  The detection of gravitational waves from compact binary coalescence (CBC)
has allowed us to probe the strong-field dynamics of General Relativity (GR).
Among various tests performed by the LIGO-Virgo-KAGRA collaboration are
parameterized tests, where parameterized modifications to GR waveforms are
introduced and constrained. This analysis typically requires the generation of
more than millions of computationally expensive waveforms. The computational
cost is higher for a longer signal, and current analyses take weeks-years to
complete for a binary neutron star (BNS) signal. In this work, we present a
technique to accelerate the parameterized tests using a multiband decomposition
of likelihood, which was originally proposed to accelerate parameter estimation
analyses of CBC signals assuming GR by one of the authors. We show that our
technique speeds up the parameterized tests of a 1.4 Msun-1.4 Msun BNS signal
by a factor of O(10) for a low-frequency cutoff of 20 Hz. We also verify the
accuracy of our method using simulated signals and real data.
