View source for $$\eta$$ scaling for dynamical nhyp

We performed a scaling test of the $$\eta$$ parameter on a single $$24^3 \times48$$ nhyp dynamical lattice. We want to determine a regime of $\eta$ values where the $$\eta^2$$ scaling of the mass shift is valid. As we go to smaller values of $\eta$ numerical limitations will begin to arise. We want to find where this break down occurs. We did the analysis for 2 different precisions for the CG inverter: $$10^{-8}$$ and $$10^{-13}$$.


For the $$10^{-8}$$ precision we ran the simulation for 10 values of $$\eta$$ starting from $$\eta_0 = 3.0\times 10^{-5}$$. The subsequent values of $$\eta$$ are in powers of 2, i.e. $$\eta_1 = 2^1 \eta_0$$,  $$\eta_2 = 2^2 \eta_0$$ etc. For the $$10^{-13}$$ precision we ran the simulation for 16 values of $$\eta$$ starting from $$\eta_0 = 4.6875\times 10^{-7}$$. This value is chosen such that $$2^7( 4.6875\times 10^{-7}) = 3.0\times 10^{-5}$$.


We plot $$(G_E(t) -G_0(t))/\eta^2$$ as a function of $$\eta$$. We expect a constant behavior in the region where the $$\eta^2$$ scaling is valid.  The plots below show our results for the neutron at several different time slices. The parameters used in this analysis are listed in the table below. 

==='''Configuration'''=== 
knhyp242448_beta7.1_kappa0.1282_023

ran on Fermilab.

{| class="wikitable" style="text-align: center;" 

! CG precision !! 1e-8 !! 1e-13 
|-
! $$\kappa$$
| 0.1282 || 0.1282
|-
! n iterations ~
| 700 ||1250
|-
! timing for 1 inversion ~
| 15 sec || 22 sec
|-
! N GPUs
| 2 || 4
|}

==='''Plots'''===
[[File:Etas_1e-8.png|left|430px]]
[[File:Etas_4.6875e-7.png|right|430px]]