hellsten + cs   43

Consistent Hash Rings Explained Simply
- you may want to take a URL and get back the server the website is hosted on.

- The problem of mimicking a hash table when the number of locations are constantly changing was exactly why consistent hashing was invented.

- For 2,000 keys spread across 100 locations, you now need to move only 20 keys to a new location if 1 location with only 20 keys goes down.

- This is the main benefit of consistent hashing: you now no longer need to move so many things just because one location has disappea...
algorithms  algorithm  distributed  consistent-hash  hash  cs 
5 weeks ago by hellsten
The On-Line Encyclopedia of Integer Sequences® (OEIS®)
The On-Line Encyclopedia of Integer Sequences® (OEIS®)

Most people use the OEIS to get information about a particular number sequence. If you are a new visitor, then you might ask the database if it can recognize your favorite sequence, if you have one. To do this, go to the main look-up page, enter the sequence, and click Search. You could also look for your sequence in the Index.
integers  math  mathematics  sequences  reference  cs  list  advent-of-code  algorithms 
11 weeks ago by hellsten
Decision Tables • Hillel Wayne
A decision table is a means of concisely representing branching and conditional computations. In the most basic form, you have some columns that represent the “inputs” as booleans and some columns that represent outputs and effects. It looks like this:
programming  software-engineering  cs 
october 2018 by hellsten
math-as-code/README.md at master · Jam3/math-as-code
This is a reference to ease developers into mathematical notation by showing comparisons with JavaScript code.

Motivation: Academic papers can be intimidating for self-taught game and graphics programmers. :)

s - italic lowercase letters for scalars (e.g. a number)
x - bold lowercase letters for vectors (e.g. a 2D point)
A - bold uppercase letters for matrices (e.g. a 3D transformation)
θ - italic lowercase Greek letters for constants and special variables (e.g. polar angle θ, theta)
math  mathematics  cheatsheet  best  programming  cs  faq  academic  papers  notation 
november 2016 by hellsten
Dataflow programming - Wikipedia, the free encyclopedia
In computer programming, dataflow programming is a programming paradigm that models a program as a directed graph of the data flowing between operations, thus implementing dataflow principles and architecture. Dataflow programming languages share some features of functional languages, and were generally developed in order to bring some functional concepts to a language more suitable for numeric processing. Some authors use the term Datastream instead of Dataflow to avoid confusion with Dataflow Computing or Dataflow architecture, based on an indeterministic machine paradigm. Dataflow programming was pioneered by Jack Dennis and his graduate students at MIT in the 1960s.
workflow  dataflow  programming  cs  architecture 
august 2016 by hellsten
Ridesharing Algorithms in TransLoc OnDemand — TransLoc TechLog — Medium
At the core of TransLoc OnDemand is the scheduling algorithm. The inputs into the algorithm are rides and vehicles.
Each vehicle has the following attributes:
Current Location
Current Passenger Load
Total Passenger Capacity
Each ride has the following attributes:
Origin & Destination
Number of Passengers
Desired Pickup or Dropoff Time (if scheduled in advance)
Candidate Vehicles (determined by other parts of our system)
The problem to solve is two-fold:
Which vehicles should serve wh...
algorithm  cs  transport  location  traffic  maps 
march 2016 by hellsten
Two Generals' Problem - Wikipedia, the free encyclopedia
Illustrating the problem[edit]
The first general may start by sending a message "Attack at 0900 on August 4." However, once dispatched, the first general has no idea whether or not the messenger got through. This uncertainty may lead the first general to hesitate to attack due to the risk of being the sole attacker.
To be sure, the second general may send a confirmation back to the first: "I received your message and will attack at 0900 on August 4." However, the messenger carrying the confirmation could face capture and the second general may hesitate, knowing that the first might hold back without the confirmation.
Further confirmations may seem like a solution - let the first general send a second confirmation: "I received your confirmation of the planned attack at 0900 on August 4." However, this new messenger from the first general is liable to be captured too. Thus it quickly becomes evident that no matter how many rounds of confirmation are made, there is no way to guarantee the second requirement that each general be sure the other has agreed to the attack plan. Whichever general sends the final messenger will always be left wondering whether the messenger got through.
messaging  architecture  two-generals  cs  strategy 
march 2015 by hellsten
Understanding Computation
These are foundational concepts that you’ll wish you’d always known, digested and presented in a way that makes sense; universal truths which are interesting in their own right, but which also give you a better understanding of the way you do your job and the limitations of what’s possible.

Over the course of the book, you will:

implement two different interpreters, and a compiler, for a toy programming language;
build simulations of deterministic and nondeterministic finite automata, pushdown automata and Turing machines;
build a simple implementation of regular expressions from scratch;
construct a lexical analyzer and LL parser for a toy programming language;
write Ruby programs in the style of the lambda calculus;
implement the lambda calculus directly in Ruby;
implement other universal systems (partial recursive functions, the SKI combinator calculus, Iota, tag systems and cyclic tag systems) in Ruby;
extend a program to make it compute its own source code;
investigate programs that can’t be written in Ruby; and
build a simple type system.
To find out more, please check out the table of contents, download a sample chapter, read what people are saying on Twitter, watch some related videos, download the example code, and get in touch with any questions or comments.
cs  programming  toread  ruby 
january 2015 by hellsten
fogus: 10 Technical Papers Every Programmer Should Read (At Least Twice)
When I first started writing, one of the pieces of advice that I heard was that you should always imagine that you are writing to a particular person.

The gist is that the primary sources of complexity in our programs are caused by mutable state. With that as the premise, the authors build the idea of “functional relational programming” that espouses minimizing mutable state, moving whatever remains into relations, and then manipulating said relations using a declarative programming language. Simple right? Well, yes it is simple; and that’s what makes it so difficult.
programming  cs  functional-programming  immutable  mutable  best 
december 2014 by hellsten
programming practices - Torvalds' quote about good programmer - Programmers
"Bad programmers worry about the code. Good programmers worry about data structures and their relationships."
linus-torvalds  programming  cs 
september 2012 by hellsten
The Brooklyn Investor: Wells Fargo-Goldman Sachs Merger
I don't know about MS, but I still like GS and think they will do very well over time. I do believe that this conservatism is short-term based on the uncertainties and heightened risk of a total financial blowup in Europe (and GS doesn't want to get caught with it's pants down; there would be no political will for any sort of rescue next time around).
july 2012 by hellsten
This led to poor returns for our
investments in stocks such as Credit Suisse (1.8%), Barclays (1.9%),
Banco Santander (1.7%) and Banco Bilboa Vizcaya (1.8%). We think the
selling in these stocks is overdone, however, since, in our view, these
companies are diversified global giants with limited exposure to their
troubled local markets. We believe the disconnect between the market
performance and underlying fundamentals of these companies will
ultimately be resolved in the form of higher valuations.

The market spent the second quarter climbing the proverbial “wall of
worry,” with no fewer than three different trends—slowing U.S. growth,
China’s economy and the debt crisis in Europe—pressuring returns. We
believe these fears are fully reflected in market prices at this point,
which was illustrated on the final day of the quarter when news of
Europe’s rescue plan for Spanish banks drove most global markets up
2% to 3% in the session. In our view, this turnaround illustrates the pentup buying power ready to go to work in the market as soon as the
headlines begin to exceed investors’ currently depressed expectations.
david-dreman  cs 
july 2012 by hellsten
Bargains Among Battered European Bank Stocks? Oakmark Intl’s David Herro Makes His Case
To understand Herro’s interest in the sector, consider Credit Suisse, one of Switzerland’s largest banks. The Swiss central bank advised Credit Suisse, and UBS ( UBS), on June 14th to increase their capital base to build a bigger buffer if the Euro begins to crumble. (Switzerland is not a part of the Euro, but will be impacted it there are any exits.) Credit Suisse said its capital base is just fine, thank you. Still, there’s been little good news in its numbers lately. Earnings have taken a serious hit.

“We already know that the Basel 3 [capital] requirements for Swiss financial institutions are some of the most stringent in the world, another example of Swiss governmental agencies’ extreme conservatism. We take capital strength and solvency very seriously, as it helps protect downside risk when investing. With little exposure to sovereign debt, excellent liquidity and a strong balance sheet that is growing stronger, Credit Suisse’s financial strength satisfies our investment criteria.”
david-herro  cs 
july 2012 by hellsten
Oakmark’s Herro Remains Bullish On STD, CS, BNP Paribas & Daimler - Focus on Funds - Barrons.com
three of the fund’s top four holdings being European banks. Those included Credit Suisse (CS) and BNP Paribas (BNPQY).
oakmark  bnp  cs  david-herro 
march 2012 by hellsten
Value Investor Insights - David Herro.pdf
We assume the euro continues to weaken

the sell-off in European share prices – those business values haven’t materially changed

we think BNP shares are irrationally priced at less than 5x earnings and a 7% dividend yield

Credit Suisse:
The projected return on equity for next year is 15%, but the shares trade for only 85% of book value.

we’d argue that the combined business is worth at least 2x book value. On today’s book value, that would result in a share price of around 55 Swiss francs
european-investing  european-banks  oakmark  david-herro  value-investing  bnp  cs  value-investing 
january 2012 by hellsten
View Idea
So, my point is that the CS wealth management business is worth 17-20 times while the one for MS is probalby worth 14-15x (if that). The CS model blows the MS and MER model. Just look at the metrics. Much faster growth for CS, higher margins, more franchise value. Also, CS and UBS have more exposure to areas like Asia where there is booming growth in wealth.
cs  value-investing  value-investing 
november 2011 by hellsten
European Banks - When the leverage is low, the jewels stand out
However only the best banks are likely to return back to 15%
- Eg BNP Paribas, CS
- Julius Baer: no major capital constraint

At 10% CET1 ratio, the sector’s ROTE would decline to 10%
- It would take a 15% increase in the revenues for the ROTE to return to 15%
- At 9% CET1, the necessary increase in revenues would still have to be 10%

PIGS exposure as a % of tangible equity
BNPP 17%
CS 11%
UBS 7%
Santander 118%

Worst-case scenario impact on tangible equity:
BNPP ~4-8%
CS ~2-5%
UBS ~2-4%

Growth in TBVPS is key (2010-2012E):
CS 16% - 3rd highest
UBS 14%
BNPP 13%
Julius Bear 11%
cs  bnp  julius-baer  european-banks  2011  research  investing  value-investing  ubs 
september 2011 by hellsten
“It’s time to open your eyes” | paperJam
“Actually the most amazing was Credit Suisse. In 2003 we did a ‘risk profiler’ with them, because they had quite a tough time during the meltdown of the Internet bubble. Credit Suisse was quite an aggressive investor in the Internet bubble, while UBS was not, and was close to bankruptcy in 2003. Then the head of private banking came to my office and he asked, ‘so what can you recommend we change.’

1) The planning problem: “People keep postponing financial decisions, because of uncertainty in the market.” Ultimately that leads to no decisions ever being made.

2) The adaptive learners problem:
“In financial markets, if you burn your fingers, that’s the time to light a second candle.”

3) Illusions of control: “Most people think they can do market timing,”
4) Overconfidence: “We all think we are better than average.
cs  value-investing  behavioral-investing  psychology  banks  ubs 
september 2011 by hellsten
Nomura European Banks Outlook 2011
French banks: We see an attractive risk/reward, with BNP Paribas ourtop pick.
Investment banks: We are underweight versus commercial banks, favouring UBS over Credit Suisse.

Italian banks: While the least risky of southern European economies,we see few catalysts, preferring Intesa over UniCredit.
Nordic banks: We remain overweight the region on better growth andcapital, with DNBNOR and Swedbank our top picks.
Spanish banks: We remain underweight as more capital is needed, butwe believe trading opportunities could arise for Santander.
UK banks: We believe Lloyds offers good upside potential, but we cannotjustify the valuation for RBS.
our preferred stock is BNP Paribas, which benefits from goodrisk management, strong capital and hidden value from the Fortis acquisition.
european-banks  2011  cs  bnp  best  value-investing  ubs 
september 2011 by hellsten
Global Investment Banks - Regulatory Arbitrage series: Overweight European over US Investment Banks
We remain OW IBs over traditional credit banks. Our
pecking order is UBS, CSG, MS, BNPP, SG, BARC, GS and DB.

European IBs reflect our preference for i) well capitalised banks with
attractive valuation, ii) relatively resilient private banking exposure, iii) equity
gearing over fixed income within IBs and…

Number of positives (Valuation, Capital, Business Mix, IB revenue mix, Regulatory arbitrage)
CS 4
Morgan Stanley 3
BNP Paribas 3

Global IB top picks - UBS and CSG: own both in 2011

French Banks more attractive than DB and Barclays - top pick BNPP

UBS and CS trade at 0.6x implied P/BV on average for the IB division,
compared to 1.0x for the rest of the IB peers. This is unwarranted in our vie

GS: our assumed buyback of $15.4bn or 17% of market cap (28% at current price)

Private banking/brokerage provides a source of relatively stable cash flow generation
across the cycle, and overall, remains one of the most profitable banking businesses…
cs  ubs  bnp  european-banks  us-banks  2011  analysis  best 
september 2011 by hellsten
Dailymotion - Herro Likes European Banks With Strong Retail Franchises - a News & Politics video
someone who looks for well-managed companies selling at ridiculously low prices. Are you finding any at the moment?

Yes… Valuations are very subdued.

You're fairly highly exposed to European banks. Are you not at all concerned about systematic risk?

We are concerned and something you have to watch. The worst-case scenario has a very low probability. Contagion, collapse.

European financials are priced for very difficult times. Times will be less difficult than the price inclines.

Are you adding to those positions?

Yes, especially to those that have a strong asset management, strong franchises retail banking, BNP Paribas perfect example. They've been hit because they are part of this region

At what point do you loose patience?

We loose patience if we see something that disrupts the value creation process

Credit Suisse is creating value all the time. The price is going down, down, and the business value is going up up. The value gap is going up up. As far as timing, who knows
david-herro  value-investing  european-banks  2011  oakmark  bnp  cs 
september 2011 by hellsten
Private banks eye UBS's disgruntled rich clients | Reuters
"Last time, UBS lost masses of funds. We were in receipt of some of it, Credit Suisse did better," said a London based private banker at a rival global institution, speaking on condition of anonymity.
european-banks  cs  usb 
september 2011 by hellsten
UBS’s Trading Loss May Revive Calls for Gruebel to Shrink Investment Bank - Bloomberg
$2 billion trading loss may revive calls for Chief Executive Officer Oswald Gruebel to further shrink the investment bank.

The loss amounts to about 4 percent of UBS’s tangible equity and 5 percent of its core Tier 1 capital, making it “large, but digestible,” the Goldman Sachs analysts said.

Analysts had suggested in July, when UBS announced the review, that the bank would scale back its investment bank to conserve capital and bolster profitability.

While competitors have been cutting risk, UBS has been increasing value at risk, a measure of potential trading losses on a given day.

Under his leadership, the Zurich-based bank started cutting its holdings of U.S. subprime mortgage bonds in 2006, when competitors -- including UBS -- were still buying them.
ubs  european-banks  cs  2011 
september 2011 by hellsten
Why We Like Select European Banks
Our European bank holdings possess many of these competitive advantages while trading at very compelling valuations.

Our Swiss banks (Credit Suisse, UBS and Julius Baer) have very large and profitable private-banking operations that are both low-risk and generate a tremendous amount of free cash flow.

All three banks have strong balance sheets and capital ratios that are nearly 2x the European banking average.

Finally, these banks generate returns on capital of around 20% while trading at very low adjusted price/book and price/earnings.

Our more traditional bank holdings include BNP Paribas, Banco Santander, Intesa Sanpaolo and Bank of Ireland.

BNP, one of the largest banking franchises in Europe, has a diversified revenue base and it generates very high levels of profitability. It’s important to put BNP’s exposure to Greece into perspective – it represents less then 1% of the bank's total assets.
europe  value-investing  oakmark  2011  contrarian-investing  financials  banks  bnp  cs  ubs  european-banks 
august 2011 by hellsten

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