The CRC32 found in zip and a lot of other places uses the polynomial 0x04C11DB7; its reversed form 0xEDB88320 is perhaps better known, being often found in little-endian implementations.

CRC32C uses a different polynomial (0x1EDC6F41, reversed 0x82F63B78) but otherwise the computation is the same. The results are different, naturally. This is also known as the Castagnoli CRC32 and most conspicuously found in newer Intel CPUs which can compute a full 32-bit CRC step in 3 cycles. That is the reason why the CRC32C is becoming more popular, since it allows advanced implementations that effectively process one 32-bit word per cycle despite the three-cycle latency (by processing 3 streams of data in parallel and using linear algebra to combine the results).

When I paid Apple the $99 to open my developer account, my company was not yet legally registered, so I used my name. But now my startup is a registered company and I need to have the company’s name showing as the developer. 

Does anyone know how to change the developer name? I already ready through [Transferring ownership of an iPhone app on the app store](https://stackoverflow.com/questions/671382/transferring-ownership-of-an-iphone-app-on-the-app-store) and that’s is not exactly what I am looking for: 

I&#39;m not trying transfer the account to a different company. I just want to setup somehow so that the company’s name is what is shown as the developer.

How to change my app’s developer name on Apple&#39;s App Store?

After yesterday&#39;s Windows Update, I seem to have issues building my projects.

    Related Windows Updates could be:
    ASP.NET MVC 2.0: KB2993939
    ASP.NET MVC 3.0: KB2993937
    ASP.NET MVC 4.0: KB2993928
    ASP.NET MVC 5.0: KB2992080
    ASP.NET MVC 5.1: KB2994397

![System.Web.Mvc-related errors][1]

These errors all seem to be related to the `System.Web.Mvc` namespace of which I checked; it is still being associated with the project under `References`. What could have gone wrong with my MVC project during the Windows Update, and how should I go about rectifying it?

Here is the log that indicates the updates administered today:

![16/10/2014&#39;s Windows Update][2]

  [1]: http://i.stack.imgur.com/Y69rp.png
  [2]: http://i.stack.imgur.com/QLgwv.png

System.Web.Mvc not functioning as expected after Windows Update

What is the difference of CRC32 and CRC32C? I know CRC32 for a long time, but just heard CRC32C today. Are they basically the same method (i.e. both results in the same hash for a given data)?

CRC32 vs CRC32C?

<p>What is the difference of CRC32 and CRC32C? I know CRC32 for a long time, but just heard CRC32C today. Are they basically the same method (i.e. both results in the same hash for a given data)?</p>


I am not able to understand what Range / primary key is here in the docs on [Working with Tables and Data in DynamoDB][1]

How does it work?

What do they mean by &quot;unordered hash index on the hash attribute and a sorted range index on the range attribute&quot;?

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html

What is Hash and Range Primary Key?

I&#39;ve implemented a BloomFilter in python 3.3, and got different results every session. Drilling down this weird behavior got me to the internal hash() function - it returns different hash values for the same string every session.

Example:

    &gt;&gt;&gt; hash(&quot;235&quot;)
    -310569535015251310

----- opening a new python console -----

    &gt;&gt;&gt; hash(&quot;235&quot;)
    -1900164331622581997

Why is this happening?
Why is this useful?


hash function in Python 3.3 returns different results between sessions

Ruby 2.3 introduces a new method on `Array` and `Hash` called `dig`. The examples I&#39;ve seen in blog posts about the new release are contrived and convoluted:

    # Hash#dig
    user = {
      user: {
        address: {
          street1: &#39;123 Main street&#39;
        }
      }
    }

    user.dig(:user, :address, :street1) # =&gt; &#39;123 Main street&#39;

    # Array#dig
    results = [[[1, 2, 3]]]
    results.dig(0, 0, 0) # =&gt; 1

I&#39;m not using triple-nested flat arrays. What&#39;s a realistic example of how this would be useful?

**UPDATE**

It turns out these methods solve one of the most commonly-asked Ruby questions. The questions below have something like 20 duplicates, all of which are solved by using `dig`:

https://stackoverflow.com/questions/4371716/how-to-avoid-nomethoderror-for-missing-elements-in-nested-hashes-without-repeat

https://stackoverflow.com/questions/1820451/ruby-style-how-to-check-whether-a-nested-hash-element-exists

How do I use Array#dig and Hash#dig introduced in Ruby 2.3?

I&#39;ve noticed the table of the time complexity of set operations on the python official website. But i just wanna ask what&#39;s the time complexity of converting a list to a set, for instance,

    l = [1, 2, 3, 4, 5]
    s = set(l)

I kind of know that this is actually a hash table, but how exactly does it work? Is it O(n) then?

What is time complexity of a list to set conversion?

I&#39;m writing a tool in C# to find duplicate images. Currently I create an MD5 checksum of the files and compare those. 

Unfortunately, the images can be:

- Rotated by 90 degrees.
- Have different dimensions (smaller image with same content).
- Have different compression or file types (e.g. jpeg artifacts, see below).

[![higher resolution koala][1]][1][![lower resolution koala][2]][2]

What would be the best approach to solve this problem?

  [1]: http://i.stack.imgur.com/UvKaV.jpg
  [2]: http://i.stack.imgur.com/8lplJ.jpg

Algorithm to compare two images in C#

We&#39;re using Liquibase 3.2 with Java 6.  Is there a way I can force Liquibase to recalculate checksums without re-running the same statements from our Liquibase files?  In our database, I run this ...

    update DATABASECHANGELOG set md5sum = null where 1;

However, when I run my Liquibase change scripts, certain executions still fail with the following errors ...


	invoking liquibase change script with file /tmp/deploywork/db.changelog-master.xml
	running /usr/java/liquibase/liquibase  --logLevel=info --driver=com.mysql.jdbc.Driver --classpath=/usr/java/jboss/modules/com/mysql/main/mysql-connector-java-5.1.22-bin.jar --changeLogFile=/tmp/deploywork/db.changelog-master.xml --url=&quot;jdbc:mysql://myservername:3306/my_db&quot; --username=username --password=password update 
	INFO 5/13/15 2:15 PM: liquibase: Successfully acquired change log lock
	INFO 5/13/15 2:15 PM: liquibase: Reading from my_db.DATABASECHANGELOG
	INFO 5/13/15 2:15 PM: liquibase: Successfully released change log lock
	Unexpected error running Liquibase: Validation Failed:
	     3 change sets check sum
	          db.changelog-1.0.xml::1357593229391-25::rob (generated) is now: 7:5cfe9ecd779a71b6287ef2360a6979bf
	          db.changelog-7.0.xml::create-address-email-index::davea is now: 7:da0132e30ebd6a1bc52d9a39bb8c56d7
	          db.changelog-7.0.xml::add-myproject-event-object-id-col::davea is now: 7:2eab5d784647ce33ef3488aa8c383443
	
	
	SEVERE 5/13/15 2:15 PM: liquibase: Validation Failed:
	     3 change sets check sum
	          db.changelog-1.0.xml::1357593229391-25::rob (generated) is now: 7:5cfe9ecd779a71b6287ef2360a6979bf
	          db.changelog-7.0.xml::create-address-email-index::davea is now: 7:da0132e30ebd6a1bc52d9a39bb8c56d7
	          db.changelog-7.0.xml::add-myproject-event-object-id-col::davea is now: 7:2eab5d784647ce33ef3488aa8c383443
	
	liquibase.exception.ValidationFailedException: Validation Failed:
	     3 change sets check sum
	          db.changelog-1.0.xml::1357593229391-25::rob (generated) is now: 7:5cfe9ecd779a71b6287ef2360a6979bf
	          db.changelog-7.0.xml::create-address-email-index::davea is now: 7:da0132e30ebd6a1bc52d9a39bb8c56d7
	          db.changelog-7.0.xml::add-myproject-event-object-id-col::davea is now: 7:2eab5d784647ce33ef3488aa8c383443
	
		at liquibase.changelog.DatabaseChangeLog.validate(DatabaseChangeLog.java:181)
		at liquibase.Liquibase.update(Liquibase.java:191)
		at liquibase.Liquibase.update(Liquibase.java:174)
		at liquibase.integration.commandline.Main.doMigration(Main.java:997)
		at liquibase.integration.commandline.Main.run(Main.java:170)
		at liquibase.integration.commandline.Main.main(Main.java:89)


Here is one of the change sets that the script is complaining about …

	    &lt;changeSet author=&quot;davea&quot; id=&quot;add-myproject-event-object-id-col&quot;&gt;
	    	&lt;addColumn tableName=&quot;sb_myproject_event&quot;&gt;
	            &lt;column name=&quot;OBJECT_ID&quot; type=&quot;VARCHAR(32)&quot;/&gt;
	        &lt;/addColumn&gt;
	        &lt;createIndex indexName=&quot;SB_myproject_EVENT_IDX&quot;
	            tableName=&quot;sb_myproject_event&quot;
	            unique=&quot;false&quot;&gt;
	            &lt;column name=&quot;OBJECT_ID&quot; type=&quot;varchar(32)&quot; /&gt;
	    	&lt;/createIndex&gt;
	    	&lt;sql&gt;update sb_myproject_event set object_id=LEFT(SUBSTRING_INDEX(event_data, &#39;&amp;quot;id&amp;quot;:&amp;quot;&#39;, -2), 24) where object_id is null and event_data is not null;&lt;/sql&gt;
	    	&lt;!--  Delete older events that no longer need to be processed --&gt;
	    	&lt;sql&gt;delete from sb_myproject_event where id not in (select q.* from (select e.id FROM sb_myproject_event e, (select object_id, max(date_processed) d from sb_myproject_event group by object_id) o where e.object_id = o.object_id and e.date_processed = o.d) q);&lt;/sql&gt;
	    &lt;/changeSet&gt;

As I said, I only want to recalculate checksums (have to do this because we&#39;re changing Liquibase versions).

Content Type	Original Author	Original Content on Stackoverflow
Question	Wirawan Purwanto	View Question on Stackoverflow
Solution 1 - Hash	DarthGizka	View Answer on Stackoverflow

CRC32 vs CRC32C?

Hash Problem Overview

Hash Solutions

Solution 1 - Hash

System.Web.Mvc not functioning as expected after Windows Update

How to change my app’s developer name on Apple's App Store?

Attributions