Changes between Version 21 and Version 22 of FAQ


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Timestamp:
Dec 22, 2010, 10:00:32 PM (9 years ago)
Author:
dtodd
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  • FAQ

    v21 v22  
    3232
    3333=== Why does Simulation appear to hang or slow down for large spin systems? ===
    34 Simulation relies on the [gamma:wiki GAMMA] package. When doing calculations with a spin of 8,9, or 10, your system may appear to slow down or even hang. At a spin count of 7, a single FID experiment takes GAMMA 0.4 seconds, but at spin 10 it takes 1 hour and 24 minutes (on a 2.66 GHz Intel machine). [gamma:GammaVsSpin Here is a list of GAMMA timing results for various spin sizes]. The "slow down" may be compounded if doing a large number of individual simulations for different timings, or spacial locations. Note: The time it takes to run these specific jobs is virtually identical in GAMMA - when compared to Simulation - as there is little overhead converting arrays to and from Python, as compared to the overall time of the calculations.
     34When doing calculations with a spin of 8,9, or 10, your system may appear to slow down or even hang. A likely explanation is that for larger spins it take a much longer time for the spectral calculations in the underlying [gamma:wiki GAMMA] package. For example, at a spin count of 7, a single FID experiment takes GAMMA 0.4 seconds, but at spin 10 it takes 1 hour and 24 minutes (on a 2.66 GHz Intel machine). [gamma:GammaVsSpin Here is a list of GAMMA timing results for various spin sizes]. The "slow down" may be compounded if doing a large number of individual simulations for different timings, or spacial locations.
    3535
     36Note: The time it takes to run these specific jobs is virtually identical in GAMMA versus Simulation - as there is little overhead (e.g. converting arrays between python and C++) when compared to the overall time of the calculations.
     37