{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2019:55VGRSUBA5Y432L4AXQG4QYDQY","short_pith_number":"pith:55VGRSUB","canonical_record":{"source":{"id":"1912.07696","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.MS","submitted_at":"2019-12-16T20:45:42Z","cross_cats_sorted":[],"title_canon_sha256":"81a263ba8da469d474132c1c5ff8f31908ac7c3043322d4a0d41e512f3bc321e","abstract_canon_sha256":"0b9f63af3b244108f73b79707bd98a0cd5cb941e44d61a3236ca185135f53f83"},"schema_version":"1.0"},"canonical_sha256":"ef6a68ca810771cde97c05e06e43038603f99cac58772a4fbda893f30018e432","source":{"kind":"arxiv","id":"1912.07696","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1912.07696","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"arxiv_version","alias_value":"1912.07696v2","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1912.07696","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"pith_short_12","alias_value":"55VGRSUBA5Y4","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"pith_short_16","alias_value":"55VGRSUBA5Y432L4","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"pith_short_8","alias_value":"55VGRSUB","created_at":"2026-07-05T03:26:12Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2019:55VGRSUBA5Y432L4AXQG4QYDQY","target":"record","payload":{"canonical_record":{"source":{"id":"1912.07696","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.MS","submitted_at":"2019-12-16T20:45:42Z","cross_cats_sorted":[],"title_canon_sha256":"81a263ba8da469d474132c1c5ff8f31908ac7c3043322d4a0d41e512f3bc321e","abstract_canon_sha256":"0b9f63af3b244108f73b79707bd98a0cd5cb941e44d61a3236ca185135f53f83"},"schema_version":"1.0"},"canonical_sha256":"ef6a68ca810771cde97c05e06e43038603f99cac58772a4fbda893f30018e432","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T03:26:12.309158Z","signature_b64":"P/f5GuOe8Ce041ScCLedpEcfxDc9u2kJmspW3Okladp8o48Wflib/QB4LCaqBfXhh3/itMzbhV6vzxfE79WyDw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"ef6a68ca810771cde97c05e06e43038603f99cac58772a4fbda893f30018e432","last_reissued_at":"2026-07-05T03:26:12.308721Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T03:26:12.308721Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1912.07696","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T03:26:12Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"PH4fQfHmlZucAd3WmENEYhrzh3h2C5LC4D8aUpcyxKjBd0HDZg3n1HRLUZSVNw3P12R8j2S51fXMUdSz/ou0Cg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-01T08:00:17.812159Z"},"content_sha256":"77074c6ad8d13271e31889eff30021417e55f47abf8ea819c4865737a09bfe09","schema_version":"1.0","event_id":"sha256:77074c6ad8d13271e31889eff30021417e55f47abf8ea819c4865737a09bfe09"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2019:55VGRSUBA5Y432L4AXQG4QYDQY","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"PETSc TSAdjoint: a discrete adjoint ODE solver for first-order and second-order sensitivity analysis","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cs.MS","authors_text":"Barry F. Smith, Emil M. Constantinescu, Hong Zhang","submitted_at":"2019-12-16T20:45:42Z","abstract_excerpt":"We present a new software system PETSc TSAdjoint for first-order and second-order adjoint sensitivity analysis of time-dependent nonlinear differential equations. The derivative calculation in PETSc TSAdjoint is essentially a high-level algorithmic differentiation process. The adjoint models are derived by differentiating the timestepping algorithms and implemented based on the parallel infrastructure in PETSc. Full differentiation of the library code including MPI routines thus is avoided, and users do not need to derive their own adjoint models for their specific applications. PETSc TSAdjoin"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1912.07696","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/1912.07696/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T03:26:12Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"JqpmwOlWbbowR0cR9Typ/Ono4PMNTPvh/ILQ3QjrBpBiikqfUlzFJhV9g7KkIkcvdAjypY4pa3tbVxnirIFaBg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-01T08:00:17.812710Z"},"content_sha256":"4ba3107c87f9fa78d77933f3fe50138f5d4389349fd57775dbf336e1b2b25872","schema_version":"1.0","event_id":"sha256:4ba3107c87f9fa78d77933f3fe50138f5d4389349fd57775dbf336e1b2b25872"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/55VGRSUBA5Y432L4AXQG4QYDQY/bundle.json","state_url":"https://pith.science/pith/55VGRSUBA5Y432L4AXQG4QYDQY/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/55VGRSUBA5Y432L4AXQG4QYDQY/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-08-01T08:00:17Z","links":{"resolver":"https://pith.science/pith/55VGRSUBA5Y432L4AXQG4QYDQY","bundle":"https://pith.science/pith/55VGRSUBA5Y432L4AXQG4QYDQY/bundle.json","state":"https://pith.science/pith/55VGRSUBA5Y432L4AXQG4QYDQY/state.json","well_known_bundle":"https://pith.science/.well-known/pith/55VGRSUBA5Y432L4AXQG4QYDQY/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:55VGRSUBA5Y432L4AXQG4QYDQY","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"0b9f63af3b244108f73b79707bd98a0cd5cb941e44d61a3236ca185135f53f83","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.MS","submitted_at":"2019-12-16T20:45:42Z","title_canon_sha256":"81a263ba8da469d474132c1c5ff8f31908ac7c3043322d4a0d41e512f3bc321e"},"schema_version":"1.0","source":{"id":"1912.07696","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1912.07696","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"arxiv_version","alias_value":"1912.07696v2","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1912.07696","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"pith_short_12","alias_value":"55VGRSUBA5Y4","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"pith_short_16","alias_value":"55VGRSUBA5Y432L4","created_at":"2026-07-05T03:26:12Z"},{"alias_kind":"pith_short_8","alias_value":"55VGRSUB","created_at":"2026-07-05T03:26:12Z"}],"graph_snapshots":[{"event_id":"sha256:4ba3107c87f9fa78d77933f3fe50138f5d4389349fd57775dbf336e1b2b25872","target":"graph","created_at":"2026-07-05T03:26:12Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/1912.07696/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"We present a new software system PETSc TSAdjoint for first-order and second-order adjoint sensitivity analysis of time-dependent nonlinear differential equations. The derivative calculation in PETSc TSAdjoint is essentially a high-level algorithmic differentiation process. The adjoint models are derived by differentiating the timestepping algorithms and implemented based on the parallel infrastructure in PETSc. Full differentiation of the library code including MPI routines thus is avoided, and users do not need to derive their own adjoint models for their specific applications. PETSc TSAdjoin","authors_text":"Barry F. Smith, Emil M. Constantinescu, Hong Zhang","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.MS","submitted_at":"2019-12-16T20:45:42Z","title":"PETSc TSAdjoint: a discrete adjoint ODE solver for first-order and second-order sensitivity analysis"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1912.07696","kind":"arxiv","version":2},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:77074c6ad8d13271e31889eff30021417e55f47abf8ea819c4865737a09bfe09","target":"record","created_at":"2026-07-05T03:26:12Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"0b9f63af3b244108f73b79707bd98a0cd5cb941e44d61a3236ca185135f53f83","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.MS","submitted_at":"2019-12-16T20:45:42Z","title_canon_sha256":"81a263ba8da469d474132c1c5ff8f31908ac7c3043322d4a0d41e512f3bc321e"},"schema_version":"1.0","source":{"id":"1912.07696","kind":"arxiv","version":2}},"canonical_sha256":"ef6a68ca810771cde97c05e06e43038603f99cac58772a4fbda893f30018e432","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"ef6a68ca810771cde97c05e06e43038603f99cac58772a4fbda893f30018e432","first_computed_at":"2026-07-05T03:26:12.308721Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T03:26:12.308721Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"P/f5GuOe8Ce041ScCLedpEcfxDc9u2kJmspW3Okladp8o48Wflib/QB4LCaqBfXhh3/itMzbhV6vzxfE79WyDw==","signature_status":"signed_v1","signed_at":"2026-07-05T03:26:12.309158Z","signed_message":"canonical_sha256_bytes"},"source_id":"1912.07696","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:77074c6ad8d13271e31889eff30021417e55f47abf8ea819c4865737a09bfe09","sha256:4ba3107c87f9fa78d77933f3fe50138f5d4389349fd57775dbf336e1b2b25872"],"state_sha256":"12d12e785c2c9742b7c447f2ce92bbe3d56abfb3c2deaf09d09fe1039fd10dde"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"hetp5B0K5DVmBLUugQeqgV48FGpCxDPNYTQs1GwvhM71IUlZnlor0nb+2QnTX25hkPj1Q4IKAqrlFcc7eXaDCA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-01T08:00:17.818166Z","bundle_sha256":"958a60ed71e099e091dcd7314df36c3e17a97b1db50aeb8fdd719f019d2f0c32"}}