<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi,<div class="">the question is very simple, and I believe to already have the answer but still, is worth trying.</div><div class="">When managing large files in NCL I always have to create new tricks in the debugging phase in order to avoid long waiting times. Today I was trying to read a dataset with 401x401x150 points (approx 48 GB):</div><div class=""><br class=""></div><div class=""><div class=""><font face="Menlo" style="font-size: 11px;" class=""> data = addfile("./complete_remap.nc", "r")</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> </font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> p = data->pres ; pressure [Pa]</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> t = data->temp ; temperature [K]</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> qv = data->qv ; qv [ kg/kg]</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> z = data->z_mc ; geopotential [m]</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> </font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> print("FILEs READ in "+get_cpu_time()+"s")</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""><br class=""></font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> rh=relhum(t, qv, p)</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> td=dewtemp_trh(t, rh)</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> </font></div><div class=""><font face="Menlo" style="font-size: 11px;" class=""> print("COMPUTATION "+get_cpu_time()+"s”)</font></div><div class=""><br class=""></div><div class="">and getting the following printout.</div><div class=""><br class=""></div><div class=""><div class=""><font face="Menlo" style="font-size: 11px;" class="">(0)<span class="Apple-tab-span" style="white-space:pre"> </span>FILEs READ in 47.4748s</font></div><div class=""><font face="Menlo" style="font-size: 11px;" class="">(0)<span class="Apple-tab-span" style="white-space:pre"> </span>COMPUTATION 499.424s</font></div></div><div class=""><br class=""></div><div class="">Is there any way to speed up the process? I tried to use as few definition as possible and only pre-included functions. </div><div class="">Why is the computation part taking so long? Maybe it’s something that depends on the system RAM? </div><div class="">In the meantime the best workaround that I could think of consisted in subsetting a region in the previous data and testing the code only on that file.</div><div class=""><br class=""></div><div class="">Cheers</div><div class="">
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