Roadmap

This document sets out the high-level tasks which the vg development team hopes to accomplish in the next few versions of vg and beyond.

By Time

These are the things we hope to achieve on several planning horizons:

End of Year (12/21)

• Publish vg mpmap: revisions (Jordan, Jonas)
• HPRC transcriptomics with vg mpmap and rpvg (Jordan)
• Fast HPRC Giraffe (Xian)
  • Implement Distance Index 2, which also works as a snarl manager (Xian)
• vg deconstruct and Beagle to impute genotypes into partially-mapped and called data, as a PanGenie alternative (Erik, Andrea)
• Pipeline plan for long read Giraffe (Stephen)
• Functional surject pipeline
  • GBZ Paths (Adam)
  • Autoindex understanding of differences in node chopping (XG and GBZ made in parallel are currently completely different graphs when built from rGFA) (Maybe drop XG and use GBZ instead?)
  • Functional surject pipeline when coming from GBZ first; need something to surject onto.
  • Surjection option as a preset to build indexes for (so you can get an XG)
• Normalize a whole-genome graph and see if it improves mapping/calling (Robin)

Next 6 Months (3/22)

• User-facing, under-test Giraffe docs for HPRC graphs (Jordan)
  • Include getting alignments out in input GFA coordinates
• Long read Giraffe (Stephen)
• Adapt all snarl usage to go through libsnarls (Adam, Jordan)
  • Shim Snarl* as a non-Protobuf adapter type?
  • DI2 snarl manager with new API in libsnarls
• Less cruft in vg index #3144 (Adam, Jordan)
• Idiomatic Giraffe on long-node rGFA
  • Input and Output "stable" coordinates in GAF
  • Output rGFA-style cover of vg graph, using prioritization of existing paths as option, inventing paths if necessary
  • Node auto-chopping from rGFA is the last missing piece of #3126
  • Chopping overlay (Jordan)
  • Saving, loading, and using coordinate translations to/from node-coalesced, string-ID'd input GFA space
    • HG interface and implementation in libbdsg graphs?
  • Back-translate mappings
  • Implicit node chopping on GFA input
• RNA project
  • dbGAP access
  • Better splice junction identification/graph distance (Jordan)

Also:

• Eliminate vg::VG (Jordan)
  • Steal all the things only it can do away from it
• Default everything to GAF instead of GAM
  • mpGAF (Jordan, Jonas)
  • Also pgvf (Graph to graph)
  • Calls and snarls in one of these?
• Get rid of GFAKluge!
• Full subpath support in vg (Adam, Jordan)
  • HG API support (see old Github issue on handlegraph)
  • Plugging in to tools
• Drop pinchesAndCacti and sonlib
  • Drop Cactus-library-based snarl finder (Adam)
• Python bindings for libhandlegraph algorithms
  • Are they the right algorithms?

Next Year (9/22)

• Giraffe on really complex graphs: Non-minimum distance index? Linear layout distance index? Inject from GBWT path set mappings?
• Use memory-mapped graphs
  • For tube map, to enable interactive whole-genome use (Future data vis enthusiast)
  • For Giraffe
• Get GBWT build working in under 200 GB memory on 100m variants with fancy disk-backed in-progress GBWT implementation (need 300m random access vectors that grow independently)
• Support Erik's multi-level graph format when mature
• Redesign and reorganize little tools (Where should each manipulation live? Should some just be scripts you write?)
  • vg mod
  • vg chunk
  • vg circularize
  • vg view
  • vg paths

Running Projects

These are things we are working on, with no particular delivery date goal.

• Use of MCMC techniques in the genotyper with multipath alignments

Wishlist

These are things we would like to do eventually.

• Alignment
  • Adoption of the multipath alignment paradigm as the default
  • Graph-to-graph mapping (Xian)
• Variant Calling
  • Implementation of an HHGA-like machine learning based variant caller
  • Integration of variant calling and assembly polishing processes
  • Prune the zoo of TraversalFinders, and expose the useful ones to Python
• Visualization
  • Browser-free tube map
  • Better tube map handling of edge cases
    • No haplotypes on a node
    • Starting on a rare haplotype
• Infrastructure
  • Destructively modernize and unify IO
    • Eliminate VPKG framing if possible in favor of magic numbers everywhere
      • Resolve ensuing questions about GAM format
        • Just use GAF?
      • Handle things like GFA that need to manually sniff
    • Just save from the object; no more save_handle_graph
    • Magic format registration for libvgio magic numbers for loading
    • Depend on libvgio in libbdsg to do the IO there and pick the right handle graph implementation
  • Replace Protobuf internal formats with faster ones
  • Revision of ID assignment logic to allow deterministic node breaking
  • Accept gzipped GFA if practical (can't mmap)
  • Improved HandleGraph API
    • Abstract away node boundaries
    • View all sequence as C++17 string_views instead of sequence-owning strings
    • O(1) reverse complement DNAStringView
  • CMake-ify the main vg build
  • Eliminate old systems and their associated submodules, or factor them out into their own projects
    • vg vectorize could be its own project
      • Update vg vectorize to modern, system Vowpal Wabbit
      • Or pull it out into its own submodule and remove Vowpal Wabbit dependency from vg
    • Eliminate RocksDB from vg; everybody using vg map uses GCSA indexes now.
    • vg genotype
    • vg srpe
  • More cross-language support
    • Interoperate with Rust handle graph users/providers
    • Interoperate with Java handle graph users/providers