---
name: "viper"
section: "1"
platform: "linux"
package: "python-viper"
version: "1.0.0-1"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/viper"
---

# viper(1)

the simple FEniCS run-time plotter

## NAME

Viper - the simple FEniCS run-time plotter

## SYNOPSIS

**viper** \[*OPTIONS*\]

## DESCRIPTION

Viper is a minimalistic scientific plotter and run-time visualization module. Some its the features includes:\

\* Light-weight and minimalistic\
 \* Extended keybindings\
 \* Interactive\
 \* Save as png, VTK\
 \* 2D and 3D\
 \* Scalar, vector, and displacement fields\
 \* Multiple input formats\
 \* In PyCC mode; direct plotting of NumPy arrays over DOLFIN meshes\
 \* Can be used as standalone plotting application, or used as part of\
   PyDOLFIN \

## OPTIONS

- **-h**, **--help**

  Display help text and exit.

- **-i** file, **--input** file

  Specify input file.

- **-o** file, **--output** file

  Specify output file.

- **-l** lut file, **--lut** lut file

  Specify lookup table (LUT) file.

- **-d** data file, **--data** data file

  Specify data file.

## EXAMPLE

Viper has support for visualizing meshes and solutions in DOLFIN:\

	from dolfin import \*\

	\# Plot a mesh\
\
 	mesh = UnitCube(16, 16, 16)\
\
 	plot(mesh)\

	\# Plot a scalar function\
\
 	u = Function("poisson.xml")\
\
 	plot(u)\

	\# Plot a vector function as a displacement field\
\
 	d = Function("elasticity.xml")\
\
 	plot(d, mode="displacement")\

	\# Save as png\
\
 	p = plot(mesh)\
\
 	p.write\_png("mesh.png")\

	\# Save as VTK\
\
 	p = plot(u)\
\
 	p.write\_vtk("poisson.vtk")\

## BUGS

- Send comments, questions, bug reports etc. to fenics-viper@lists.launchpad.net.

  ## LICENSE

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program.  If not, see \<http://www.gnu.org/licenses/\>.

## AUTHOR

Ola Skavhaug \<skavhaug@simula.no\>

This manual page was written by Johannes Ring \<johannr@simula.no\>.