[Nek5000-users] Reading binary data

[nek5000-users at lists.mcs.anl.gov]

Hi Fred,

header: 132 bytes
endian test tag: 4 bytes
element mapping: nel* 4 bytes
data: nfields*nxyz*nel* wdsizo (where wdsizo is 4 or 8 bytes)
metadata (min/max values): nfields*2*nel * 4 bytes

Stefan


On May 6, 2010, at 10:14 AM, nek5000-users at lists.mcs.anl.gov wrote:

> Dear Neks,
> 
> I have written a small Matlab function to read in the binary result files. Mostly I understood the structure including the header and the structure of the data. After reading in the data (in my case I only wrote x,y,z,u,v,w,p) there was still some information in the result file. See
> % ???
> for i=1:252
> rest(i)=fread(fid,1,'float');
> end
> in the function. Can you explain me what is this?? I added the Matlab function.
> 
> Best , Fred
> function [x,y,z,u,v,w,p,nel1,nmax,time,step] = nek_readbin(file)
> % Function nek_readbin
> %
> % Open *0.f0** binary NEK5000 result file
> % Call: [x,y,z,u,v,w,p,ne,nmax,time,step]=nek_readbin('file')
> %
> % Author: Frederik Folke
> % Date: 06/05/2010
> 
> %------------------------------------------------------------------------%
> %clear all
> 
> % Read header of ouput-file
> [a,n,nx,ny,nz,nel1,nel2,time,step]=...
>    textread(file,'%5c %d %d %d %d %d %d %f %d' ,1);
> %source code from prepost.f
> %  write(hdr,1) wdsizo,nxo,nyo,nzo,nelo,nelgt,time,istep,fid0,nfileoo
> % $         ,   (rdcode1(i),i=1,10)        ! 74+20=94
> %1 format('#std',1x,i1,1x,i2,1x,i2,1x,i2,1x,i10,1x,i10,1x,e20.13,
> % $       1x,i9,1x,i6,1x,i6,1x,10a)
> clear a;
> 
> %------------------------------------------------------------------------%
> % Open result file and skip header
> fid=fopen(file)
> for i=1:52
>  bin(i)=fread(fid,1,'int');
> end
> 
> nmax=(nx*ny*nz);
> 
> % Initialize x,y,z,u,v,w,p
> x2=zeros(nmax*nel1,1);
> y2=zeros(nmax*nel1,1);
> z2=zeros(nmax*nel1,1);
> u2=zeros(nmax*nel1,1);
> v2=zeros(nmax*nel1,1);
> w2=zeros(nmax*nel1,1);
> p2=zeros(nmax*nel1,1);
> 
> % Read data (here: x,y,z,u,v,w,p)
> k=0;
> l=0;
> m=0;
> for i=1:nel1    %maybe nel2??
>    for j=1:nmax
>        k=k+1;
>        x2(k)=fread(fid,1,'float');
>    end
>    for j=1:nmax
>        l=l+1;
>        y2(l)=fread(fid,1,'float');
>    end   
>    for j=1:nmax
>        m=m+1;
>        z2(m)=fread(fid,1,'float');
>    end
> end
> 
> 
> k=0;
> l=0;
> m=0;
> n=0;
> for i=1:nel1   %maybe nel2??
>    for j=1:nmax
>        k=k+1;
>        u2(k)=fread(fid,1,'float');
>    end
>    for j=1:nmax
>        l=l+1;
>        v2(l)=fread(fid,1,'float');
>    end   
>    for j=1:nmax
>        m=m+1;
>        w2(m)=fread(fid,1,'float');
>    end 
> end
> 
> k=0;
> for i=1:nel1   %maybe nel2??
>   for j=1:nmax
>        k=k+1;
>        p2(k)=fread(fid,1,'float');
>    end 
> end
> 
> % ???
> for i=1:252
>  rest(i)=fread(fid,1,'float');
> end
> 
> fclose('all');
> 
> end_______________________________________________
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