Math: Complex: Calculate complex phase angle with sofm_atan2() by singalsu · Pull Request #10629 · thesofproject/sof

singalsu · 2026-03-17T16:38:22Z

No description provided.

Copilot

Pull request overview

This PR adds a fixed-point sofm_atan2_32b() implementation (Q1.31 inputs → Q3.29 radians) and switches complex-to-polar phase calculation to use it, along with new unit-test vectors and build integration.

Changes:

Add src/math/atan2.c implementing sofm_atan2_32b() via a Remez polynomial approximation.
Update sofm_icomplex32_to_polar() to compute phase using sofm_atan2_32b() instead of acos_fixed_32b().
Add and wire up atan2 unit tests + generated tables; add Q_CONVERT_QTOD() for double-based comparisons in tests.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
test/ztest/unit/math/basic/trigonometry/trig_test.c	Adds `sofm_atan2_32b()` unit test using generated vectors.
test/ztest/unit/math/basic/trigonometry/atan2_tables.m	Octave/MATLAB script to generate fixed-point test vectors/header.
test/ztest/unit/math/basic/trigonometry/atan2_tables.h	Generated test vectors for atan2 validation.
test/ztest/unit/math/basic/trigonometry/CMakeLists.txt	Links `src/math/atan2.c` into trig unit-test build.
test/ztest/unit/math/basic/complex/test_complex_polar.c	Tightens angle tolerance to match improved phase calculation.
test/ztest/unit/math/basic/complex/CMakeLists.txt	Links `src/math/atan2.c` into complex unit-test build.
src/math/complex.c	Switches polar angle computation to `sofm_atan2_32b()`.
src/math/atan2.c	New implementation of fixed-point 4-quadrant atan2.
src/math/Kconfig	Adds `MATH_ATAN2` config and ensures `MATH_COMPLEX` selects it.
src/math/CMakeLists.txt	Conditionally builds `atan2.c` under `CONFIG_MATH_ATAN2`.
src/include/sof/math/trig.h	Declares `sofm_atan2_32b()` and documents it (needs consistency fixes).
src/include/sof/audio/format.h	Adds `Q_CONVERT_QTOD()` macro used by tests.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

test/ztest/unit/math/basic/trigonometry/trig_test.c

src/include/sof/math/trig.h

src/math/Kconfig

Copilot

Pull request overview

Adds a fixed-point four-quadrant atan2 implementation and switches complex polar conversion to use it (instead of acos-based reconstruction), with accompanying unit tests and build/config wiring.

Changes:

Introduce sofm_atan2_32b() (Q1.31 inputs → Q3.29 radians output) behind CONFIG_MATH_ATAN2.
Update sofm_icomplex32_to_polar() to compute phase via sofm_atan2_32b(imag, real).
Add Ztest coverage for sofm_atan2_32b() plus generated test vectors/tables.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
test/ztest/unit/math/basic/trigonometry/trig_test.c	Adds `sofm_atan2_32b()` unit test using generated vectors.
test/ztest/unit/math/basic/trigonometry/atan2_tables.m	Adds Octave/MATLAB script to generate atan2 test vectors header.
test/ztest/unit/math/basic/trigonometry/atan2_tables.h	Adds generated Q31 input vectors and Q29 reference angles.
test/ztest/unit/math/basic/trigonometry/CMakeLists.txt	Links `atan2.c` into trigonometry unit test build.
test/ztest/unit/math/basic/complex/test_complex_polar.c	Tightens angle tolerance and adjusts test info prints.
test/ztest/unit/math/basic/complex/CMakeLists.txt	Links `atan2.c` into complex unit test build.
src/math/complex.c	Switches polar angle computation to `sofm_atan2_32b()`.
src/math/atan2.c	New polynomial-based atan2 implementation + exported symbol.
src/math/Kconfig	Adds `MATH_ATAN2` option; wires complex math to select needed deps.
src/math/CMakeLists.txt	Builds `atan2.c` when `CONFIG_MATH_ATAN2` is enabled.
src/include/sof/math/trig.h	Declares `sofm_atan2_32b()` and documents it.
src/include/sof/audio/format.h	Adds `Q_CONVERT_QTOD()` helper macro for tests/diagnostics.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

singalsu · 2026-03-20T10:37:25Z

test/ztest/unit/math/basic/trigonometry/trig_test.c

+	double delta_max = 0.0;
+	int32_t result_q29_max = 0;
+	int32_t result_q29;
+	int i_max = -1;
+	int i;


singalsu · 2026-03-20T10:48:28Z

test/ztest/unit/math/basic/trigonometry/trig_test.c

+		zassert_true(delta <= CMP_TOLERANCE_ATAN2,
+			     "sofm_atan2 failed for input %d: (%d, %d) result %d",
+			     i, atan2_test_y[i], atan2_test_x[i], result_q29);


singalsu · 2026-03-20T10:31:32Z

src/include/sof/math/trig.h

+ *   atan(z) = z * (C0 + z^2 * (C1 + z^2 * (C2 + z^2 * C3)))
+ * with Remez minimax coefficients on [0, 1].


Yep, that was still missing from polynomial order increase for sufficient precision.

singalsu · 2026-03-20T10:35:14Z

test/ztest/unit/math/basic/trigonometry/atan2_tables.m

+# SPDX-License-Identifier: BSD-3-Clause
+#
+# Copyright(c) 2026 Intel Corporation.


Yep, good to change. Matlab would error with # - comment, while Octave accepts it.

lgirdwood

Can you resolve the copilot opens. Thanks !

This patch adds the four quadrant arctan function version. It is useful for fast computation of phase angle -pi to +pi in radians from a complex number (real, imaginary) value. The approximation uses a 9th order polynomial that is implemented with Horner's rule evaluation. Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

The usage of Q_CONVERT_QTOF() causes build issue with llvm toolchain when assigned to a double type in ztest code: error: implicit conversion increases floating-point precision: 'float' to 'double' [-Werror,-Wdouble-promotion] Since a double is needed to fully match the accuracy of 32 bit fraction, a new macro Q_CONVERT_QTOD() is added for the purpose. Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

Copilot

Pull request overview

Adds a fixed-point four-quadrant atan2 implementation and switches complex phase-angle calculation to use it, with accompanying unit tests and build/config wiring.

Changes:

Introduces sofm_atan2_32b() (Q1.31 inputs → Q3.29 radians output) implemented via a degree-9 minimax polynomial.
Updates complex-to-polar conversion to compute angle via sofm_atan2_32b() instead of acos-based logic.
Adds table-driven unit tests and supporting generated reference tables; wires atan2.c into relevant test/build targets and Kconfig/CMake.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
test/ztest/unit/math/basic/trigonometry/trig_test.c	Adds `sofm_atan2_32b()` unit test using generated vectors.
test/ztest/unit/math/basic/trigonometry/atan2_tables.m	MATLAB/Octave script to generate atan2 test vectors and references.
test/ztest/unit/math/basic/trigonometry/atan2_tables.h	Generated test vectors/reference angles for atan2 test.
test/ztest/unit/math/basic/trigonometry/CMakeLists.txt	Links `src/math/atan2.c` into trigonometry unit test app.
test/ztest/unit/math/basic/complex/test_complex_polar.c	Tightens angle tolerance and adjusts info prints.
test/ztest/unit/math/basic/complex/CMakeLists.txt	Links `src/math/atan2.c` into complex unit test app.
src/math/complex.c	Uses `sofm_atan2_32b()` for phase angle in `sofm_icomplex32_to_polar()`.
src/math/atan2.c	New implementation of `sofm_atan2_32b()` polynomial atan2 with quadrant mapping.
src/math/Kconfig	Adds `MATH_ATAN2` option; ensures `MATH_COMPLEX` selects required deps.
src/math/CMakeLists.txt	Builds `atan2.c` when `CONFIG_MATH_ATAN2` is enabled.
src/include/sof/math/trig.h	Declares `sofm_atan2_32b()` and documents polynomial form/error.
src/include/sof/audio/format.h	Adds `Q_CONVERT_QTOD()` macro for Q-format to double conversion.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Copilot · 2026-03-20T13:00:50Z

test/ztest/unit/math/basic/trigonometry/trig_test.c

+			i_max = i;
+		}
+		zassert_true(delta <= CMP_TOLERANCE_ATAN2,
+			     "sofm_atan2 failed for input %d: (%d, %d) result %d, expected %d",


The assertion failure message says "sofm_atan2 failed" but the function under test is sofm_atan2_32b(). Updating the message to the correct function name will make failures easier to interpret (especially when multiple atan/atan2 implementations exist).

Suggested change

"sofm_atan2 failed for input %d: (%d, %d) result %d, expected %d",

"sofm_atan2_32b failed for input %d: (%d, %d) result %d, expected %d",

Copilot · 2026-03-20T13:00:50Z

test/ztest/unit/math/basic/trigonometry/trig_test.c

+	for (i = 0; i < ATAN2_TEST_TABLE_SIZE; ++i) {
+		result_q29 = sofm_atan2_32b(atan2_test_y[i], atan2_test_x[i]);
+		result = Q_CONVERT_QTOD(result_q29, 29);
+		reference = Q_CONVERT_QTOD(atan2_test_ref[i], 29);
+		delta = fabs(reference - result);


The test_atan2 coverage currently relies entirely on the generated random table. That table does not include key edge cases like the origin (0,0) and axis-aligned inputs where x == 0 or y == 0, so the function's explicit origin handling and quadrant/axis boundary mapping aren’t exercised. Consider adding a few explicit zasserts for these cases (and expected ±pi/2, 0, ±pi) alongside the table-driven loop.

OK, done in tables data generate script with some forced x or y values in begin.

This patch adds the test for the function. The input values table for atan are Q1.31 (x, y) pair numbers and reference angle values in Q3.29 radians. The table is computed with the double precision atan2() function in Octave and converted to fractional integers. See script atan2_tables.m. Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

This patch updates the phase angle calculation in function sofm_icomple32_to_polar() with more efficient sofm_atan2() function. Calculate of angle with arctan function avoids the 64 bit divide in the previous arccos function based calculation. In 48 kHz stereo STFT processing with 1024 size FFT and hop of 256 this change saves about 14 MCPS in MTL platform (204 MCPS to 190 MCPS). Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

The atan2() function in sofm_ipolar32_to_complex() helped to increase accuracy, so the tolerance for error could be decreased to about 0.001 degrees (2.0e-5 radians). Also the print format for achieved accuracy is improved for nicer appearance. Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

singalsu force-pushed the math_add_atan2 branch from ec549e9 to 9971505 Compare March 18, 2026 10:15

singalsu marked this pull request as ready for review March 18, 2026 10:25

singalsu requested review from dbaluta, kv2019i, lbetlej, lgirdwood, mmaka1 and plbossart as code owners March 18, 2026 10:26

Copilot AI review requested due to automatic review settings March 18, 2026 10:26

Copilot started reviewing on behalf of singalsu March 18, 2026 10:26 View session

Copilot AI reviewed Mar 18, 2026

View reviewed changes

test/ztest/unit/math/basic/trigonometry/trig_test.c Outdated Show resolved Hide resolved

src/include/sof/math/trig.h Outdated Show resolved Hide resolved

src/math/Kconfig Outdated Show resolved Hide resolved

singalsu force-pushed the math_add_atan2 branch from 9971505 to aecc9d3 Compare March 18, 2026 10:49

singalsu requested a review from Copilot March 18, 2026 10:50

Copilot started reviewing on behalf of singalsu March 18, 2026 10:53 View session

Copilot AI reviewed Mar 18, 2026

View reviewed changes

lgirdwood approved these changes Mar 19, 2026

View reviewed changes

singalsu added 2 commits March 20, 2026 12:32

singalsu force-pushed the math_add_atan2 branch from aecc9d3 to ce0a725 Compare March 20, 2026 11:10

singalsu requested a review from Copilot March 20, 2026 12:56

Copilot started reviewing on behalf of singalsu March 20, 2026 12:56 View session

Copilot AI reviewed Mar 20, 2026

View reviewed changes

singalsu added 3 commits March 20, 2026 15:38

singalsu force-pushed the math_add_atan2 branch from ce0a725 to e0bf5df Compare March 20, 2026 13:42

singalsu requested a review from Copilot March 20, 2026 13:43

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Math: Complex: Calculate complex phase angle with sofm_atan2()#10629

Math: Complex: Calculate complex phase angle with sofm_atan2()#10629
singalsu wants to merge 5 commits intothesofproject:mainfrom
singalsu:math_add_atan2

singalsu commented Mar 17, 2026

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Uh oh!

singalsu Mar 20, 2026

Uh oh!

singalsu Mar 20, 2026

Uh oh!

singalsu Mar 20, 2026

Uh oh!

singalsu Mar 20, 2026

Uh oh!

lgirdwood left a comment

Uh oh!

Copilot AI left a comment

Uh oh!

Copilot AI Mar 20, 2026

Uh oh!

Copilot AI Mar 20, 2026

Uh oh!

singalsu Mar 20, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

		* atan(z) = z * (C0 + z^2 * (C1 + z^2 * (C2 + z^2 * C3)))
		* with Remez minimax coefficients on [0, 1].

	"sofm_atan2 failed for input %d: (%d, %d) result %d, expected %d",
	"sofm_atan2_32b failed for input %d: (%d, %d) result %d, expected %d",

Conversation

singalsu commented Mar 17, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

singalsu Mar 20, 2026

Choose a reason for hiding this comment

Uh oh!

singalsu Mar 20, 2026

Choose a reason for hiding this comment

Uh oh!

singalsu Mar 20, 2026

Choose a reason for hiding this comment

Uh oh!

singalsu Mar 20, 2026

Choose a reason for hiding this comment

Uh oh!

lgirdwood left a comment

Choose a reason for hiding this comment

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Copilot AI Mar 20, 2026

Choose a reason for hiding this comment

Uh oh!

Copilot AI Mar 20, 2026

Choose a reason for hiding this comment

Uh oh!

singalsu Mar 20, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants