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fix: deferred-simp context manager for Ga.build in curvi_linear_latex (#576) #592

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fix: deferred-simp context manager for Ga.build in curvi_linear_latex (#576) #592

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1ce1340
fix: deferred-simp approach for curvi_linear_latex (#576)
utiberious Apr 3, 2026
49b2e05
fix: deferred-simp context manager for Ga.build in curvi_linear_latex…
utiberious Apr 3, 2026
db3b76f
chore(nb): re-execute LaTeX.ipynb with deferred-simp build approach
utiberious Apr 3, 2026
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87 changes: 67 additions & 20 deletions examples/LaTeX/curvi_linear_latex.py
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Original file line number Diff line number Diff line change
@@ -1,14 +1,40 @@
from __future__ import print_function
import sys
from contextlib import contextmanager

from sympy import symbols,sin,cos,sinh,cosh
from sympy import symbols,sin,cos,sinh,cosh,trigsimp
from galgebra.ga import Ga
from galgebra.metric import Simp
from galgebra.printer import Format, xpdf, Print_Function, Eprint


@contextmanager
def _no_simp_build():
"""Use an identity simplifier during Ga.build, then restore the caller's Simp profile.

``Ga.build(norm=True)`` calls ``Simp.apply`` ~70 times during metric
normalisation. Since SymPy 1.13 (PR #26390) each call traverses every
trig/hyperbolic node via ``.replace(Mul, ...)`` inside ``TR3``/``futrig``,
which is always a no-op for symbolic trig arguments but costs ~25 s per call.

By substituting an identity simplifier for the build phase we skip all ~70
traversals. The callers' ``Simp.modes`` (set by ``main()`` to
``trigsimp(method='old')``) remain active for the output expressions, so
``_sympystr`` still simplifies each printed result once when formatting.
"""
orig = Simp.modes[:]
Simp.profile([lambda e: e]) # identity — no simplification during build
try:
yield
finally:
Simp.profile(orig)


def derivatives_in_spherical_coordinates():
#Print_Function()
coords = (r,th,phi) = symbols('r theta phi', real=True)
(sp3d,er,eth,ephi) = Ga.build('e_r e_theta e_phi',g=[1,r**2,r**2*sin(th)**2],coords=coords)
with _no_simp_build():
(sp3d,er,eth,ephi) = Ga.build('e_r e_theta e_phi',g=[1,r**2,r**2*sin(th)**2],coords=coords)
grad = sp3d.grad

f = sp3d.mv('f','scalar',f=True)
Expand Down Expand Up @@ -39,7 +65,8 @@ def derivatives_in_spherical_coordinates():
def derivatives_in_paraboloidal_coordinates():
#Print_Function()
coords = (u,v,phi) = symbols('u v phi', real=True)
(par3d,er,eth,ephi) = Ga.build('e_u e_v e_phi',X=[u*v*cos(phi),u*v*sin(phi),(u**2-v**2)/2],coords=coords,norm=True)
with _no_simp_build():
(par3d,er,eth,ephi) = Ga.build('e_u e_v e_phi',X=[u*v*cos(phi),u*v*sin(phi),(u**2-v**2)/2],coords=coords,norm=True)
grad = par3d.grad

f = par3d.mv('f','scalar',f=True)
Expand All @@ -64,7 +91,8 @@ def derivatives_in_elliptic_cylindrical_coordinates():
#Print_Function()
a = symbols('a', real=True)
coords = (u,v,z) = symbols('u v z', real=True)
(elip3d,er,eth,ephi) = Ga.build('e_u e_v e_z',X=[a*cosh(u)*cos(v),a*sinh(u)*sin(v),z],coords=coords,norm=True)
with _no_simp_build():
(elip3d,er,eth,ephi) = Ga.build('e_u e_v e_z',X=[a*cosh(u)*cos(v),a*sinh(u)*sin(v),z],coords=coords,norm=True)
grad = elip3d.grad

f = elip3d.mv('f','scalar',f=True)
Expand All @@ -88,8 +116,9 @@ def derivatives_in_prolate_spheroidal_coordinates():
#Print_Function()
a = symbols('a', real=True)
coords = (xi,eta,phi) = symbols('xi eta phi', real=True)
(ps3d,er,eth,ephi) = Ga.build('e_xi e_eta e_phi',X=[a*sinh(xi)*sin(eta)*cos(phi),a*sinh(xi)*sin(eta)*sin(phi),
a*cosh(xi)*cos(eta)],coords=coords,norm=True)
with _no_simp_build():
(ps3d,er,eth,ephi) = Ga.build('e_xi e_eta e_phi',X=[a*sinh(xi)*sin(eta)*cos(phi),a*sinh(xi)*sin(eta)*sin(phi),
a*cosh(xi)*cos(eta)],coords=coords,norm=True)
grad = ps3d.grad

f = ps3d.mv('f','scalar',f=True)
Expand All @@ -113,8 +142,9 @@ def derivatives_in_oblate_spheroidal_coordinates():
Print_Function()
a = symbols('a', real=True)
coords = (xi,eta,phi) = symbols('xi eta phi', real=True)
(os3d,er,eth,ephi) = Ga.build('e_xi e_eta e_phi',X=[a*cosh(xi)*cos(eta)*cos(phi),a*cosh(xi)*cos(eta)*sin(phi),
a*sinh(xi)*sin(eta)],coords=coords,norm=True)
with _no_simp_build():
(os3d,er,eth,ephi) = Ga.build('e_xi e_eta e_phi',X=[a*cosh(xi)*cos(eta)*cos(phi),a*cosh(xi)*cos(eta)*sin(phi),
a*sinh(xi)*sin(eta)],coords=coords,norm=True)
grad = os3d.grad

f = os3d.mv('f','scalar',f=True)
Expand All @@ -136,7 +166,8 @@ def derivatives_in_bipolar_coordinates():
Print_Function()
a = symbols('a', real=True)
coords = (u,v,z) = symbols('u v z', real=True)
(bp3d,eu,ev,ez) = Ga.build('e_u e_v e_z',X=[a*sinh(v)/(cosh(v)-cos(u)),a*sin(u)/(cosh(v)-cos(u)),z],coords=coords,norm=True)
with _no_simp_build():
(bp3d,eu,ev,ez) = Ga.build('e_u e_v e_z',X=[a*sinh(v)/(cosh(v)-cos(u)),a*sin(u)/(cosh(v)-cos(u)),z],coords=coords,norm=True)
grad = bp3d.grad

f = bp3d.mv('f','scalar',f=True)
Expand All @@ -158,9 +189,10 @@ def derivatives_in_toroidal_coordinates():
Print_Function()
a = symbols('a', real=True)
coords = (u,v,phi) = symbols('u v phi', real=True)
(t3d,eu,ev,ephi) = Ga.build('e_u e_v e_phi',X=[a*sinh(v)*cos(phi)/(cosh(v)-cos(u)),
a*sinh(v)*sin(phi)/(cosh(v)-cos(u)),
a*sin(u)/(cosh(v)-cos(u))],coords=coords,norm=True)
with _no_simp_build():
(t3d,eu,ev,ephi) = Ga.build('e_u e_v e_phi',X=[a*sinh(v)*cos(phi)/(cosh(v)-cos(u)),
a*sinh(v)*sin(phi)/(cosh(v)-cos(u)),
a*sin(u)/(cosh(v)-cos(u))],coords=coords,norm=True)
grad = t3d.grad

f = t3d.mv('f','scalar',f=True)
Expand All @@ -181,14 +213,29 @@ def derivatives_in_toroidal_coordinates():
def main():
#Eprint()
Format()
derivatives_in_spherical_coordinates()
derivatives_in_paraboloidal_coordinates()
# FIXME This takes ~600 seconds
# derivatives_in_elliptic_cylindrical_coordinates()
derivatives_in_prolate_spheroidal_coordinates()
#derivatives_in_oblate_spheroidal_coordinates()
#derivatives_in_bipolar_coordinates()
#derivatives_in_toroidal_coordinates()

# SymPy >= 1.13 (PR #26390) added a slow O(N*M) traversal inside
# sympy.simplify.fu that causes timeouts on curvilinear coordinate
# expressions. Use trigsimp(method='old') via Simp.profile to avoid
# that code path entirely for this example.
#
# _no_simp_build() inside each function further avoids ~70 redundant
# Simp.apply calls during Ga.build by substituting an identity simplifier
# for the build phase only. The trigsimp(method='old') profile below
# then applies once per output expression via _sympystr at print time.
orig_modes = Simp.modes[:]
Simp.profile([lambda e: trigsimp(e, method='old')])
try:
derivatives_in_spherical_coordinates()
derivatives_in_paraboloidal_coordinates()
# FIXME This takes ~600 seconds
# derivatives_in_elliptic_cylindrical_coordinates()
derivatives_in_prolate_spheroidal_coordinates()
#derivatives_in_oblate_spheroidal_coordinates()
#derivatives_in_bipolar_coordinates()
#derivatives_in_toroidal_coordinates()
finally:
Simp.profile(orig_modes)

# xpdf()
xpdf(pdfprog=None)
Expand Down
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