## FaceTime Baby

My nephew Samvit, born in 2011, doesn’t talk much on the phone. It’s possibly because he didn’t talk much on the phone as a baby, but I’ve never been able to have a decent phone conversation with him (we get along really well when we meet, though). He talks a couple of lines and hands over the phone to his mother and runs off. If it’s a video call, he appears, says hi and disappears.

Berry (born in 2016), on the other hand, seems to have in a way “leapfrogged” the phone. We moved to London when she was five and a half months old, and since then we’ve kept in touch with my in-laws and other relatives primarily through video chat (FaceTime etc.). And so Berry has gotten used to seeing all these people on video, and has become extremely comfortable with the medium.

For example, when we were returning from our last Bangalore trip in December, we were worried that Berry would miss her grandparents tremendously. As it turned out, we landed in London and video called my in-laws, and Berry was babbling away as if there was no change in scene!

Berry has gotten so used to video calling that she doesn’t seem to get the “normal” voice call. Sure enough, she loves picking up the phone and holding it against her ear and saying “hello” and making pretend conversations (apparently she learnt this at her day care). But give her a phone and ask her to talk, and she goes quiet unless there’s another person appearing on screen.

Like there’s this one aunt of mine who is so tech-phobic that she doesn’t use video calls. And every time I call her she wants to hear Berry speak, except that Berry won’t speak because there is nobody on the screen! I’m now trying to figure out how to get this aunt to get comfortable with video calling just so that Berry can talk to her!

In that sense, Berry is a “video call” native. And I wouldn’t be surprised if it turns out that she’ll find it really hard to get comfortable with audio calls later on in life.

I’ll turn into one uncle now and say “kids nowadays… “

## More issues with Slack

A long time back I’d written about how Slack in some ways was like the old DBabble messaging and discussion group platform, except for one small difference – Slack didn’t have threaded conversations which meant that it was only possible to hold one thread of thought in a channel, significantly limiting discussion.

Since then, Slack has introduced threaded conversations, but done it in an atrocious manner. The same linear feed in each channel remains, but there’s now a way to reply to specific messages. However, even in this little implementation Slack has done worse than even WhatsApp – by default, unless you check one little checkbox, your reply will only be sent to the person who originally posted the message, and doesn’t really post the message on the group.

And if you click the checkbox, the message is displayed in the feed, but in a rather ungainly manner. And threads are only one level deep (this was one reason I used to prefer LiveJournal over blogspot back in the day – comments could be nested in the former, allowing for significantly superior discussions).

Anyway, the point of this post is not about threads. It’s about another bug/feature of Slack which makes it an extremely difficult tool to use, especially for people like me.

The problem is slack is that it nudges you towards sending shorter messages rather than longer messages. In fact, there’s no facility at all to send a long well-constructed argument unless you keep holding on to Shift+Enter everytime you need a new line. There is a “insert text snippet” feature, but that lacks richness of any kind – like bullet points, for example.

What this does is to force you to use Slack for quick messages only, or only share summaries. It’s possible that this is a design feature, intended to capture the lack of attention span of the “twitter generation”, but it makes it an incredibly hard platform to use to have real discussions.

And when Slack is the primary mode of communication in your company (some organisations have effectively done away with email for internal communications, preferring to put everything on Slack), there is no way at all to communicate nuance.

PS: It’s possible that the metric for someone at Slack is “number of messages sent”. And nudging users towards writing shorter messages can mean more messages are sent!

PS2: DBabble allowed for plenty of nuance, with plenty of space to write your messages and arguments.

## Coin change problem with change – Dijkstra’s Algorithm

The coin change problem is a well studied problem in Computer Science, and is a popular example given for teaching students Dynamic Programming. The problem is simple – given an amount and a set of coins, what is the minimum number of coins that can be used to pay that amount?

So, for example, if we have coins for 1,2,5,10,20,50,100 (like we do now in India), the easiest way to pay Rs. 11 is by using two coins – 10 and 1. If you have to pay Rs. 16, you can break it up as 10+5+1 and pay it using three coins.

The problem with the traditional formulation of the coin change problem is that it doesn’t involve “change” – the payer is not allowed to take back coins from the payee. So, for example, if you’ve to pay Rs. 99, you need to use 6 coins (50+20+20+5+2+2). On the other hand, if change is allowed, Rs. 99 can be paid using just 2 coins – pay Rs. 100 and get back Re. 1.

So how do you determine the way to pay using fewest coins when change is allowed? In other words, what happens to the coin change problems when negative coins can be used? (Paying 100 and getting back 1 is the same as paying 100 and (-1) ) .

Unfortunately, dynamic programming doesn’t work in this case, since we cannot process in a linear order. For example, the optimal way to pay 9 rupees when negatives are allowed is to break it up as (+10,-1), and calculating from 0 onwards (as we do in the DP) is not efficient.

For this reason, I’ve used an implementation of Dijkstra’s algorithm to determine the minimum number of coins to be used to pay any amount when cash back is allowed. Each amount is a node in the graph, with an edge between two amounts if the difference in amounts can be paid using a single coin. So there is an edge between 1 and 11 because the difference (10) can be paid using a single coin. Since cash back is allowed, the graph need not be directed.

So all we need to do to determine the way to pay each amount most optimally is to run Dijkstra’s algorithm starting from 0. The breadth first search has complexity \$latex O(M^2 n)\$ where $M$ is the maximum amount we want to pay, while $n$ is the number of coins.

I’ve implemented this algorithm using R, and the code can be found here. I’ve also used the algorithm to compute the number of coins to be used to pay all numbers between 1 and 10000 under different scenarios, and the results of that can be found here.

You can feel free to use this algorithm or code or results in any of your work, but make sure you provide appropriate credit!

PS: I’ve used “coin” here in a generic sense, in that it can mean “note” as well.

## Explaining UPI

I just paid my cook his salary for November. Given the cash crunch, I paid him through a bank transfer, using IMPS. Earlier today, my wife had asked him for his account details (last month I’d paid him on his wife’s account).

An hour back he sent me his account details (including account number and IFSC) via WhatsApp. I had to wait till I got home and got access to my laptop (Citibank app doesn’t let you add payees on mobile banking).

I get home, log in to Citibank Online. Add payee, which includes typing his bank account number twice. Get SMS asking me to confirm payee addition. I authorise payee. And after all this I am able to finally do the transfer – and I expect him to have got his money already.

For a long time I was wondering what the big deal with UPI was, given that IMPS is already fast enough. Having finally tried UPI earlier this week (it’s finally coming to iOS, but only available on ICICI now. And the implementation so far sucks, since you need to pull out your debit card for two factor authentication – defeating the point of UPI. I’m told it’s better on Android), I realise how much easier and safer the transaction would’ve been.

Firstly, the cook needn’t have sent me his account number. All I would need was his virtual payment address. I would then open my UPI app (in my case, iMobile) and click on “send money”. And then I’d add his virtual ID there, following which his name would appear. Two or three more clicks, and entering my PIN code, the transfer would be done.

No bank account number. Not even a mobile number or an email ID. Just a random string of characters would allow me to transfer money to him! And later I could give him my UPI ID, and next month onwards he could simply send me a request via UPI for his salary. And two clicks later it would be done!

Mint has reported that there are massive delays in merchants installing point of sale devices in response to the cash ban. Banks should instead seek to acquire merchants to accept money via UPI. It’s simple, it’s quick and it protects privacy.

In fact, if the bank sales staff now have bandwidth, it can be argued that all the planets have aligned for UPI to take off for merchant payments – people have less cash, point of sale devices are not available, and both merchants and shoppers have shown openness to cashless payments, and there is a push from the government.

If only the banks can bite…

## Siri Apps

So now that Apple has opened up Siri to third party developers (starting with iOS 10), I hope that app makers make use of this features clearly.

There are some apps, for example, that require inputs from time to time. My wife, for example, recently downloaded an app to track our daughter’s inputs and outputs.

The problem was that each time our daughter either input or output something, my wife had to unlock her iPhone, go to this app, and then use 3/4 more clicks to enter the necessary information. The complexity was so much that within a day she (wife) had stopped using it, and presently uninstalled the app.

This kind of app that needs frequent inputs seems ideally placed to get Siri integration. Imagine saying “Hey Siri. My baby just shat”, and the app gets immediately updated, and stuff. Given how powerful Siri already is, I don’t see any technical challenge in implementing this. The challenge, though, is on the product front, for apps to be able to use this judiciously.

PS: I just updated my laptop to MacOS Sierra, and so now have Siri on my Mac as well. only problem is that Siri on phone is so much more responsive than Siri on Mac. So when I want to call the Mac Siri, the phone Siri responds first, annoying me!

## Big data at HDFC Bank?

I had a bit of a creepy moment today – I must admit that, despite being a “data guy” and recommending clients to use data to make superior decisions (including customisations), it does appear creepy when you as a customer figure that your service provider has used data to customise your experience.

I’m in Barcelona, and wanted to withdraw cash from my Citibank account in India. Withdrew once, but when I wanted to withdraw more, the transaction didn’t go through (this happened multiple times, at multiple ATMs).

Frustrated, I figured that this might be due to some limits (on how much I could transact per day), and then decided to get around the limitations by transferring some money to my HDFC Bank account (since I’m carrying that debit card as well).

An hour after I’d transferred the money by IMPS, I put my HDFC Debit Card in my wallet and walk out, when I see an email from the bank informing me that my Debit Card is valid only in India, and with a link through which I could activate international transactions on it.

I’d never received such emails from HDFC Bank before, so this was surely in the “creepy” category. It might have been sent to me by the bank at “random”, but the odds of that are extremely low. So how did the bank anticipate that I might want to use my debit card here, and send me this email?

I have one possible explanation, and if this is indeed the case, I would be very very impressed with HDFC Bank. Apart from my debit card, I also have a credit card from HDFC Bank, which I’ve been using fairly regularly during my time in Europe (that my only other credit card is an AmEx, which is hardly accepted in Europe, makes this inevitable).

My last transaction on this credit card was to pay for lunch today, and so if HDFC Bank is tracking my transactions there, it knows that I’m currently in Europe (given the large number of EUR transactions recently, if not anything else).

Maybe the bank figured out that if I’m abroad, and have transferred money by IMPS (which implies urgency) into my account, then it is for the purpose of using my debit card here? And hence they sent me the email?

The counterargument to this is that this is not the first time I’ve IMPSd to my HDFC Bank account during this trip – the Income Tax and Service Tax websites don’t accept Citibank, so I routinely transfer to HDFC to make my tax payments. So my argument is not watertight.

Yet, if the above explanation as to why HDFC Bank guessed I was going to use my debit card is true, then there are several things that HDFC Bank has got right:

1. Linkage between my bank account and credit card. While I’ve associated both with the same customer ID, my experience with legacy systems in Indian financial institutions means actually associating them is really impressive
2. Tracking of my transactions on my credit card to know my whereabouts. If HDFC has done a diligent job of this, they know where exactly I’ve been over the last few months (provided I’ve used my card in these destinations of course).
3. Understanding why I use my account. While I’ve IMPSd several times in the past (as explained above), it’s all been in either the “service tax season” or “advance/self-assessment income tax season”. Mid-May is neither. So maybe HDFC Bank is guessing that this time it may not be for tax reasons?
4. Recognising I might want to use my debit card. If I’ve put money into my account and it’s not tax season, maybe they recognised I might want to use my debit card?

Maybe I might be giving them too much credit, and it just happened that the randomly sent out email came at the time when I’d just put the money into the account.

And the link they sent to enable international transactions worked! I had to use my laptop (it didn’t work on either the app or mobile web, so that’s one point deducted for them), but with a few clicks after logging into my bank account, I was able to enable the transactions!

So maybe there is reason to be impressed!

## The problem with Slack, and why it’s inferior to DBabble

When two of the organisations I’m associated with introduced me to the chatting app Slack, it reminded me of the chatting app DBabble (known to us in IIMB as BRacket) that was popular back when I was in college.

There were two primary reasons because of which Slack reminded me of DBabble. The first was the presence of forums/groups. There was a “General” that everyone in the organisation was part of, and then were other groups that you could choose to join and be a conversation in. The second was that you could not only converse on the fora, but also send personal messages to each other – something DBabble also enabled.

There are several reasons why Slack is superior to DBabble. Most importantly, you can tag people in your messages on forums and they get notified, so that they can respond – this is a critical feature for using it for work purposes.

Secondly, Slack integrates well with other tools that people use for work – such as email and a lot of development tools, for example (which one of the organisations I’m associated with uses heavily, but I’ve never got into that loop). Slack also has a very nice search feature that allows you to pull up discussions based on keywords, etc.

What Slack sorely lacks, which makes me miss DBabble like crazy, however, is threaded conversations. The conversation structure in each channel in Slack is linear – which means you can effectively have only one thread of conversation at a time.

When you have a large number of people on the channel, however, people might initiate several different threads of conversation. As things are, however, a Darwinian process means that all but one of them get unceremoniously cut out, and we end up having only one conversation.

It is also a function of whether Slack is used for synchronous or asynchronous messaging (former implies everyone replies immediately, latter means conversations can take their own time and there’s no urgency to participate immediately, like email, for example). My understanding is that the way it’s built, it can be used in both ways. My attempts to use it as an asynchronous messenger, however, have failed because some of the conversations I’ve tried to initiate have gotten buried above other conversations others on the channel have tried to start.

The problem with Slack is that it assumes that each forum will have only one active conversation at a time. Instead, if (like DBabble) it allows us to have different conversation threads, things can become a lot more efficient.

One of the nice features of forums on DBabble was that everytime you went to the forum, it would show you all the active threads by showing them in bold. DBabble allowed infinite levels of threading, and only messages that were unread (irrespective of which branch of which thread they were in) would be in bold, meaning you could follow all threads of conversation (this also proved problematic for some as we developed an OCD to “unbold” – read every single message on every forum we were part of).

Imagine how powerful threaded conversations can be at the corporate level especially when you can tag people in them – so you go to a forum, and can see all open discussions and see where your attention has been called, and contribute. Threading also means that you can carry out several different personal (1-to-1) conversations at a time without losing track of any.

It’s interesting that after DBabble (which also died after a later edition gave the option of “chat mode” which did away with threaded conversations) there has been no decent chat app that has come up that allows threaded conversations. Apart from possible bandwidth issues (which can happen when each message is suffixed with the full thread below it), I don’t see any reason this can’t be implemented!

I want my BRacket (DBabble) back. But then, chat has powerful network effects and there’s no use of me wanting a particular technology if sufficient number of other people don’t!