`ler.image_properties.sample_caustic_points_njit`

Symmetry-accelerated source-position sampling for EPL + shear caustics.

This version avoids constructing the full caustic boundary for sampling. It asks cross_section_njit._helper_caustic_epl_shear for only the half-boundary 0 <= theta < pi, rotates only that half-boundary, builds a half-fan cumulative area table, samples from that half, and then flips the sampled point to the antipodal half with probability 1/2.

No parallel=True and no cache=True are used.

Module Contents

Functions

`caustic_points_epl_shear_half`(theta_E, q, phi, gamma, ...)	Return only the rotated half-boundary of the EPL+shear caustic.
`sample_source_from_double_caustic`(theta_E, q, phi, ...)	Sample a single source position from the double caustic region.

Attributes

PI

ler.image_properties.sample_caustic_points_njit.PI[source]

ler.image_properties.sample_caustic_points_njit.caustic_points_epl_shear_half(theta_E, q, phi, gamma, gamma1, gamma2, num_th=500, maginf=-100.0, quad=False)[source]

Return only the rotated half-boundary of the EPL+shear caustic.

The returned points correspond to the first half of the full angular grid, 0 <= theta < pi. The other half is obtained exactly by central inversion, p(theta + pi) = -p(theta). This is intended for area/sampling routines that can exploit central symmetry and therefore do not need the explicit full boundary.

Parameters:

theta_Efloat

Einstein radius.

qfloat

Axis ratio.

phifloat

Position angle of the lens major axis in radians.

gammafloat

EPL slope exponent.

gamma1float

First shear component.

gamma2float

Second shear component.

num_thint

Number of angular samples.

default: 500

maginffloat

Magnification cut threshold.

default: -100.0

quadbool

If True, return the quad (inner) caustic. If False, return the double (outer) caustic.

default: False

Returns:

pos_halfnumpy.ndarray: Shape (2, num_th//2). Rotated source-plane caustic half-boundary.

ler.image_properties.sample_caustic_points_njit.sample_source_from_double_caustic(theta_E, q, phi, gamma, gamma1, gamma2, num_th=500, maginf=-100.0)[source]

Sample a single source position from the double caustic region.

Precomputes the caustic boundary once (the expensive part) and draws one uniform sample via exact fan-triangulation from the origin.