arc: one clock per arm, absolute-duration clocks with speed-bounded isotonic decode

docs/ARC_CLOCK_CONTRACT.md

@@ -13,7 +13,7 @@ for models, frozen data pools, budgets, retained variants and migration.
 ```yaml
 _target_: egomimic.rldb.zarr.arc_length_tokenizer.TokenizeBimanualArcLengthCartesian
 clock_mode: velocity                 # velocity | duration
-streams: full_separation              # full_separation | translation_rotation
+streams: full_separation              # full_separation | translation_rotation | translation
 resampled_vector_length: 100
 min_distance_unit: 0.42               # meters, per arm
 rotation_distance_unit: 1.7453292519943295  # radians, per arm (100 degrees)
@@ -32,6 +32,7 @@ Geometry always occupies the first 14 columns:
 | --- | --- | --- |
 | full_separation | M × 20 | T-left, T-right, R-left, R-right, G-left, G-right |
 | translation_rotation | M × 18 | T-left, T-right, R-left, R-right |
+| translation | M × 16 | T-left, T-right (rotation and gripper ride the translation supports) |
 
 Each arm and stream spends its own spatial budget. Supports from different
 streams in the same row are not necessarily simultaneous.
@@ -51,9 +52,13 @@ There is no repeated final padding clock.
 - velocity: row zero is seconds; later rows are the distance between emitted
   supports divided by the source interval's seconds. Units are m/s, rad/s,
   and gripper units/s.
-- duration: every row is `log(seconds + 0.001)`, including the initial delay.
-  The codec removes the log exactly once. `duration` does not mean absolute
-  timestamps or raw seconds.
+- duration: every row is the absolute seconds from the chunk anchor to that
+  waypoint (row zero is the start delay). Decoding projects the rows once onto
+  the nearest non-decreasing clock by isotonic regression on the slack above
+  the fastest clock allowed by the 5 m/s translation max speed (no min speed:
+  rotation and gripper ride slow arms), so a backwards pair is averaged and no local
+  error accumulates into later rows. Provenance `timing_layout` is
+  `first_delay_absolute_v1`; velocity keeps `first_delay_incoming_v1`.
 
 Translation distances are Euclidean, rotation distances are SO(3) geodesic,
 and gripper distances are absolute value differences. No velocity smoothing,

egomimic/eval/open_loop_sim.py

@@ -738,7 +738,7 @@ def _cap_arc_video_trajectories(
         for index, steps in enumerate(prefix_lengths):
             rotation_cap = (
                 None
-                if rotation_distance_unit is None
+                if rotation_distance_unit is None or self.streams == "translation"
                 else self.execute_fraction * rotation_distance_unit
             )
             gripper_cap = (

egomimic/hydra_configs/experiment/README.md

@@ -51,11 +51,13 @@ Each task's three entries use exactly the same filters, episode lists and split.
 Baseline geometry is 100 × 14 time-indexed actions.
 
 ARC uses the canonical [clock contract](../../../docs/ARC_CLOCK_CONTRACT.md)
-(repository path `docs/ARC_CLOCK_CONTRACT.md`): velocity or log **interval**
-seconds, first-row start delay, first-moving-stream termination.
-It is not E1 or cumulative absolute seconds. Full separation is the default.
-Use `abc.arc_streams=translation_rotation` for four clocks; token width
-automatically changes from M × 20 to M × 18, including the model and decoder.
+(repository path `docs/ARC_CLOCK_CONTRACT.md`): velocity rates or **absolute**
+seconds from the chunk anchor (decoded by speed-bounded isotonic regression),
+first-row start delay, first-moving-stream termination.
+Full separation is the default. Use `abc.arc_streams=translation_rotation` for
+four clocks (M × 18) or `translation` for one clock per arm (M × 16, rotation and
+gripper ride the translation supports); token width follows automatically,
+including the model and decoder.
 No tokenizer or detokenizer algorithm is changed by this YAML reorganization.
 
 The frozen towel/earbud ARC entries are **new canonical-codec recipes** built

egomimic/hydra_configs/experiment/_shared/clock_settings.yaml

@@ -6,6 +6,11 @@ abc:
   arc_stream_dims:
     full_separation: 20
     translation_rotation: 18
+    translation: 16
+  # Duration rows are absolute seconds from the anchor; velocity rows are incoming rates.
+  arc_timing_layouts:
+    velocity: first_delay_incoming_v1
+    duration: first_delay_absolute_v1
   arc_token_dim: ${abc.arc_stream_dims.${abc.arc_streams}}
   arc_token_rows: ${abc.arc_waypoints}
 run_provenance:
@@ -17,7 +22,7 @@ run_provenance:
     waypoints: ${abc.arc_waypoints}
     clock_mode: ${abc.arc_clock_mode}
     streams: ${abc.arc_streams}
-    timing_layout: first_delay_incoming_v1
+    timing_layout: ${abc.arc_timing_layouts.${abc.arc_clock_mode}}
     hold_window_frames: 400
     gripper_stream_mode: ${oc.select:abc.arc_gripper_stream_mode,events}
     gripper_distance_unit: ${oc.select:abc.arc_gripper_distance,null}

egomimic/hydra_configs/experiment/_shared/frozen_yam_arc.yaml

@@ -89,5 +89,5 @@ evaluator:
   streams: ${abc.arc_streams}
 logger:
   wandb:
-    id: ${name}_s42
+    id: ${name}_s${seed}
     tags: [rl2, hpt300, "${abc.arc_clock_mode}", "${abc.arc_streams}", open_loop, video]

egomimic/hydra_configs/experiment/real/fold_and_stack_towels/arc_dur.yaml

@@ -3,6 +3,6 @@ defaults:
   - /experiment/real/fold_and_stack_towels/arc_vel
   - _self_
 name: fold_and_stack_towels_arc_dur
-description: Frozen since0924plus74 towels HPT300, canonical log-duration ARC M200 D0.33 R100
+description: Frozen since0924plus74 towels HPT300, canonical absolute-duration ARC M200 D0.33 R100
 abc:
   arc_clock_mode: duration

egomimic/hydra_configs/experiment/real/multitask/arc_dur.yaml

@@ -3,7 +3,7 @@ defaults:
   - /experiment/real/multitask/arc_vel
   - _self_
 name: multitask_arc_dur
-description: HPT300 ABC four-task first-delay log-duration ARC
+description: HPT300 ABC four-task first-delay absolute-duration ARC
 abc:
   arc_clock_mode: duration
 logger:

egomimic/hydra_configs/experiment/real/organize_stationary/arc_dur.yaml

@@ -3,6 +3,6 @@ defaults:
   - /experiment/real/organize_stationary/arc_vel
   - _self_
 name: organize_stationary_arc_dur
-description: HPT300 robot + human organize stationery, first-delay log-duration
+description: HPT300 robot + human organize stationery, first-delay absolute duration
 abc:
   arc_clock_mode: duration

egomimic/hydra_configs/experiment/real/wireless_earbuds/arc_dur.yaml

@@ -3,6 +3,6 @@ defaults:
   - /experiment/real/wireless_earbuds/arc_vel
   - _self_
 name: wireless_earbuds_arc_dur
-description: Frozen earbuds HPT300, canonical log-duration ARC M200 D0.33 R100
+description: Frozen earbuds HPT300, canonical absolute-duration ARC M200 D0.33 R100
 abc:
   arc_clock_mode: duration

egomimic/rldb/AGENTS.md

@@ -16,7 +16,9 @@ The root AGENTS.md applies here. Dataset/experiment selection belongs in
 - `zarr/action_chunk_transforms.py`: shared pose, rotation, gripper, interpolation
   and key-routing transforms. Add general transform behavior here.
 - `zarr/arc_length_tokenizer.py`: Cartesian ARC with `clock_mode` velocity or
-  duration and `streams` full_separation (M×20) or translation_rotation (M×18).
+  duration (absolute seconds, speed-bounded isotonic decode) and `streams`
+  full_separation (M×20), translation_rotation (M×18) or translation
+  (M×16, one clock per arm).
   See `docs/ARC_CLOCK_CONTRACT.md`; row zero is a start delay.
 - `zarr/embodiment_resolvers.py`, `zarr/progress_sampler.py`: metadata overrides and
   configurable anchor sampling used by the tempo recipes.