--- name: "field" section: "1rheolef" platform: "linux" package: "rheolef" version: "7.2-4" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/field" --- # field(1rheolef) plot a field (rheolef-7.2) ## NAME field - plot a field (rheolef-7.2) ## SYNOPSIS ``` field [options] file[.field[.gz]] ``` ## DESCRIPTION Read and output a finite element field from file. ## EXAMPLE ``` field square.field field square.field -bw field box.field ``` ## INPUT FILE SPECIFICATION filename Specifies the name of the file containing the input field. `-` Read field on standard input instead on a file. `-name` When the field comes from standard input, the file base name is not known and is set to 'output' by default. This option allows one to change this default. Useful when dealing with output formats (graphic, format conversion) that creates auxiliary files, based on this name. `-I`*dir* \ `-I` *dir* Add *dir* to the Rheolef file search path. This option is useful e.g. when the mesh .geo and the .field fikes are in different directories. This mechanism initializes a search path given by the environment variable `RHEOPATH`. If the environment variable `RHEOPATH` is not set, the default value is the current directory. `-mark` *string* \ `-catch` *string* \ `-catchmark` *string* Jump across the file to the specified *string* . Label start at the beginning of a line, preceded by a `#` mark (see **catchmark(3)**). ## OUTPUT FILE FORMAT OPTIONS - `-field` `-text` Output field on standard output stream in Rheolef ascii (field or geo) text file format. - `-gmsh` Output field on standard output stream in `.gmsh` file format. - `-gmsh-pos` Output field on standard output stream in `.gmsh-pos` file format, suitable for mesh adaptation purpose. - `-bamg-bb` Output field on standard output stream in bamg-bb text file format, suitable for mesh adaptation purpose. - `-image-format` *string* For image or video capture. The supported argument are `.jpg`, `.png`, `.tif` and `.bmp`. This option should be combined with the `paraview` render. The output file is basename.png where *basename* is the name of the mesh, or can be set with the `-name` option. `-resolution` *int* *int* For the resolution of an image or a video capture. The argument is a couple of sizes, separated by a white space. This option can be used together with the `-image-format` for any of the bitmap image formats. This option requires the `paraview` render. ## GETTING INFORMATION `-min` \ `-max` Print the min (resp. max) value of the scalar field and then exit. `-get-geo` Print the name of the mesh associated to the field and exit. ## RENDER OPTIONS - `-gnuplot` Use the `gnuplot` tool. This is the default in one dimension. - `-paraview` Use the `paraview` tool. This is the default for two- and tri-dimensional geometries. ## RENDERING OPTIONS - `-color` `-gray` `-black-and-white` `-bw` Use (color/gray scale/black and white) rendering. Color rendering is the default. `-[no]showlabel` Show or hide title, color bar and various annotations. Default is to show labels. `-label *string*
‍ Set the label to show for the represented value. This supersedes the default value.
`-\[no\]elevation`
‍ For two dimensional field, represent values as elevation in the third dimension. The default is no elevation.
`-scale`*float*
‍ Applies a multiplicative factor to the field. This is useful e.g. in conjunction with the`elevation`option. The default value is 1.
`-\[no\]stereo`
‍ Rendering mode suitable for red-blue anaglyph 3D stereoscopic glasses. This option is only available with`paraview`.
`-\[no\]fill`
‍ Isoline intervals are filled with color. This is the default. When`-nofill`, draw isolines by using lines.
`-\[no\]volume`
‍ For 3D data, render values using a colored translucid volume. This option requires the`paraview`code.
`-\[no\]cut`
‍ Cut by a specified plane. The cutting plane is specified by its origin point and normal vector. This option requires the`paraview`code.
`-origin`*float* [*float* [*float*]]
‍ Set the origin of the cutting plane. Default is (0.5, 0.5, 0.5).
`-normal`*float* [*float* [*float*]]
‍ Set the normal of the cutting plane. Default is (1, 0, 0).
`-isovalue`[*float*] \n `-iso`[*float*]
‍ Draw 2d isoline or 3d isosurface. When the optional float is not provided, a median value is used. This option requires the`paraview`code.
`-noisovalue`
‍ Do not draw isosurface. This is the default.
`-n-iso`*int*
‍ For 2D visualizations, the isovalue table contains regularly spaced values from fmin to fmax, the bounds of the field.
@addindex vorticity @addindex stream function `-n-iso-negative`*int*
‍ The isovalue table is split into negatives and positives values. Assume there is n_iso=15 isolines: if 4 is requested by this option, then, there will be 4 negatives isolines, regularly spaced from fmin to 0 and 11=15-4 positive isolines, regularly spaced from 0 to fmax. This option is useful when plotting e.g. vorticity or stream functions, where the sign of the field is representative.
@addindex projection @addindex approximation P1 `-proj`*approx* `-proj`
‍ Convert all selected fields to approximation *approx* by using a L2 projection. When argument is omitted,`P1`approximation is assumed.
`-lumped-proj`
‍ Force`P1`approximation for L2 projection and use a lumped mass matrix for it.
`-round`[*float*]
‍ Round the input up to the specified precision. This option, combined with`-field`, leads to a round filter. Useful for non-regression test purpose, in order to compare numerical results between files with a limited precision, since the full double precision is machine-dependent.
`-subdivide`*int*
‍ When using a high order geometry, the number of points per edge used to draw a curved element. Default value is the mesh order.
`-deformation` `-velocity`
‍ Render vector-valued fields as deformed mesh using`paraview`or`gnuplot`. This is the default vector field representation. When`velocity`, render vector-valued fields as arrows using`paraview\` instead. ## COMPONENT EXTRACTION AND DOMAIN REDUCTION `-comp` *int* \ `-comp` *string* Extract the i-th component of a vector-valued field. For a tensor-valued field, indexing components as `00`, `01`, `11`... is supported. `-domain` *name* Reduce the visualization to the specified domain name. ## OTHERS OPTIONS `-[no]verbose` Print messages related to graphic files created and command system calls (this is the default). \`-\[no\]clean Clear temporary graphic files (this is the default). `-[no]execute` Execute graphic command (this is the default). The `-noexecute` variant is useful in conjunction with the `-verbose` and `-noclean` options in order to modify some render options by hand. ## FIELD FILE FORMAT It contains a header and a list values at degrees of freedom. The header contains the `field` keyword followed by a line containing a format version number (presently 1), the number of degrees of freedom (i.e. the number of values listed), the mesh file name without the `.geo` extension the approximation (e.g. P1, P2, etc), and finally the list of values: A sample field file write ``` field 1 4 square P1 0.0 1.0 2.0 3.0 ``` See also **geo(1)** for the `.geo` mesh file format. ## EXAMPLES The following command send to `vtk` the cuted 2d plane of the 3d field: ``` field cube.field -cut -normal 0 1 0 -origin 0.5 0.5 0.5 -vtk ``` Next, let us generate the cuted 2d field and its associated mesh: ``` field cube.field -cut -normal 0 1 0 -origin 0.5 0.5 0.5 -text > cube-cut.field ``` For drawing the isosurface: ``` field cube.field -isovalue 0.5 ``` Finally, let us generate the isosurface as a 3d surface mesh in the `.geo` file format: ``` field cube.field -isovalue 0.5 -text > isosurf.geo ``` This file is then suitable for others treatments. ## IMPLEMENTATION This documentation has been generated from file main/bin/field.cc ## AUTHOR Pierre Saramito \ ## COPYRIGHT Copyright (C) 2000-2018 Pierre Saramito \ GPLv3+: GNU GPL version 3 or later \. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.