Uploaded January 2026 | Updated September 2026, 2 weeks ago
cppcon.org
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Lazy and Fast: Ranges Meet Parallelism in C++ - Daniel Anderson - CppCon 2025
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Recent advances in the C++ standard have introduced powerful features like ranges and parallel algorithms—both aimed at writing faster, cleaner, and more expressive code. Ranges offer lazy, on-demand computation that improves I/O efficiency and composability. Parallel algorithms, on the other hand, harness multitasking to speed up compute-heavy workloads.
At first glance, these two features seem like a perfect match: lazy evaluation to minimize I/O overhead, and parallelism to maximize throughput. However, in practice, they don’t play well together. Many range operations—especially those over non-random-access sources—are inherently sequential due to their lazy pull-based, one-element-at-a-time nature.
In this talk, we’ll explore a modern library technique that unlocks the synergy between lazy ranges and parallelism. You’ll see how to build lazy, composable range pipelines that are parallel-friendly—capable of efficiently expressing operations like filter, scan, and flatten without sacrificing performance or elegance. We’ll walk through real-world examples where these techniques deliver strong parallel speedups with minimal programming overhead.
Whether you’re a library designer, performance enthusiast, or just curious about making your range-based code scale, this talk will equip you with practical tools to bridge the gap between composability and parallelism in modern C++.
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Slides: github.com/CppCon/CppCon2025/blob/main/Presentations/Lazy_and_Fast.pptx
Work at Hudson River Trading (HRT): tinyurl.com/safxfctf
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Daniel Anderson
Daniel Anderson is an assistant teaching professor at Carnegie Mellon University, where he recently graduated with a PhD in computer science focusing on parallel computing and parallel algorithms. Daniel teaches algorithms classes to hundreds of undergraduate students and spends his remaining time writing C++ libraries that aim to make parallel computing easier and more accessible to non-experts. He is the recipient of a Best Paper Award from the ACM Symposium on Parallelism in Algorithms and Architecture (SPAA) conference.
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CppCon is the annual, week-long face-to-face gathering for the entire C++ community. The conference is organized by the C++ community for the community. You will enjoy inspirational talks and a friendly atmosphere designed to help attendees learn from each other, meet interesting people, and generally have a stimulating experience. Taking place this year in Aurora, Colorado, near the Denver airport, and including multiple diverse tracks, the conference will appeal to anyone from C++ novices to experts.
Annual CppCon Conference - cppcon.org
linkedin.com/company/cppcon
https://x.com/cppcon
facebook.com/CppConference
reddit.com/r/cppcon
https://mastodon.social/@CppCon
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Videos Filmed & Edited by Bash Films: BashFilms.com
YouTube Channel Managed by Digital Medium Ltd: events.digital-medium.co.uk
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#cpp #cplusplus #cppcon #cppprogramming #cplusplusprogramming #softwaredevelopment #softwareengineering #coding #code #computerscience #technology #technews #programming #programmer
cppcon.org
---
Lazy and Fast: Ranges Meet Parallelism in C++ - Daniel Anderson - CppCon 2025
---
Recent advances in the C++ standard have introduced powerful features like ranges and parallel algorithms—both aimed at writing faster, cleaner, and more expressive code. Ranges offer lazy, on-demand computation that improves I/O efficiency and composability. Parallel algorithms, on the other hand, harness multitasking to speed up compute-heavy workloads.
At first glance, these two features seem like a perfect match: lazy evaluation to minimize I/O overhead, and parallelism to maximize throughput. However, in practice, they don’t play well together. Many range operations—especially those over non-random-access sources—are inherently sequential due to their lazy pull-based, one-element-at-a-time nature.
In this talk, we’ll explore a modern library technique that unlocks the synergy between lazy ranges and parallelism. You’ll see how to build lazy, composable range pipelines that are parallel-friendly—capable of efficiently expressing operations like filter, scan, and flatten without sacrificing performance or elegance. We’ll walk through real-world examples where these techniques deliver strong parallel speedups with minimal programming overhead.
Whether you’re a library designer, performance enthusiast, or just curious about making your range-based code scale, this talk will equip you with practical tools to bridge the gap between composability and parallelism in modern C++.
---
Slides: github.com/CppCon/CppCon2025/blob/main/Presentations/Lazy_and_Fast.pptx
Work at Hudson River Trading (HRT): tinyurl.com/safxfctf
---
Daniel Anderson
Daniel Anderson is an assistant teaching professor at Carnegie Mellon University, where he recently graduated with a PhD in computer science focusing on parallel computing and parallel algorithms. Daniel teaches algorithms classes to hundreds of undergraduate students and spends his remaining time writing C++ libraries that aim to make parallel computing easier and more accessible to non-experts. He is the recipient of a Best Paper Award from the ACM Symposium on Parallelism in Algorithms and Architecture (SPAA) conference.
---
CppCon is the annual, week-long face-to-face gathering for the entire C++ community. The conference is organized by the C++ community for the community. You will enjoy inspirational talks and a friendly atmosphere designed to help attendees learn from each other, meet interesting people, and generally have a stimulating experience. Taking place this year in Aurora, Colorado, near the Denver airport, and including multiple diverse tracks, the conference will appeal to anyone from C++ novices to experts.
Annual CppCon Conference - cppcon.org
linkedin.com/company/cppcon
https://x.com/cppcon
facebook.com/CppConference
reddit.com/r/cppcon
https://mastodon.social/@CppCon
---
Videos Filmed & Edited by Bash Films: BashFilms.com
YouTube Channel Managed by Digital Medium Ltd: events.digital-medium.co.uk
---
#cpp #cplusplus #cppcon #cppprogramming #cplusplusprogramming #softwaredevelopment #softwareengineering #coding #code #computerscience #technology #technews #programming #programmer
