NEK5000 utilities for MATLAB

Jacopo Canton and Nicolò Fabbiane (in alphabetical order)
January, 2016

Functions

readnek.m

This function reads binary data from the nek5000 file format

[data,lr1,elmap,time,istep,fields,emode,wdsz,etag,header,status] = readnek(fname)

input

• fname: name of the file

output

• data: nek5000 data ordered as {iel,inode,[x|y|(z)|u|v|(w)|p|T|s_i]}
• lr1: element-size vector [lx1,ly1,lz1]
• elmap: reading/writing map of the elements in the file
• time: simulation time
• istep: simulation step
• fields: fields saved in the file
• emode: endian mode 'le' = little-endian, 'be' = big-endian
• wdsz: single (4) or double (8) precision
• etag: tag for endian indentification
• header: header of the file (string)
• status: status (< 0 something went wrong)

writenek.m

This function writes binary data in the nek5000 new file format

status = writenek(fname,data,lr1,elmap,time,istep,fields,emode,wdsz,etag)

input

• fname: name of the file
• data: nek5000 data ordered as {iel,inode,[x|y|(z)|u|v|(w)|p|T|s_i]}
• lr1: element-size vector [lx1,ly1,lz1]
• elmap: reading/writing map of the elements in the file
• time: simulation time
• istep: simulation step
• fields: fields saved in the file
• emode: endian mode 'le' = little-endian, 'be' = big-endian
• wdsz: single (4) or double (8) precision
• etag: tag for endian indentification

output

• status: status (< 0 something went wrong)

reshapenek.m

Reshape data from nekread to a meshgrid

[mesh1,mesh2,...] = reshapenek(data,nelx,nely)

input

• data: nek5000 data ordered as {iel,inode,[x|y|(z)|u|v|(w)|p|T|s_i]}
• nelx: number of element in the first direction (second index)
• nely: number of element in the second direction (first index)

output

• meshn: meshgrid of the n-th field in data

demeshnek.m

Demesh a meshgrid to data

[data] = reshapenek(mesh,lr1)

input

• mesh: meshgrid (fields along third index)
• lr1: element-size vector [lx1,ly1,lz1]

output

• data: nek5000 data ordered as {iel,inode,[x|y|(z)|u|v|(w)|p|T|s_i]}

This package has been also tested with Octave.