Update contributors.yml with Galin Bistrev personal info

_data/contributors.yml

@@ -21,7 +21,29 @@
   email: [email protected]
   education:  PhD Computer Science, University of Plovdiv “Paisii Hilendarski”, Plovdiv, Bulgaria (2013)
   active: 1
-
+
+- name: Galin Bistrev
+ info: "CERN Summer student 2025"
+ email: [email protected]
+ photo: Bistrev.png
+ education: "Nuclear and particle physics , Sofia University "St. Kliment  Ohridski , Bulgaria" 
+ current: 1
+ past_info:
+ title: "Implementing AD in CMS Combine"
+ description: This project aims to introduce automatic differentiation techniques into the CMS Combine tool. Combine is the primary statistical analysis tool used in CMS and is based on the RooFit software. 
+ Recently RooFit has started using automatic differentiation (AD) technology to aid minimization algorithms.
+ Computationally cheap gradients produced by AD can improve performance of the larger workflows in Combine by more than 5x as demonstrated at ICHEP.
+ The way how RooFit implements AD also benefits the shareability of likelihoods.
+ To get the likelihood gradient, RooFit transforms the likelihood from its internal representation to simple standalone C++ code, which is then used to generate the gradient code. 
+ This can help collaborators without RooFit and Combine expertise to work with likelihoods from Combine at a lower level. 
+ Adopting AD in Combine requires further collaboration between the parties.
+
+ This project aims to bring this AD support into Combine. Aspects include reducing some of the code in Combine in favor of more standard RooFit primitives; 
+ Implementing AD support for Combine-specific RooFit primitives; and writing benchmarks to showcase the benefits of RooFit AD in Combine. 
+ The student selected for this project will work with several high-energy physics codes as well as the LLVM compiler ecosystem.
+ mentors: Vasil Vassilev,David Lange,Jonas Rembser
+
+
 - name: Aaron Jomy
   photo: Aaron.jpg
   info: "Research Intern at CERN"
@@ -1201,3 +1223,4 @@
       report: |
         [Poster](/assets/presentations/LLVM2020_Clad.pdf){:target="_blank"}
       mentors: Vassil Vassilev, Alexander Penev   
+