Peru. What should we do? Even if a repatriation flight were available to go back to Peru. Can she apply for an humanitarian case? In other words If she has to go back to Peru when the country is still not safe. and there is nobody that can take care of her in Peru. Can she apply as an humanitarian case. Or what should we do? any ideas?

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customs and immigration – My pregnant wife with Green card status is stuck in India due to COVID-19, What are my options as she cannot come until she gives birth?

My wife is stuck in India since Feb 24, she’s supposed to come on April 30th. But, all flights were cancelled including ours. There are repatriation flights, but, she is 32.5 weeks pregnant when the repatriation flights start running from India to U.S during next phase.

I am thinking my wife will come back to U.S before August 18th (she’ll be outside for 177 days) after she gives birth at the end of July.

Can she go back to India after 2 months of staying in U.S to take care of our baby? (Meantime, my parents will be taking care of the baby). Will she face any more questions?

(I am a U.S. citizen and not worried about my kid as I can apply for CRBA)

Please be nice as we are going through a tough time staying apart like so many others.

Credit card stopped due to fraud activity, but hotel booking needs credit card for security bond

So I’ll be checking in a apartment hotel tomorrow, my company booked the hotel with the company credit card, but I realize that during check in they require a credit card for security bond. And the hotel stated on their website that no cash payment is accepted.

My card got stopped yesterday by the bank due to a suspicious fraud, and new card is still on its way via mail. So I don’t have a valid credit card to use, and they do not accept cash. So I have no idea what I need to do, called them just now but reception opens tomorrow morning, and I’m quite worried. Can they cancel my stay if I don’t have a valid credit card for the security bond? I do have a Debit MasterCard but that’s different from a credit card.

Where can we find frequently updated details about travel/entry restrictions due to Coronavirus (nCoV-19)?

Due to the outbreak of nCoV-19 (Novel Coronavirus) many Countries have imposed several entry restrictions. But these are quite confusing for a lot of people. Some countries allow transit through parts of China (like Shanghai) but some restrict transit even through Hong Kong/Macau. Philippines restricted passengers coming from Taiwan too, but I think that that was later changed.

Where can one find a list of such restrictions for all the countries, ideally a source that is updated frequently