Astrophysics Source Code Library

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Searching for codes credited to 'Fang, Xiao'

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[ascl:1603.006] FAST-PT: Convolution integrals in cosmological perturbation theory calculator

FAST-PT calculates 1-loop corrections to the matter power spectrum in cosmology. The code utilizes Fourier methods combined with analytic expressions to reduce the computation time down to scale as N log N, where N is the number of grid point in the input linear power spectrum. FAST-PT is extremely fast, enabling mode-coupling integral computations fast enough to embed in Monte Carlo Markov Chain parameter estimation.

[ascl:1911.022] FFTLog-and-beyond: Generalized FFTLog algorithm

FFTLog-and-beyond takes the FFTLog algorithm for single-Bessel integrals and generalizes it for integrals containing a derivative of the Bessel function to solve the non-Limber integrals. The full non-Limber angular power spectrum integral is simplified by noting the small contribution from unequal-time nonlinear terms; this significantly reduces the computation and avoids the double-Bessel integral. The original FFTLog algorithm is also extended to compute integrals containing derivatives of Bessel functions, which can be used to efficiently compute angular power spectra including redshift-space distortions (RSD) and Doppler effects. C and Python versions of the code are available.

[ascl:2006.004] 2D-FFTLog: Generalized FFTLog algorithm for non-Gaussian covariance matrices

2D-FFTLog takes the FFTLog algorithm for 1D Hankel transforms and generalizes it for 2D Hankel transforms. The algorithm is useful for efficiently computing non-Gaussian covariance matrices of cosmological 2-point statistics in configuration space from Fourier space covariances. Fast bin-averaging method is also developed for both the logarithmic binning and general binning choices. C and Python versions of the code are available.

[ascl:2006.005] CosmoCov: Configuration space covariances for projected galaxy 2-point statistics

CosmoCov computes configuration space covariances for projected galaxy 2-point statistics based on the CosmoLike (ascl:2006.006) framework. The package provides a flat sky covariance module, computed with the 2D-FFTLog (ascl:2006.004) algorithm, and a curved sky covariance module.