Find derivative recurrences from PDE (via parametric derivative taking) by hirish99 · Pull Request #204 · inducer/sumpy

hirish99 · 2024-07-10T19:43:50Z

Revised version of #202, using parametric approach to compute recurrences for derivatives.

hirish99 · 2024-07-19T00:24:06Z

Requesting review @inducer

hirish99 · 2024-07-24T02:59:03Z

Request review @inducer

hirish99 · 2024-10-28T19:32:47Z

Request review

sumpy/recurrence.py

inducer · 2024-10-28T20:19:56Z

sumpy/recurrence.py

+    # Sort terms and create idx_l
+    idx_l = []
+    for i in range(len(terms)):
+        tms = list(terms[i].atoms(sp.Number))


Carefully destructure term for correctness.

sumpy/recurrence.py

inducer · 2024-10-28T20:46:46Z

sumpy/test/test_recurrence.py

@@ -0,0 +1,83 @@
+from sumpy.expansion.diff_op import (


Add license header.

sumpy/recurrence.py

inducer · 2024-11-04T21:22:47Z

test/test_recurrenceqbx.py

+    return result_qbx
+
+
+def _qbx_lp_laplace_general(sources, targets, centers, radius, strengths, order):


Unify with the Helmholtz case?

inducer · 2024-11-04T21:23:11Z

test/test_recurrenceqbx.py

+    return sources, centers, normals, density, h, radius
+
+
+def test_recurrence_laplace_2d_ellipse():


Unify with Helmholtz case?

test/test_recurrence.py

test/test_recurrenceqbx.py

test/test_recurrence.py

inducer · 2024-11-04T21:31:47Z

test/test_recurrence.py

+    w = make_identity_diff_op(2)
+    helmholtz2d = laplacian(w) + w
+    _, _, r = get_processed_and_shifted_recurrence(helmholtz2d)
+
+    n = sp.symbols("n")
+    s = sp.Function("s")
+
+    var = _make_sympy_vec("x", 2)
+    var_t = _make_sympy_vec("t", 2)
+    abs_dist = sp.sqrt((var[0]-var_t[0])**2 +
+                       (var[1]-var_t[1])**2)
+    k = 1
+    g_x_y = (1j/4) * hankel1(0, k * abs_dist)


Get from a Kernel object? (Here and elsewhere.)

inducer · 2024-11-04T21:41:06Z

sumpy/recurrenceqbx.py

+
+
+# ================ Recurrence LP Eval =================
+def recurrence_qbx_lp(sources, centers, normals, strengths, radius, pde, g_x_y,


Use a Kernel as an argument?

inducer · 2024-11-12T20:27:08Z

sumpy/recurrence.py

+def shift_recurrence(r: sp.Expr) -> sp.Expr:
+    r"""
+    A function that "shifts" the recurrence so it's center is placed
+    at the origin and source is the input for the recurrence generated.
+
+    :arg recurrence: a recurrence relation in :math:`s(n)`
+    """


Explain better.

sumpy/recurrenceqbx.py

inducer · 2024-11-12T20:28:37Z

sumpy/recurrenceqbx.py

+r"""
+With the functionality in this module, we aim to compute layer potentials
+using a recurrence for one-dimensional derivatives of the corresponding
+Green's function. See recurrence.py.


Suggested change

Green's function. See recurrence.py.

Green's function. See :mod:`sumpy.recurrence`.

inducer · 2024-11-12T20:28:56Z

sumpy/recurrenceqbx.py

Add to docs.

inducer · 2024-11-12T20:29:14Z

sumpy/recurrenceqbx.py

recurrence_qbx?

sumpy/recurrenceqbx.py

inducer · 2024-11-12T20:30:06Z

sumpy/recurrenceqbx.py

+
+.. autofunction:: recurrence_qbx_lp
+"""
+from __future__ import annotations  # noqa: I001


hirish99 · 2025-01-03T00:31:09Z

Plots updated in plot_taylor_recurrence and plot_normal_recurrence

Adds recurrence-based QBX layer potential evaluation with on-axis and off-axis computation support for Laplace and Helmholtz kernels in 2D and 3D.

- Add pyright ignore comments for sympy typing issues in recurrence.py and recurrence_qbx.py (sum() return type, .subs() return type, ObjectArray1D vs ndarray) - Broaden parameter types from sp.Expr to sp.Basic where .subs() results are passed - Remove personal plotting code from test files - Remove tracked experimental files (pgf, png, svg, ipynb) - Update .gitignore to exclude *.ipynb, *.pgf, output.png, qbxrecurrence.svg

- Add pyright ignore comments for reportMissingImports, reportCallIssue, reportArgumentType, reportAttributeAccessIssue, and reportIndexIssue in test files (meshmode/pytential are optional deps without full stubs) - Fix RST formatting in recurrence.py docstrings (indentation, bullet lists) - Fix wrong function name in autofunction directive - Fix typo in class reference (LinearSystemPDEOperator -> LinearPDESystemOperator)

basedpyright reports reportMissingImports on the 'from' line, not on the inner item line where ruff moved the comment.

Rename functions to match paper (arXiv:2509.03687) terminology: - get_on_axis_recurrence -> get_large_x1_recurrence - get_off_axis_recurrence -> get_small_x1_recurrence - get_off_axis_expression -> get_small_x1_expansion Add documentation with diagram and usage examples for computing derivatives in both regimes. Add recurrence_qbx to docs.

…rer notation

- Fix recurrence_qbx_lp docstring: evaluation is at target points (center + radius * normal), not at expansion centers. - Merge baseline with upstream/main to cover CI-specific diagnostics for pre-existing files while adding entries for new recurrence files.

inducer changed the title ~~Add functionality to find derivative recurrences from PDE~~ Add functionality to find derivative recurrences from PDE (via parametric derivative taking) Jul 15, 2024

inducer mentioned this pull request Jul 15, 2024

Add functionality to find derivative recurrences from PDE (via Taylor) #202

Closed

inducer force-pushed the parametric_recurrence branch from f77f639 to e363248 Compare July 29, 2024 21:06

inducer changed the title ~~Add functionality to find derivative recurrences from PDE (via parametric derivative taking)~~ Find derivative recurrences from PDE (via parametric derivative taking) Aug 5, 2024

inducer reviewed Oct 28, 2024

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inducer reviewed Nov 4, 2024

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inducer reviewed Nov 12, 2024

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hirish99 added 2 commits February 9, 2026 16:40

Add parametric recurrence QBX implementation

d174225

Adds recurrence-based QBX layer potential evaluation with on-axis and off-axis computation support for Laplace and Helmholtz kernels in 2D and 3D.

hirish99 force-pushed the parametric_recurrence branch from 8f58772 to 03e0eeb Compare February 9, 2026 23:02

hirish99 added 6 commits February 9, 2026 17:49

Move pyright ignore to from-line for parenthesized imports

6ca0d90

basedpyright reports reportMissingImports on the 'from' line, not on the inner item line where ruff moved the comment.

Improve recurrence module documentation with LaTeX equations and clea…

fb93224

…rer notation

Update basedpyright baseline

f457a6b

		return result_qbx


		def _qbx_lp_laplace_general(sources, targets, centers, radius, strengths, order):

		return sources, centers, normals, density, h, radius


		def test_recurrence_laplace_2d_ellipse():



		# ================ Recurrence LP Eval =================
		def recurrence_qbx_lp(sources, centers, normals, strengths, radius, pde, g_x_y,

	Green's function. See recurrence.py.
	Green's function. See :mod:`sumpy.recurrence`.

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hirish99 commented Jan 3, 2025

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