I recently received an email from a recruiter for Simplion, a company headquartered in Milpitas.
I am based in San Francisco, and I'm looking only in the SF Bay Area, so I'm not that enthused with an email with the title:
"Full Stack Developer @ Richfield, MN -- Need only Local candidate for F2F Interview - F2F is must".
Now, nothing about the actual technical requirements was exactly wrong, but it was broadly generic, with no name for the company given. Clearly the company is looking far and wide, and I wish them luck, but obviously the company is searching posted resumes for key words and just spamming people. The fact that I can't look up the company suggests that the recruiter wanted to keep it a secret, which is, needless to say, annoying.
Of course given that they quoted the customer requirements, a simple search with the requirements quoted and with the location gave me the company, which I'm going to be contacting, just to tell them that their recruiter is painfully bad.
As well, the email's grammar was bad, and it's language, other then the customer requirements, are stilted. Given that it had all the hallmarks of an autogenerated email where I was profoundly the wrong person, and had an opt out link for future emails, I clicked it.
When I clicked the link, it failed to load, telling me the site can't be reached.
An email I can't opt out of means future emails are unsolicited, and thus spam. Nobody wants a recruiter to spam them.
If you are planning on using Simplion, you should definitely reconsider.
And if you are looking for a back end focused developer with experience on a variety of stacks to work in the SF Bay Area, email me.
Wednesday, August 2, 2017
Tuesday, May 16, 2017
Fixing Capslock to Be Esc on shortpress and Ctrl when held on Mac Os X Sierra
To do this, you need to install a modified version of Karabiner-Elements and edit the profile in ~/.config/karabiner/karabiner.json
Full instructions: https://github.com/tekezo/Karabiner-Elements/issues/8#issuecomment-279196849
Full instructions: https://github.com/tekezo/Karabiner-Elements/issues/8#issuecomment-279196849
Wednesday, September 16, 2015
Clocking in
Today the tech world has been abuzz with the story of Ahmed Mohamed who has arrested for bringing a clock to school, and still hasn't gotten it back from police.
Whether it's racism, anti-Muslim sentient, or just the drive to criminalize and punish innocent behavior in the name of safety, the general consensus, at least among non conservatives, seems to be that reaction to him by his school and the police was way way out of line.
Mark Zuckerberg and Obama, as well as a host of luminaries and companies involved science and tech have reached out to show support for the boy. And that's good, and to be applauded.
But we in Tech are reacting to what feels like an egregious violation, and ignoring the fact that this is an issue that goes beyond one kid in Irving, Texas's experience. We have a job beyond just being nice to one kid.
First, while the specifics of this issue will likely be called into question, we have to acknowledge that children of color face harsher discipline in general, even for the same infractions. Not just high schoolers, even preschool black children face harsher punishment. This is in part because of increases in zero tolerance policies that have lead to even minor offenses leading to suspension, expulsion, or event arrest over minor offenses like truancy or smoking.
So first of all, discipline is unfair. However, second, tolerance is now a bad thing. I'm not sure what the argument is that says kicking out a kid for misbehaving teaches them to behave better. And doing it for minor actions seems ludicrous to me.
Many of us in tech and science grew up privileged. One of those privileges was likely that if we did something cool at home, we felt safe showing our teachers and mentors. If we did something problematic, our intentions, whether to cause harm or not, were considered. Now, that privilege likely wouldn't have been afforded to people of color... but the solution is not a broken system where we take that privilege away... we need schools and communities where we extend the privilege to tinker, to make, to receive the benefit of the doubt to everyone. Great minds that could be inventing better futures don't get the education they deserve, and everyone loses. But even if it's just a normal kid that doesn't get their education... someone that could work a job and be a good citizen might instead end up in prison.
It's not enough to do things for Mohamed. We need to do things to make life better, proactively, for young people who want to learn, bright or not. We should talk to PTA meetings and neighborhood groups about the freedom to make and tinker. We should write to our legislators and local politicians. Not that we have to do everything, but we should try to do something.
Like I said, we have a job. We want to disrupt things, make the world a better place, we need to think not just about server processes and operating systems, but about justice processes and school systems.
Whether it's racism, anti-Muslim sentient, or just the drive to criminalize and punish innocent behavior in the name of safety, the general consensus, at least among non conservatives, seems to be that reaction to him by his school and the police was way way out of line.
Mark Zuckerberg and Obama, as well as a host of luminaries and companies involved science and tech have reached out to show support for the boy. And that's good, and to be applauded.
But we in Tech are reacting to what feels like an egregious violation, and ignoring the fact that this is an issue that goes beyond one kid in Irving, Texas's experience. We have a job beyond just being nice to one kid.
First, while the specifics of this issue will likely be called into question, we have to acknowledge that children of color face harsher discipline in general, even for the same infractions. Not just high schoolers, even preschool black children face harsher punishment. This is in part because of increases in zero tolerance policies that have lead to even minor offenses leading to suspension, expulsion, or event arrest over minor offenses like truancy or smoking.
So first of all, discipline is unfair. However, second, tolerance is now a bad thing. I'm not sure what the argument is that says kicking out a kid for misbehaving teaches them to behave better. And doing it for minor actions seems ludicrous to me.
Many of us in tech and science grew up privileged. One of those privileges was likely that if we did something cool at home, we felt safe showing our teachers and mentors. If we did something problematic, our intentions, whether to cause harm or not, were considered. Now, that privilege likely wouldn't have been afforded to people of color... but the solution is not a broken system where we take that privilege away... we need schools and communities where we extend the privilege to tinker, to make, to receive the benefit of the doubt to everyone. Great minds that could be inventing better futures don't get the education they deserve, and everyone loses. But even if it's just a normal kid that doesn't get their education... someone that could work a job and be a good citizen might instead end up in prison.
It's not enough to do things for Mohamed. We need to do things to make life better, proactively, for young people who want to learn, bright or not. We should talk to PTA meetings and neighborhood groups about the freedom to make and tinker. We should write to our legislators and local politicians. Not that we have to do everything, but we should try to do something.
Like I said, we have a job. We want to disrupt things, make the world a better place, we need to think not just about server processes and operating systems, but about justice processes and school systems.
Thursday, August 13, 2015
Fisher-Yates Shuffle, Reservoir Sampling, and Random permutations of N
I recently had a conversation with someone who introduced me to the concept of Reservoir Sampling, which is a technique of generation for a combination of k randomly selected elements when there are N elements total, where N is unknown or larger then available memory, and you must select elements without replacement.
Here's a version I just wrote:
That would look like:
That said, with reservoir, you won't have a random permutation of the elements. And shuffle uses extra memory if the length of the card pile is very long, and you only need some k cards.
Thus:
import random
arr = []
current = 0
while (current < return_count):
rand = random.randint(0, current)
if current < return_count:
arr.append(arr[rand])
arr[rand] = iterator.next()
current += 1
for item in iterator:
if rand <= return_count:
arr[rand] = item
current += 1
return arr
Here's a version I just wrote:
import random
"""
iterator is an Iterator/Generator object for a streamand N >= k
"""
def reservoir(iterator, return_count): arr = [] current = 0 for item in iterator: if current < return_count: arr.append(item) else: rand = random.randint(0, current) if rand <= return_count: arr[rand] = item current += 1 return arr
That would look like:
import random
def shuffle(cards): deck = [] current = 0 for card in cards: rand = random.randint(0, current) if rand != current: deck.append(deck[rand]) deck[rand] = card return deckThat said, with reservoir, you won't have a random permutation of the elements. And shuffle uses extra memory if the length of the card pile is very long, and you only need some k cards.
Thus:
import random
def resshuffle(iterator, return_count):arr = []
current = 0
while (current < return_count):
rand = random.randint(0, current)
if current < return_count:
arr.append(arr[rand])
arr[rand] = iterator.next()
current += 1
for item in iterator:
if rand <= return_count:
arr[rand] = item
current += 1
return arr
Sunday, February 8, 2015
Nurse Scheduling Problem and Optimization
I had an interview on Friday, and one of the questions has been on my mind, because I didn't really like how vague my answer was. It was presented as a design problem, but really it's a software engineering problem. And it's a problem that I might be working on, if hired.
It turns out that it's something of an instance of the Nurse Scheduling Problem. Nurses need to work a certain number of shifts, shouldn't have back to back shifts, should work about equally each week, then you have to consider different skill levels, shift preferences etc.
This isn't the exact question, of course... I'm not getting hired at a hospital. But considering I've been scheduling a lot of interviews, it strikes me that having software engineers do technical interviews of candidates is something of the same problem. Less busy, but still, a structure lots of people in tech can understand.
It's easy to think of additional constraints, either hard constraints which if violated make a schedule invalid, and soft constraints which can be used to rate valid solutions. Maybe you have an open office, and two people shouldn't interview simultaneously if they work next to each other. Soft constraint. Some people can interview for front end, some for back end, some for mobile, some for embedded, some for multiple. Maybe you have all of those at your company, and need to assign individuals to particular candidates. You may not give a good interview if you assign the embedded guy to interview someone to see if they actually know android development. Hard Constraint.
Let's say we have d developers who can interview, i individuals interviewing, and t time slots that a candidate says they are available and lets say we want to organize based on week.
Even with just d and i and the hard constraints, the naive solution will be in polynomial time. Now finding the optimal solution, with the soft constraints, the time slot issue... this is the nurse scheduling problem, and it's NP hard.
Imagine you are a manager assigning people, that's a lot of things to keep track of. Add in sick days, projects that are priorities, and a manual system is going to be pretty stressful and complicated.
So obviously I'm not looking for an optimal solution. But I've been thinking on heuristics that might be helpful.
Time slots where only one person is scheduled are easier to sub for.
Everyone may be equal, but multiple certifications can sub for more people, and can interview more people.
It strikes me that there are a variety of ways to simplify the problem. So I'll try to solve the general problem programmatically and handle corner cases in an adhoc manner.
list available time slots in a calendar. Have the the Candidates pick one time slot to commit to, then reschedule if needed. If a time slot overlaps, have a rough indication of interviewers available. Green for multiple interviewers, red for 1, disabled for 0.
Limit time slots. A morning slot and an afternoon slot. If none of the time slots work, the candidate can inform the company of when they are available by emailing.
Keep track of how many interviews a person does in a week, and when randomly selecting individuals, prefer selecting people who have done less.
I don't need to have an optimal solution, just a reasonably good one that makes finding workable solutions easier. And it's okay that I didn't have perfect answers. I don't need to design a perfect system, just one better then what they have currently. Optimization isn't always about finding the optimum way to do things. As long as you can make something better, you have improved it.
It turns out that it's something of an instance of the Nurse Scheduling Problem. Nurses need to work a certain number of shifts, shouldn't have back to back shifts, should work about equally each week, then you have to consider different skill levels, shift preferences etc.
This isn't the exact question, of course... I'm not getting hired at a hospital. But considering I've been scheduling a lot of interviews, it strikes me that having software engineers do technical interviews of candidates is something of the same problem. Less busy, but still, a structure lots of people in tech can understand.
It's easy to think of additional constraints, either hard constraints which if violated make a schedule invalid, and soft constraints which can be used to rate valid solutions. Maybe you have an open office, and two people shouldn't interview simultaneously if they work next to each other. Soft constraint. Some people can interview for front end, some for back end, some for mobile, some for embedded, some for multiple. Maybe you have all of those at your company, and need to assign individuals to particular candidates. You may not give a good interview if you assign the embedded guy to interview someone to see if they actually know android development. Hard Constraint.
Let's say we have d developers who can interview, i individuals interviewing, and t time slots that a candidate says they are available and lets say we want to organize based on week.
Even with just d and i and the hard constraints, the naive solution will be in polynomial time. Now finding the optimal solution, with the soft constraints, the time slot issue... this is the nurse scheduling problem, and it's NP hard.
Imagine you are a manager assigning people, that's a lot of things to keep track of. Add in sick days, projects that are priorities, and a manual system is going to be pretty stressful and complicated.
So obviously I'm not looking for an optimal solution. But I've been thinking on heuristics that might be helpful.
Time slots where only one person is scheduled are easier to sub for.
Everyone may be equal, but multiple certifications can sub for more people, and can interview more people.
It strikes me that there are a variety of ways to simplify the problem. So I'll try to solve the general problem programmatically and handle corner cases in an adhoc manner.
list available time slots in a calendar. Have the the Candidates pick one time slot to commit to, then reschedule if needed. If a time slot overlaps, have a rough indication of interviewers available. Green for multiple interviewers, red for 1, disabled for 0.
Limit time slots. A morning slot and an afternoon slot. If none of the time slots work, the candidate can inform the company of when they are available by emailing.
Keep track of how many interviews a person does in a week, and when randomly selecting individuals, prefer selecting people who have done less.
I don't need to have an optimal solution, just a reasonably good one that makes finding workable solutions easier. And it's okay that I didn't have perfect answers. I don't need to design a perfect system, just one better then what they have currently. Optimization isn't always about finding the optimum way to do things. As long as you can make something better, you have improved it.
Friday, December 5, 2014
A work flow for setting up front end development professionally on ubuntu
Introduction
I noticed that there wasn't a really good step by step guide for setting yourself up professionally to develop a web app from step 1 on Ubuntu. I'm a vim user, and setting vim up for javascript is a whole other post or two, but this should be editor agnostic. I don't know if this is perfect, for example I will probably add a test runner and test framework.Suggestions for things to add, especially test setup, are welcome.
- Karma and Jasmine for unit testing?
- Protractor and Selenium Web Driver for End to end testing?
Summary of steps
- Install Requirements to build nvm and git
- Install nvm
- Make your .bash_profile source nvm and install the stable version of nodejs
- Make your .bash_profile run nvm use stable
- Use npm to install yo, grunt-cli, and bower
- Run yo and install angular generator
- Run yo angular to generate angular
- Use grunt serve to display an example front page
- Use yo to add angular directives, controllers etc.
- Develop your app
1 Install Requirements to build nvm and git
We are installing nvm so we don't have a local version of node and don't have to constantly invoke sudo to install stuff with npm.First we install requirements to build nvm as well as download it:
sudo apt-get install build-essential libssl-dev curl git-core2 Install nvm
You can use the very insecure and easy to hijack:curl https://raw.githubusercontent.com/creationix/nvm/v0.20.0/install.sh | bashChoose the Manual Install:
git clone https://github.com/creationix/nvm.git ~/.nvm && cd ~/.nvm && git checkout `git describe --abbrev=0 --tags`3 Make your .bash_profile source nvm and install the stable version of nodejs
add the following to your .bash_profileexport NVM_DIR="/home/lawrence/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh" # This loads nvm
NVM_SYMLINK_CURRENT="true"run the following to install the latest stable version of node.
nvm install stable4 Make your .bash_profile run nvm use stable
Add the following to the bottom of your .bash_profile to have node always runningnvm use stable > /dev/nullrun nvm use stable in your shell and there you go.
5 Use npm to install yo, grunt-cli, and bower
simple:npm install --global yo bower grunt-cli6 Run yo and install angular generator
type yo at the command line and search for angular, then install it.yoWhat are grunt tasks? Minification of javascript files for example.
7 Run yo angular to generate angular
yo angular8 Use grunt serve to display an example front page
grunt serve9 Use yo to add angular directives, controllers etc.
run yo as needed.10 Develop your app
Simple enoughSaturday, October 5, 2013
Monday, August 19, 2013
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.
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.
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.
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
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.
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.
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
Thursday, July 25, 2013
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.
Tuesday, July 9, 2013
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
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.
Wednesday, May 15, 2013
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.
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.
Tuesday, April 2, 2013
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.
Sunday, March 31, 2013
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.
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.
Wednesday, March 13, 2013
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.
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.
Sunday, January 20, 2013
Too much time in the terminal
I just tried to use Ctrl-A to go to the beginning of the line in chrome :)
Thursday, January 10, 2013
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.
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.
Wednesday, January 2, 2013
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.
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