@silicon valley code camp

Sessions are a little lightweight,  but not bad.

Samsung Hackathon

This past Weekend I attended a Hackathon, my first, presented by Samsung, over at the PayPal Campus in San Jose.  It had a variety of sponsors, including Immersion Haptics and PayPal.

The website was on http://hackathons.splashthat.com/


I thought I would comment on what I thought done right, and what could have been improved in my opinion.

First of all, it was a large and successful event, where 21 teams presented.

They fed us 4 meals over two days, and had snacks, candy, and drinks to boot.  The food was plentiful, and there were vegetarian options, which was nice. There was plenty of food, and they didn't clear left overs away immediately, so I had a slice of pizza from lunch at 3 am, and mexican food from dinner after breakfast.

There was also keg of beer those over 21 could get a drink from with dinner.  I don't know what type of beer, but it was tasty.

They opened up a bunch of rooms on two floors for our use in the building.
In fact, the staff, both the PayPal employees and the event staff were wonderful and welcoming.  There were volunteers there, including one guy, I believe from Holland, who stayed the whole night and kept going.  People from the company who were helping with the API stayed until 8, and were there in the morning.

There were people there willing to help with the APIs, (but see below).

They gave us phones to work on, in exchange for Driver licenses, and later, credit cards (no charge), so that we could keep the devices over night.  This helped a lot, especially with the Chord API, since it is Samsung specific.

There were however a few things that I thought could have gone better.  They didn't prevent me from enjoying the Hackathon, but I think the sponsors could have gotten more engagement from us with a few small changes.

API issues, Rooms and Prizes

First of all, a large focus of the Hackathon was on the Samsung Chord API.  The Chord API didn't work over the PayPal wifi network.  That should have been tested to begin with, fixed if possible, or more widely announced otherwise.  We were able to get it working over wifi direct, but we could have been told to do that.

The Chord API was hard to use in projects in Eclipse, and the Technical Evangelist suggested to multiple people that they base their project on the sample code for the chord demo, instead of showing how to include it.  We ended up having to do that to get it working, and having to create a new repository to do so.

They also said that there were issues with the Emulator... this was true, since even on a separate wifi AP, we could only get the emulator to receive, not send.

The Chord API seemingly worked differently on different devices.  Our app would crash the Note Phablet we were given, but not other phones.  We also had issues with the same xml rendering certain items on one phone, and not on another, crashing depending on the order of devices, and updates triggered by Chord messages only running on one device.

Given that all the Phones were Samsung devices, this suggests app development across devices may require a lot of testing for idiosyncratic differences.  Given the short timeline of the Hackathon, and our lack of experience with Android we were unable to fix several device specific issues before final submission, which effected the appearance of our final work.

The Immersion Haptic API was fairly easy to use in Eclipse.  That said, there were no instructions for including it in the Android Studio beta, so we ended up switching to Eclipse from that.  I did talk to someone passing out Immersion swag later in the day (see below) and mentioned this, and they said they would find out if there were Android Studio instructions in the pipeline, but I never saw them again, even when I went looking.

Not a huge thing, and understandable, but something they may want to look at in the future, when Android Studio and it's build system become the default for new developers and official documentation.

Also, I believe the Immersion Haptic API License requires you to mention them.  It would have been nice if sample code/xml for this had been provided for the many teams who were new to Android.

They opened up rooms, which was good because there was a lot of crowding to start with, and the initial room had speakers playing music which a few of us found distracting.  We were able to spread out, move furniture around, and nobody got upset with us.  It's hard to find a room that will hold 700 + people, but I think they could have used video conferencing equipment in the rooms so that people didn't have to crowd into the initial room for announcements.  Alternatively, they could have removed the tables and chairs to fit more people, and split us up for development.

PayPal wanted people to try their APIs, and a few teams did, (including the overall winner, Split, who had an awesome check splitting app).
However, the prizes were all for the Chord API or Immersion Haptics API.  I think PayPal would have gotten more engagement if the prizes had mentioned using their API, or they had sponsored a prize themselves.  Unfair, given all they did for us, but developers are going to focus on what the Hackathon instructions say, and the PayPal API wasn't mentioned until the opening announcements.

I didn't attempt to use it, so I am not sure that there were people from PayPal to help, but I think so.  I did glance at the documentation, and it was very nice.

Swag

Swag, IMHO should promote the company to interested parties.    

Some swag like T-Shirts for the Hackathon and from Immersion was given out to people who came early.  But many people left after the first few hours meaning that the swag went to people who didn't necessarily engage with the Hackathon beyond showing up.

PayPal dumped a box of old swag on a table near the beginning of the day (10 am maybe?), and it went quickly.  I did get a sweet multitool.  But that could have been saved for people who engaged with the Hackathon, or even used as a Prize.

Immersion did give out cards with usb drives and copies of their software later in the day after many people had left.  That was the right thing to do, waiting.

I would note that at least one team demoed an app for using the Chord API to notify friends about swag.

Final Thoughts

I personally had a great time. I learned a lot about Android development, quick prototyping, git, etc.

You can see our project on https://github.com/bdettmer/RockPaperMonsterHack

I am interesting in using all three API's in the future. I appreciated the effort it takes to run a Hackathon, and the cost.  I only mention the above in the hope that
future Hackathons can be more productive for the companies.

#samsung #samsunghackathon #immersion #paypal

When I fell in love with Computer Programming

• When I was 8 or 9, I had an MS DOS computer.  The monitor was color, and it has QBASIC on it, and I had a book of QBASIC programs.  I remember writing programs that would generate circles, with a random color, size, and location on the screen. I would also generate sounds, beeps really, in time with the circles.  I didn't know about command line arguments, so every change I made I would do by changing the code itself.  The numbers were all numeric literals.  I got it running so fast that the filling of the circles couldn't keep up with their drawing. I liked making it go, and controlling it, and making music and shapes.
• When I was 13 or, we got a A dialup 28.8k modem, and a Windows  Computer from Gateway.   There was no built in programming language, but I liked chatting online, and eventually started using Mirc and writing a few scripts. There may be an archive of one or two somewhere, because I posted a few to some websites, back in the day.  I learned about variables and conditionals.  I liked getting the program to do what I wanted, and not having to type things repeatedly.  
• I'm and about to graduate with a Bachelors Degree in Psychology.  I had a great statistics professor, Jack Vevea, who has us do our classes using R.  I did well, and I and another undergrad were invited to one of his graduate level courses in item response theory.    We have a program where we had to calculate a value on 2400 elements.  Each element took about 6 minutes with the program we were given, because it tries to calculate a value to a high degree of accuracy. That's 10 days of non-stop running. I look at the code and figure out how to narrow the search down at each iteration so it runs more quickly.  
• I'm back in school, and  I am learning C and Java.  I take the data structures and Java for C programmers classes at the same time I take the prerequisite course, work really hard and get an A in all of them.  I like learning, and working hard, and figuring things out.  
• I find out about the tutor program.  I join it, and and am made a mentor and senior tutor within the first week, on the basis of my work.  I find out that I love helping people learn about programming, and that having to explain stuff makes me comprehend it better.
• I am looking through job postings for internships using my browser's find in page function, and realize I can write something to automate this for me.  I write the first version of Gutsy, in Perl.  I like being able to take what I know and use it in real everyday life.  

I fell in love multiple times with programming.  It wasn't a linear progression, where I learned to code a little when I was young.  I had to come back to it, again and again, learning new things each time.  

quick vim trick for fixing indentation and returning to where you were

So, many people have noted that you can use gg=G to fix indentation in a file.

gg makes the program go to the top of the file, and =G idents until the bottom.   however this places your cursor at the first line in the file, which isn't something you probably wanted to do when you just wanted to fix indentation.

But you can use 2<C-o> to go back to the place you typed the command. <C-o> jumps back, but you need two jumps backward to get back to where you were.

Therefore I've placed nmap <leader>g gg=G2<C-o> in my .vimrc to fix indentation as needed without needed to go back to where you were.

vim macro: c declaration to c definition outline

There is probably a prettier way to do this, but I've made my "d register the following macro

yy0Gi^Mp<80>kb^[pA<80>kb {^M^M}^M^M^[^O<80>kd

this will copy a c declaration, move it to the bottom of the file, replace the ; with an opening curling brace and insert a closing curly brace a few spaces down, before going back to the initial declaration and moving down.  This lets you use a range

so 10@d will do this with 10 declarations as long as they don't have spaces.

pretty useful for me.

recursivereverse
================

Example is here: https://github.com/gryftir/recursivereverse

recursively reverse a linked list.  Recursion is mostly used to keep track of state data (in this case, node information and order) using the stack's function call order.

AFAIK there isn't anything you can do with recursion you can't do with an interative approach, but the data structures are going to be somewhat ugly.

Recursion isn't hard, it's just not taught correctly.  It's fairly easy to break it down into rules.

And then people memorize how to do stuff, instead of learning it from priniciples.

Take the classic question, recursively reverse a linked list.

You will see a lot of people making false starts, or trying to reverse the list in some way like they would reverse an array, or even repeatedly walking the list to the end.

But if you understand some simple rules about recursion, it's fairly easy to figure out how to do this on the fly.  And that is so much better then memorization, because you can explain why you are doing things.

first you are reversing, so you're moving backward, which means you calls your function, then do assignments.  If you were doing something moving forwards, like printing in order, you'd print first, then call the function.

Now we need to worry about the end, and the beginning.

First, the beginning, which happens after we have recursively walked the list.

Now, we want to walk to the last node before null, and we need a place to store what we return.  so assuming we have something like this in c  'node * recursivereverse(node * current)' and a node structure with next as the next link (we never touch our data)

our test is
if (current->next)
  node * newbeginning = recursivereverse(current->next);
else
  return current;
//some assignments go here;

return newbeginning;

Then we just need to figure out the assignments.

Now, people may get tripped up and try to use the new beginning... but then they have to walk it to the end... but the current node already knows the node that comes after it.

so we assign current->next->next = current;  IE the node that was previously after the current node now points to the current node as it's next.
And that's fine for all the rest of the list, until we get to our original beginning node.  We need to worry about the new end.

Since it's going to the end, we need to point it to NULL, otherwise it will point to it's predecessor, meaning we'll have an infinite loop at the end of the last two nodes.

Easy way to deal with it is to just assign the next of the current node to NULL, for each node.


so we add to current->next->next = current;
current->next = NULL;

and then you have a reversed linked list.  This makes certain assumptions about the list (like it has at least one node, and isn't circular), so don't just copy this for your interview.

So with some simple rules, I figured out how to reverse a linked list.  But those simple rules aren't taught, or at least, I came up with them for myself after I became a computer science tutor at my college, because I needed people to understand recursion.

So I guess my point is, it's not that people can or can't understand recursion, it's whether they are taught to think about things in the right way.

Now to a certain extent, we need to teach people to generalize, but if you teach people a general rule (always worry about the beginning and end of any data structure, and that's important for everything, including memory management and debugging) and a recursion specific rule (call the function first to reverse, call the function after to use the current order), and they can generalize.

Too often people come to program with the ability to copy code and get it working (and that isn't anything to denigrate, because it's not simple), but lack the understanding of how to think about things.

More Vim stuff, fix indentation and and remove blank lines

I've been using Vim as my ide, and it's been wonderful.

some additional cool things I've found.

you can have your whole file's indentation fixed with gg=G
it may be helpful to :set sw= and :set tabstop= to 4 or 2, and turn cindent on :set cindent, to handle brackets.

gg goes to the top of the file = fixes indentation, and GG does the same to the bottom of the file

you can erase blank lines with :g/^$/d

:g makes it a global command executed on all instances which match your search pattern, ^$ (start of line and end of line with nothing in between) matches blank lines, and d deletes

you might also use something like :g/^\s*$/d to remove all lines with either blanks or only whitespace

for Perl, I recently used :%s/\(\S\+\)\s*\(#.*\)/\r\U\2/g which cuts any comments from the end of a line and inserts them on a new line, in uppercase and :%s/\s*\(#.*\)/U\1/g which removes any spaces between a comment and the beginning of the line and makes the comment uppercase to be useful.

new VIM version autocomment fix

I compiled the most recent version of VIM.  It has an annoying behavior

if I start a comment in insert mode and press enter in insert mode, the next line is automatically a comment too.

This means cutting and pasting from outside vim will fail at the first comment.  I guess it's useful for long comments, but mostly it's an annoyance.

However, by piecing together stuff from a few web pages and vim doc you can easily fix this.

You need to change your format options

you can do this from inside vim with set formatoptions. you can see your current formatoptions with :setlocal

So briefly:

To turn off, you need to disable the q option in formatoptions 
:setlocal find your format options then in your .vimrc au FileType * set formatoptions= after the =, put your format options without the q 
see http://vimdoc.sourceforge.net/htmldoc/change.html#format-comments for more details


* after FileType can be a language... so c, perl, ruby, python, etc.  

Thanks to http://www.kevinslonka.com/index.php?section=1&blog=179&page=1 for getting me started.  The comments have several clever fixes, including a compromise to stop commenting if the commented line ends with a space, but I haven't gotten that working myself.  You can also fix just the pasting with :set paste, if you prefer.

Too much time in the terminal

I just tried to use Ctrl-A to go to the beginning of the line in chrome :)

The Juncture Design Pattern

It's 2 am, but if I don't write this now, I probably won't get to it with the same verve.

Lets imagine we are building an object oriented software system to handle everything a school does.  Students register for a class section.

a one to one relationship.  One college, one president.

many to one.  One teacher, several classes.  Store information about the relationship in the class info.

Now a student can be in several sections, and each section will have multiple students.

many to many relationship.

You can use callbacks, so that the section has a pointer to the student, and the student has a pointer to the section.  But what about information regarding the relationship between the two?  The grade they are getting?

That information deserves it's own object. In the middle, with two many to one relationships.

Or something.  In this example, it's not clear why.  Need to Look up the gang of 4.

Introduction

Hello Folks:

Welcome to my little blog about coding, technical job searches, anything related I think is appropriate.

My name is Lawrence Siebert.  I am a software developer.  I code.  Constantly.

You could call that a recent thing, since I've only been formally programming for about a year, or you could say I've been programming all my life.  Before I ever wrote a line in C, I was writing programs for SAS and R to do statistical analysis when I was getting my Psych degree.  I wrote scripts for the mIRC irc client on windows when I was 13.  I wrote tiny little qbasic programs on a 386 when I was 8.

So that's who I am and what I do.