Free equations software for linux

Simple Equation makes it simple to put equations on the Web. Simple Equation project does not bother the user with the layout of the equation; it just displays it. The focus is on being simple to use.

One of the biggest obstacles to using mathematical expressions on the web is that the user currently needs to worry about layout. Web users should not have to learn a layout engine.

The class is built as a recursive parser. It is pretty easy to add operations to the parser, but it will not scale to a huge set of operations. That is OK, we want to keep things simple. At some point a layout engine may be required for a complexity level. This is not a layout engine.

Currently, only graphical output is generated, but it is hoped that MathML output can be generated automatically if the browser supports it instead of the graphic.

Easy Funktion is 2D function plotter software with an equation solver. Easy Funktion has an office-like GUI frontend and features a built-in pocket calculator, calculating with complex numbers (with special extensions for electronics, e.g. capacitor/inductor impedance), a function to export to spreadsheet software, and an advanced formula editor with automatic formatting.
This program alternatively supports an english version of the GUI, but at this time there is no separate english language download available.
In order to activate the english language GUI, do the following:
Open the folder where the program data is installed (/usr/share/easyfunktion). Rename the subfolder de to de_. You may need the root account to do this.
Enhancements:
- Unicode support for Unix.
- An English language GUI with English online help is now available for non-German installations.

GREYCstoration is an image regularization algorithm which processes an image by locally removing small variations of pixel intensities while preserving significant global image features, such as sharp edges and corners.
The most direct application of image regularization is denoising. By extension, GREYCstoration can also be used to inpaint or resize images.
GREYCstoration is based on state-of-the-art methods using nonlinear multi-valued diffusion PDEs (Partial Differential Equations) for image regularization. This kind of method generally outperforms basic image filtering techniques (such as convolution, median filtering, etc.), classically encountered in painting programs.
Other image denoising plugins are available (for instance, Noise Ninja, Neat Image ) but are not free, and the corresponding algorithms are kept secret.
Enhancements:
- This release consumes far less memory than the previous version (2.4.2), so it can deal with very large images.
- There are now processing modes for 16-bit/components and 32-bit float-valued images, as well as multi-thread support.
- A brand new plug-in for the GIMP is provided.

Qalculate! is a multi-purpose desktop calculator for GNU/Linux. Qalculate! project is small and simple to use but with much power and versatility underneath.
Features include customizable functions, units, arbitrary precision, plotting, and a user-friendly interface (KDE or GTK+).
Main features:
- Redesigned GUI with history view in the main window
- Display of as-you-type expression parsing and function hints
- Enhanced completion
- Scaling of result display to vertically fit the window
- Nicer history listing
- Enhanced result display with much nicer parentheses
- Meta modes
- 67 new units: bel (B) and neper (Np), information units such as bit and byte, many convenience units (km/h, deciliter, etc), and more.
- Binary prefixes
- Some new variables and functions
- Fixed help display in new yelp
- Fixed compile with cln-1.1.10
- Fixed regressions in simplification
- Fixed f(x) return type analysis (ex. log(x) represents a real number if x represents a positive). This was by accident unused.
- ...and many more bug fixes and enhancements...
Enhancements:
- Use Lambert W to solve more equations and avoid infinite loop when solving some equations
- More data on elements
- Fix simplification of (1-1/x)^3 and similar
- Fix clumsy mistakes in with prefixes leading to crashes
- Fix parsing of unit expressions (when converting) such as W/(m K)
- Add more exact values for sin() and cos() and avoid floating point underflow by, in approximate mode, checking against the value of pi
- Always input decimal separator sign on keypad separator press
- New units: typographic units, pouce, pied du roi, grams of TNT and tons of TNT
- New functions: lambertW(), addDays(), addMonths(), addYear(), addTime(), isNumber(), isReal(), isRational(), isInteger(), representsNumber(), representsReal(), representsRational(), representsInteger()
- New variable: omega constant
- Other minor fixes and enhancements

PETSc is a suite of data structures and routines for the scalable (parallel) solution of scientific applications modeled by partial differential equations.
PETSc library employs the MPI standard for all message-passing communication.
PETSc is easy to use for beginners. Moreover, its careful design allows advanced users to have detailed control over the solution process. PETSc includes a large suite of parallel linear and nonlinear equation solvers that are easily used in application codes written in C, C++, Fortran and now Python.
PETSc provides many of the mechanisms needed within parallel application codes, such as simple parallel matrix and vector assembly routines that allow the overlap of communication and computation. In addition, PETSc includes support for parallel distributed arrays useful for finite difference methods.
Main features:
- Parallel vectors
- scatters (handles communicating ghost point information)
- gathers
- Parallel matrices
- several sparse storage formats
- easy, efficient assembly.
- Scalable parallel preconditioners
- Krylov subspace methods
- Parallel Newton-based nonlinear solvers
- Parallel timestepping (ODE) solvers
- Complete documentation
- Automatic profiling of floating point and memory usage
- Consistent interface
- Intensive error checking
- Portable to UNIX and Windows
- Over one hundred examples
- PETSc is supported and will be actively enhanced for many years.
Enhancements:
- This release adds support for 2D and 3D mesh generation, refinement, partitioning, and distribution.
- It adds support for partitioning based upon arbitrary dimensional entities, e.g. vertices, faces, etc.
- It adds support for FIAT element generation.
- It adds support for higher order elements.
- A Poisson problem example in a separate repository has been added.
- The Hypre interface has been updated to use version 2.0.0.
- The Mumps interface has been updated to use version 4.7.3.
- The fftw interface has been updated to use v3.2alpha2.
- There are numerous bugfixes.

Eigen project is a lightweight C++ template library for vector and matrix math, a.k.a. linear algebra.
Unlike most other linear algebra libraries, Eigen focuses on the simple mathematical needs of applications: games and other OpenGL apps, spreadsheets and other office apps, etc. Eigen is dedicated to providing optimal speed with GCC.
- Its fixed-size classes are specially optimized for small sizes up to 4, although it is theoretically possible to specialize them to any size. They never cause dynamic memory applications and the simple operations on them are as fast as is possible at least for sizes up to 4 (see below).
- Its dynamic-size classes are more flexible and suitable for larger sizes.
Main features:
- No dependency. Only relies on the C++ Standard Library, and only does so for a few things.
- As a consequence: very good portability.
- Very good performance (tested with GCC, should apply to other compilers as well):
- The fixed-size classes are optimal in the sense that theyre just plain C arrays with methods manipulating them. They never cause dynamic memory allocations. Checked with valgrind.
- The assembly code generated by GCC has been carefully checked to make sure that loop unrolling and function inlining work as expected with "g++ -O2" and "g++ -O3".
- For the loops that GCC fails to unroll (mostly nested loops), we provide hand-unrolled versions for sizes up to 4.
- There is no "virtual" keyword in Eigen.
- Eigen never trades performance for syntactic sugar. When some method introduces a significant language overhead (e.g. returns an object by value), we provide an alternative method doing the same thing faster but without the syntactic sugar.
- Provides easy-to-use classes for solving systems of linear equations.
- Provides easy-to-use functions for linear regression analysis.
- Can perform LU decompositions and use them to invert matrices, compute rank, kernel, etc.
- Integrates nicely with OpenGL:
- Provides functions and classes for projective geometry.
- Stores matrices in column-dominant order, hence matrices can be directly passed between OpenGL and Eigen.
- Uses an OpenGL-like typedef naming scheme, for instance Vector3f for vectors of floats of size 3.
- Robust:
- Only uses algorithms that are guaranteed to work in all cases. For example, the LU decomposition is done with complete pivoting, which means that it works for all square matrices, even singular ones.
- Covered by extensive unit-tests.
- Thread-safe, though thats only as a consequence of staying simple and not trying to do advanced stuff like buffer sharing.
- Floating-point-correct. Eigen has a clear, simple and sound policy with respect to the inherent problems of IEEE754 floating-point arithmetic.
- Fully supports std::complex for matrices and vectors over the complex numbers.
- Is a pure template library and consists only of header files. Thus, using Eigen will only add a build-time dependency to your project.
- Uses standard asserts, controlled as usual by NDEBUG. To achieve optimal performance, turn them off by defining NDEBUG, e.g.
Enhancements:
- This release supports fixed-size classes that are optimized for small sizes of up to four dimensions for 3D geometry and OpenGL.
- Dynamic classes are more flexible and suitable for larger data.

TuxMathScrabble is a math-version of the popular board game for children aged 4-10. The game features drag-and-drop tiles for the user, while Tux moves his own.

The game challenges young people to construct compound equations and consider multiple abstract possibilities.

Dancing penguins come out of the tiles when your move is correct (like a cuckoo-clock). Tux is animated as well.