Alex Sanchez-Stern

Alex Sanchez-Stern

Hey I’m Alex Sanchez-Stern, I’m a PhD student at the University of California San Diego. I’m also part of the team at the UW that built Herbie. I graduated from the UW with a Masters degree in the Spring of 2016. I’m generally interested in using synthesis to elide complex domain details, and improving the usability of proof assistants through better proof search and new meta-language frameworks.


Herbie is a tool to help scientists and programmers write accurate floating point code more easily. You give it a floating point expression, and it tests it against hundreds of points to find a version that’s more accurate. Herbie is open source software, published at PLDI 2015.


Herbgrind is a debugging tool to help developers find the root cause of floating-point inaccuracy in large numerical software. It runs directly on program binaries, and produces reports about inaccuracies found that affect program outputs. Herbgrind is free and open source software, published at PLDI 2018.


You can reach me at my university email address. I’m also on GitHub.


So far I’ve co-authored a few papers:

Automatically Improving Accuracy for Floating Point Expressions

Toward a Standard Benchmark Format and Suite for Floating-Point Analysis

Finding Root Causes of Floating Point Error