Roman Cheplyaka

Articles

Subscribe via RSS

2026

2024

Alice and Bob flipping coins puzzle 18 Mar

2023

2021

How much current does an active bass guitar draw from a 9V battery? 14 Nov
A data structure puzzle 24 May
Understanding modern Linux routing (and wg-quick) 27 Feb
My podcast editing workflow in REAPER 21 Feb

2020

StateT vs. IORef: a benchmark 29 Dec
Laptop vs. desktop for compiling Haskell code 22 Dec
system2 in R considered inadequate 11 Dec
Sort directories by the newest file 4 Dec
Don't buy tempered glass PC cases 3 Nov
Avoid the months() and years() functions from lubridate 30 Aug
Configuring PulseAudio for Audient EVO 4 10 Jul
How I integrate ghcid with vim/neovim 8 Jul
Which dynamic mic should you buy? 13 Jun
Visualizing Haskell heap profiles in 2020 14 May
Compile and link a Haskell package against a local C library 7 Apr
Binomial coefficients via integer division 22 Mar
Does micro-USB cable affect charging speed? 8 Mar
Break on NaN in gdb 11 Jan

2019

Significance level vs. the type I error chance, or how to interpret conditionals 21 Dec
Bioinformatics events in Europe in 2020 15 Dec
Long-term reminders 22 Nov
A blind microphone comparison 4 Sep
A curious associativity of the <$> operator 22 Jul
Decompose ContT 19 Jul
Why would you use ContT? 7 Jun
How (not) to convert CDouble to Double 14 May
Fix a torrent file encoding 7 May
Lazy validation 2 Mar
Surprises of the Haskell module system (part 2) 26 Jan
A better noise gate 12 Jan
Homology, similarity, and alignment 5 Jan

2018

Bioinformatics events in Europe in 2019 6 Dec
Tasty 1.2 supports dependencies between tests 1 Dec
How do I record a podcast remotely? SquadCast vs. Zencastr vs. Cast vs. other options 28 Oct
How to pass a logical matrix to RStan 24 Aug
Estimating the fraction of recurring events 22 Aug
logit() and logistic() functions in R 11 Aug
Can you cheat the Brier score? 9 Aug
Probability of a regex occurrence 1 Aug
Combine ChIP-seq peaks from multiple replicates via consensus voting 11 Jul
Sometimes all you need is to cut adapters 19 Jun
Encrypted reminders with Nudgemail 15 Jun
QuickCheck vs. SmallCheck 25 May
Disable Sony What's New notifications 14 May
What is this weird math letter? 11 May
GHC-style note snippet for Vim 2 May
Is differentiability arbitrary? 1 May
Rational approach to conferences 22 Apr
Seneca on social networks 14 Apr
The correct way to mark formulas in LaTeX 12 Apr
Install all R packages used in the code 2 Apr
Fighting referral spam 25 Mar
Notes on Jekyll 24 Mar
Export transactions from Santander 4 Mar
Undefined behavior with StablePtr in Haskell 3 Feb
RPM packager's cheat sheet 25 Jan
Asymmetry of costs in (t-)SNE 23 Jan
New patterns in tasty 8 Jan

2017

Where did all my probability go? 29 Dec
Bioinformatics events in Europe in 2018 27 Dec
Explained variance in PCA 11 Dec
Introduction to golden testing 4 Dec
Algebra of permutations in R 18 Nov
Estimate program run time 9 Nov
Does correlation imply causation? 28 Sep
How Booking.com manipulates you 17 Sep
Understanding Asymmetric Numeral Systems 20 Aug
Call an R function from C 18 Aug
6 ways to manage allocated memory in Haskell 6 Aug
Haskell library in a C project 26 Jul
Linux audio recording guide (PulseAudio or PipeWire) 21 Jul
All vk.com IP addresses 14 Jul
Can probability be greater than one? 30 Jun
Generic unification 17 Jun
On friendly contributing policies 12 Jun
Word vs. Int 5 Jun
Universally stateless monads 4 Jun
Why your podcast needs https 22 May
Convert time interval to number in R 18 May
Please help me with these open source Haskell projects 4 May
Generic zipWith 25 Apr
traverse-with-class 1.0 release 23 Apr
Disable weird indentation for R in vim 3 Apr
Deploying MathJax 2 Apr
Increase the open files limit on Linux 26 Mar
Haskell without GMP 10 Mar
Group data by month in R 22 Feb
Theory behind RSEM 29 Jan
How much space does an 8-bit integer occupy in C and Haskell? 25 Jan
Getting Random Things Done: fetching a random card from Trello 22 Jan
Nested monadic loops may cause space leaks 10 Jan

2016

optparse-applicative quick start 30 Dec
Matching country names by local alignment 11 Dec
Accuracy of quantile estimation through sampling 30 Nov
RNA-Seq normalization explained 28 Nov
Make ~/.pam_environment work again 8 Nov
Electoral vote distributions are polynomials 28 Oct
Mean-variance ceiling 20 Oct
The rule of 17 in volleyball 19 Oct
How to prepare a good pull request 18 Sep
A case for static linking in scientific computing 9 Sep
Extract the first n sequences from a FASTA file 23 Aug
Docker configuration on Fedora 18 Aug
Does it matter if Hask is (not) a category? 7 Aug
Debugging a CUPS Forbidden error 8 Jul
Install Fedora Linux on an encrypted SSD 28 Jun
Predicting a coin toss 14 Jun
Surprising reciprocity 2 Jun
Basic HTTP auth with Scotty 14 Apr
Descending sort in Haskell 2 Apr
rank vs. order in R 19 Mar
Reducing boilerplate in finally tagless style 3 Feb

2015

Fixing "Permission denied (publickey)" after an SSH upgrade 21 Dec
Torsors, midpoints, and homogeneous coordinates 16 Dec
Testing FFT with R 5 Dec
Simple FFT in Haskell 4 Dec
Static linking with ghc 26 Oct
MonadFix example: compiling regular expressions 2 Sep
Better YAML parsing 26 Jul
How Haskell handles signals 6 Jul
How to force a list 28 May
Announcing lambda prover 27 May
Smarter validation 2 May
Safe concurrent MySQL access in Haskell 17 Apr
Examples of monads in a dynamic language 22 Feb
Foldable, Traversable, and parametricity 12 Feb
Dealing with broken Haskell packages 9 Feb
Spiral similarity solves an IMO problem 31 Jan
Recognizing lists 29 Jan
Lexical analysis with parser combinators 2 Jan

2014

Denotational design does not work 31 Dec
Taking advantage of type synonyms in monad-control 26 Dec
Extensible effects: abstracting from the transformer 6 Dec
Rebalancing open source portfolio 1 Nov
Dependent Haskell 5 Sep
What you need to know about bracket 30 Jul
Type-based lift 15 Jul
How to run SQL actions in persistent 7 Jul
Two failed attempts at extensible effects 14 Jun
The problem with mtl 11 Jun
Avoid equational function definitions 9 May
Lens is unidiomatic Haskell 24 Apr
Setting up Samsung Wireless Printer on Linux 21 Apr
JSON validation combinators 20 Apr
Find out the type of an expression/function with typed holes 13 Mar
Happy, Alex, and GHC 7.8 8 Mar
cabal sandbox tips 5 Mar
tasty-0.8 and other news 3 Mar
My Haskell will 8 Feb

2013

Resources in Tasty (update) 29 Dec
Custom options in Tasty 20 Dec
On column positions in vim 14 Dec
Resources in Tasty 10 Dec
Why PVP doesn't work 5 Oct
Flavours of free applicative functors 31 Mar
gtraverse vs. gfoldl 29 Mar
Ergative verbs in programming 14 Mar
Generalizing generic fold 11 Mar
Open your name resolution 4 Mar
Announcing SmallCheck 1.0 19 Feb
Generic uncurry 29 Jan
Subtractable values are torsors 8 Jan

2012

Monads in dynamic languages 26 Dec
Surprises of the Haskell module system (part 1) 25 Dec
Haskell recipe: reading list of lines 25 Oct
Reasoning about space usage in Haskell 8 Apr
Composing monadic effects 2 Jan