Leonid Rozenberg, Developer in New York, NY, United States
Leonid is available for hire
Hire Leonid

Leonid Rozenberg

Verified Expert  in Engineering

Unix Shell Scripting Developer

New York, NY, United States
Toptal Member Since
July 9, 2017

Leonid is an experienced developer who specializes in numerical tools, using various functional languages (OCaml, F#, Haskell, Erlang) as well as platforms more suited towards computation (Matlab, Python) and statistics (R). He has extensive experience in finance and is knowledgeable about modern machine learning techniques.



Preferred Environment

Windows, Linux, MacOS

The most amazing...

...project I've worked on is a large Hidden Markov Model for posterior allele distribution inference.

Work Experience

Technology Specialist

2015 - 2018
Mount Sinai
  • Investigated algorithms for protein binding prediction: for example, given an amino acid sequence and associated MHC molecule, predict the IC50 binding value.
  • Contributed to open-source projects, including a machine learning library and process management tool. Worked with extensive online open-source reviews and collaborations.
  • Researched HLA inference algorithms from whole-exome sequencing. Built a probabilistic model of alignment leading to posterior allele distribution.
Technologies: OCaml


2013 - 2014
Self Employed
  • Acted as CTO of a small "agtech" startup. Created CRUD websites that displayed relevant pesticide information. Coordinated Amazon Turk tasks to extract and normalize data.
  • Researched predictive models for optimal seed selection.
  • Pursed algorithmic negotiation consultancy. Created a prototype library to describe negotiations and then find Pareto optimal solutions.
  • Developed and presented several pitches. Interviewed clients and negotiators.
  • Created a social media platform that leveraged Twitter into a debate platform.
Technologies: PostgreSQL, Ruby on Rails (RoR), Ruby, Python, Erlang, Haskell, OCaml


2012 - 2013
Bank for International Settlements
  • Consulted for the risk and economic policy research group. Developed and maintained a research and graphing framework.
  • Helped to develop libraries to facilitate Matlab analysis in parallel.
  • Developed features and fixed bugs as requested by bank researchers.
  • Translated several thousand lines of Visual Basic to C#. Debugged STATA simulations.
  • Helped to coordinate monthly Scrum and sprint planning.
Technologies: MATLAB, C#

Risk Developer

2010 - 2012
  • Priced and simulated several thousand metal portfolios, spanning numerous contract types and international markets, to drive a custom non-parametric VaR estimate, in F#.
  • Priced multi-leg, curve-dependent options using Monte Carlo techniques and forward curve decompositions (F#, Matlab, C++).
  • Coordinated worldwide colleagues in ensuring accuracy in price and position reporting and reconciling VaR measurements.
  • Integrated price sources into a custom library, allowing us to have consistent prices across illiquid markets or during non-trading hours.
  • Estimated extreme-value statistics, peak over threshold, and parametric VaR for all energy related portfolios.
Technologies: MATLAB, C++, Azure Machine Learning, F#


2007 - 2010
Vermillion Asset Management
  • Developed tools in F# for pricing and hedging commodity related options. Tools were used in a real time and position simulation scenarios.
  • Supported the quantitative aspects of an equity volatility strategy. Created tools for traders to monitor computationally demanding changes in equity options markets, inter-day and in real-time (F#, VBA, Python.).
  • Implemented statistical arbitrage infrastructure for time series research. Created and traded stock strategies.
  • Researched and implemented parameter estimation methods to correct for bias and variance.
  • Collaborated with other traders and developers on strategies and outlook.
Technologies: Visual Basic for Applications (VBA), Microsoft Excel, Python, F#

Quantitative Researcher / Assistant Trader

2004 - 2007
Jane Street
  • Modeled statistical arbitrage strategies using tick data on a custom built distributed computing environment.
  • Co-developed a second generation, high performance, and automated trading platform.
  • Wrote the core logic for several automated high-frequency trading strategies, using the newly developed platform.
  • Was responsible for the day-to-day operation, maintenance, correctness, and disaster conditions of the automated trading systems.
  • Leveraged trader input and my own trading experience to develop parameters and automated strategies to enhance performance. Corrected source code and released new versions of the strategy as appropriate.
Technologies: C++, Visual Basic for Applications (VBA), Microsoft Excel, OCaml

OCaml Math Library

A reformulation of common mathematical, statistical, and machine learning routines written in OCaml. The intent is to use sophisticated types to inform the logic and semantics of the routines and algorithms.
1999 - 2004

Bachelor of Science Degree in Computer Science

California Institute of Technology - Pasadena, CA


Scikit-learn, SciPy, Pandas, BLAS, LAPACK


Microsoft Excel, Vim Text Editor, Azure Machine Learning, gnuplot, MATLAB


Functional Programming, Object-oriented Programming (OOP)


Linux, MacOS, Unix, Windows


OCaml, Visual Basic for Applications (VBA), R, F#, SQL, Ruby, C#, C, Erlang, Octave, Haskell, Erlang (OTP), C++, Python

Industry Expertise



.NET, Ruby on Rails (RoR), Django


SQLite, PostgreSQL


Statistics, Regression Modeling, Classification, Unix Shell Scripting, Machine Learning, Matrix Algebra, Bayesian Statistics

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.


Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring