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Table 2.

Time comparison for one-step sampling in the joint modeling.

Process Type of implementation Runtime (CPU) Runtime (GPU)
Previous work Extended Image Suyu et al. (2006) in C 2 s
MGE 1D fit (1 profile; total) Shajib (2019) in NumPy ∼2 × 10−4 s; 1  ×  10−3 s
MGE 1D fit (1 profile; total) mge.fit_1D(linear = True) in NumPy1 ∼3 × 10−3 s; 0.02 s
v r 2 ¯ $ \overline{v_r^2} $, v θ 2 ¯ $ \overline{v_\theta^2} $, v ϕ 2 ¯ $ \overline{v_\phi^2} $ calculations Integral solver (adaptive) in NumPy 2 13 s
v rms pre $ {\boldsymbol{v}}_{\mathbf{rms}}^{\mathbf{pre}} $ calculation jam.axi.proj in NumPy2 14 s

This paper Extended image Follows Suyu et al. (2006) in JAX 10 s 0.21 s
MGE 1D fit (1 profile; total) Follows Shajib (2019) in JAX ∼0.13 s; 0.52 s ∼2 × 10−4 s; 6 × 10−4 s
v r 2 ¯ $ \overline{v_r^2} $, v θ 2 ¯ $ \overline{v_\theta^2} $, v ϕ 2 ¯ $ \overline{v_\phi^2} $ calculations Integral solver (non-adaptive) in JAX 118 s 0.32 s
v rms pre $ {\boldsymbol{v}}_{\mathbf{rms}}^{\mathbf{pre}} $ calculation jam.axi.proj in JAX 119 s 0.33 s

Notes.

The joint modeling is based on a composite mass model with a 64 × 64 source grid (see Sect. 3.3 for the adopted profiles). The computations were performed on a 2.10 GHz CPU and an NVIDIA A100 GPU. This table presents the runtime for the MGE 1D fit for a single mass or light profile (1 profile) and for the decomposition of all mass and light profiles in the modeling (total). The comparison of all MGE 1D fits was conducted using the same number of 21 Gaussians and the same number of log radii. The running time of the integral solver shows the calculation time for the second velocity moment on the diagonal of the tensor, which is the most time-consuming part for deriving v rms pre $ {\boldsymbol{v}}_{\mathbf{rms}}^{\mathbf{pre}} $. We adopted the same number of Gaussians for the testing, i.e., 42 Gaussians for the lens light and 95 Gaussians for the composite mass model. JAX is primarily designed to maximize the parallelization performance on GPUs. We present the running time of the JAX code on a CPU to isolate the impact of the GPU acceleration. In practice, the code is intended to run on GPUs.

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