tbensonatl · 2026-08-23T18:10:41Z

Add an experimental operator to apply bulk motion compensation to frequency domain SAR phase history history. It applies a frequency-dependent phase ramp to each pulse, referencing its phase to the specified per-pulse reference range.

Add a --bulk-mocomp option to the sarbp example that applies bulk mocomp based on the reference ranges contained in the CPHD file (or in the sarbp input file, which is typically generated from a CPHD). Applying mocomp to data that has already been mocomped will effectively reference the phase to the wrong point (i.e., mocomp is not idempotent and applying it multiple times will generate errors). Most CPHD files are already mocomped, so this option is for special cases where the data is not mocomped or the sarbp input file was generated with non-mocomped data.

Add an experimental operator to apply bulk motion compensation to frequency domain SAR phase history history. It applies a frequency-dependent phase ramp to each pulse, referencing its phase to the specified per-pulse reference range. Add a --bulk-mocomp option to the sarbp example that applies bulk mocomp based on the reference ranges contained in the CPHD file (or in the sarbp input file, which is typically generated from a CPHD). Applying mocomp to data that has already been mocomped will effectively reference the phase to the wrong point (i.e., mocomp is not idempotent and applying it multiple times will generate errors). Most CPHD files are already mocomped, so this option is for special cases where the data is not mocomped or the sarbp input file was generated with non-mocomped data. Signed-off-by: Thomas Benson <tbenson@nvidia.com>

copy-pr-bot · 2026-08-23T18:10:45Z

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greptile-apps · 2026-08-23T18:15:46Z

Greptile Summary

The PR adds an experimental lazy operator for frequency-domain SAR bulk motion compensation and integrates it into the SAR backprojection example.

Adds host, CUDA, and CUDA JIT-compatible phase-ramp evaluation with float and double range arithmetic.
Adds a --bulk-mocomp example path supporting complex and scaled-int16 FX input, block processing, windowing, and FloatFloat backprojection.
Adds API documentation, executor compatibility information, constants cleanup, and operator and SAR integration tests.

Confidence Score: 5/5

The PR appears safe to merge because no blocking failure remains.

No blocking failure remains.

Important Files Changed

Filename	Overview
include/matx/operators/sar_bulk_mocomp.h	Implements the lazy bulk-motion-compensation expression, parameter and shape validation, phase arithmetic, and CUDA JIT capability propagation.
examples/sarbp/sarbp.cu	Integrates optional bulk motion compensation into FX preprocessing, including int16 conversion, windowing, block staging, timing, and FloatFloat handling.
test/00_operators/sar_bulk_mocomp_test.cu	Tests phase correction, odd and even frequency grids, batched reference changes, composed range expressions, precision behavior, and validation.
test/00_transform/SarBp.cu	Extends SAR backprojection validation to cover the new motion-compensation workflow and coordinated phase-reference behavior.
include/matx/kernels/sar_bp.cuh	Moves the speed-of-light constant to the shared constants API while preserving the established SAR phase-LUT calculation.
docs_input/api/signalimage/radar/sar_bulk_mocomp.rst	Documents the operator’s tensor contract, phase equation, precision behavior, restrictions, and executor support.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart LR
    A[FX phase-history input] --> B{Input encoding}
    B -->|Complex| C[FX tensor]
    B -->|Int16 IQ| D[Scale and convert to complex]
    D --> C
    C --> E[Optional range window]
    R[Per-pulse range to MCP] --> F[Bulk motion compensation]
    P[Center frequency, sample spacing, sign] --> F
    E --> F
    F --> G[Range compression and upsampling]
    G --> H[SAR backprojection]
    R --> H
    H --> I[Focused SAR image]

_{Reviews (4): Last reviewed commit: "Run previously JIT-only mocomp tests thr..." | Re-trigger Greptile}

tbensonatl · 2026-08-23T18:16:20Z

/build

When the ranges are double-precision and the FX data is complex<float>, add a fast-path that uses double-precision for range reduction and then uses sincospif() rather than sincospi() for the complex exponential. Thus, the complex exponential itself is reduced precision relative to the double-precision version, but ultimately we will narrow to complex<float> in the stored FX data, so loss is minimal in applying sincospif() on a reduced input argument. Signed-off-by: Thomas Benson <tbenson@nvidia.com>

tbensonatl · 2026-08-23T21:10:45Z

/build

coveralls · 2026-08-24T04:05:03Z

Coverage is 93.302% — tbenson/add-sar-bulk 8000 -mocomp-operator into main. No base build found for main.

Include an example from the unit test suite in the documentation rather than an inlined example that is never executed. Signed-off-by: Thomas Benson <tbenson@nvidia.com>

Signed-off-by: Thomas Benson <tbenson@nvidia.com>

tbensonatl · 2026-08-24T17:50:28Z

/build

tbensonatl self-assigned this Aug 23, 2026

tbensonatl requested a review from cliffburdick August 23, 2026 18:16

Move documentation example from .rst to unit test

5e48446

Include an example from the unit test suite in the documentation rather than an inlined example that is never executed. Signed-off-by: Thomas Benson <tbenson@nvidia.com>

cliffburdick reviewed Aug 24, 2026

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Comment thread examples/sarbp/sarbp.cu

cliffburdick reviewed Aug 24, 2026

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Comment thread test/00_operators/sar_bulk_mocomp_test.cu Outdated

cliffburdick approved these changes Aug 24, 2026

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Run previously JIT-only mocomp tests through all executors

cfc1556

Signed-off-by: Thomas Benson <tbenson@nvidia.com>

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Add bulk SAR mocomp operator - #1230