
Subhrajit Das
PhD Scholar
Computer Science & Engineering
IIT Gandhinagar, Gujarat
India
About me
I am a PhD scholar in the Department of Computer Science and Engineering at the Indian Institute of Technology Gandhinagar, where I work with Prof. Abhishek Bichhawat and Prof. Yuvraj Patel. I am a member of the FUSS group and my current research explores harnessing the parallelism of modern CPUs in various systems workloads. My broader research interest includes CPU Parallelism, Distributed Systems, and Usability.
I also love sharing knowledge and have enjoyed being a Teaching Assistant for many of my favourite courses. I’ve had the great opportunity to give a few guest lectures and conduct a short course at the institute.
Education
Ph.D. in Computer Science and Engineering
Master of Technology in Computer Science and Engineering
Master of Science in Computer Science
Bachelor of Science (Honours) in Computer Science
Projects
WimpyScaler: Distributing GPU computations to Scalable Array of Wimpy Nodes
Team Contributor at IIT Gandhinagar & University of Edinburgh (Oct 2025 - Present)
- Designing a dynamically scalable compute cluster using hundreds of Raspberry Pi 5s (wimpy nodes) to distribute large-scale matrix multiplication workloads.
- Leveraging the DPDK stack for high-throughput, low-latency inter-node communication, enabling efficient workload distribution across the dynamic cluster.
- Optimizing on-node performance (scale-up) using ARM AdvSIMD (NEON) extensions, with the goal of benchmarking the aggregate scale-out compute power against high-end GPUs.
Resilient Lattice-Based Cryptography: Implementation on Quantum Hardware Using Qiskit Metal
Team Contributor at IIT Gandhinagar (Oct 2025 - Present)
- Ongoing project, selected in the Phase 1 of VSLID Design Contest 2026, investigating the implementation of lattice-based cryptographic algorithms on quantum hardware.
- Focuses on leveraging Qiskit Metal for designing and simulating quantum circuits. My role involves developing and optimizing quantum algorithms involving NTT for the targeted cryptographic schemes on the custom designed quantum hardware.
Accelerating Large Integer Arithmetic with Parallel Addition, Subtraction, and Vedic-Based Multiplication Using AVX512
M.Tech. Thesis Work
- Advisor: Prof. Abhishek Bichhawat, Co-advisor: Prof. Yuvraj Patel (The University of Edinburgh)
- Designed high-performance faster data-parallel algorithms for large integer addition and subtraction using
AVX512for most cases. - Achieved average execution-time speedup of 2.06x for addition and 2.32x for subtraction (up to 131k bits) compared to the GNU Multiple-Precision Arithmetic Library (
GMP). - Designed a faster Vedic-based multiplication algorithm for large integers using
AVX512-IFMAfor 256-bit operands, with execution-time speedup of 1.83x compared to theGMPlibrary. - Additionally, designed approximate variants of the proposed algorithms for large integer addition and multiplication, achieving average execution-time speedup of 2.52x and 2.80x, respectively, compared to
GMP.
Studies on Various Maximal Covering Location Problems using Genetic and Artificial Bee Colony Algorithms
M.Sc. Thesis Work
- Advisor: Prof. Priya Ranjan Sinha Mahapatra, Co-advisor: Dr. Soumen Atta
- Designed and implemented an algorithm for solving maximal covering location problems using genetic and artificial bee colony algorithms.
- Achieved optimal benchmark results with
CPLEXin 50% of cases, reducing the average computational time to 85.83 seconds, compared to over 1000 seconds for previous models, with an average gap of just 0.01%.
Reversible Multiplier Accumulate Unit (B.Sc. Project)
B.Sc. Project Work
- Designed a multiplier accumulate unit using reversible gates for low power consumption and heat dissipation.
Instant Payment Gateway (IPG)
Team Contributor
- Engineered an instant payment system using Parallel and Distributed Systems concepts.
- Facilitated seamless and secure interoperability between parties, similar to UPI.
- Implemented efficient transaction processing with load balancing, fault tolerance, and concurrency control to ensure high availability and scalability.
TennisServe: A Parallel Game Matching Server with OpenMP & MPI
Individual Contributor
- Developed a simulation of a tennis game matching server where multiple players send requests for games: singles, doubles, male, female, or mixed.
- Utilized OpenMP threads to handle client requests and
MPIcalls for player communication. - Managed the availability of limited tennis courts (4 courts) to continuously match players’ requests.
- Completed as part of the Parallel and Distributed Course at IIT Gandhinagar.
Teaching Experience
Teaching Assistant
- Assisted for the courses such as Distributed Systems and Cloud Computing, Computer & Network Security, Compilers, and Data Structures and Algorithms - I.
Guest Lectures on SIMD and Code Profiling
- Given a couple of guest lectures on exploiting x86-64 data parallelism using compiler auto-vectorization, intrinsics and also profiling code using Linux perf and relevant syscalls for the course CS 612 - Computer Systems.
Guest Lecture on RAID
- Given a guest lecture on RAID for the course Operating Systems (CS 330).
Principal Instructor
- Served as the Principal Instructor for a Short Course titled “Code Profiling and Optimization” during Semester-I, 2024-25.
- Topics covered: compiler flags (GCC/ICX), debugging (GDB), performance tools (
timespec,rusage,rdtsc), profiling tools (perf,valgrind), and optimization strategies (caching, memory, vectorization, parallelization).
Publications
DigitsOnTurbo: Leveraging SIMD for Accelerating Large-number Arithmetic
Online Authentication Habits of Indian Users
Updates
Selected for the Director's PhD Fellowship at the IIT Gandhinagar