Shulou(Shulou.com)05/31 Report--

In this article, the editor introduces in detail "what are the five big data visualization tools of Linux" with detailed contents, clear steps and proper handling of the details. I hope that this article "what are the five big data visualization tools of Linux" can help you solve your doubts.

Gnuplot

Gnuplot is a very good visualization tool that has been around since 1986. Without a picture of gnuplot, it would be difficult to read the paper. Although gnuplot is command-line driven, it is also evolving and can now support many non-interactive applications, such as it can be used as a drawing engine for GNU Octave.

Gnuplot is portable and can run on UNIX ®, Microsoft ®Windows ®, Mac OS ®X, and many other platforms. It can support a wide range of output formats from postscript to the recent PNG.

Gnuplot can operate in batch mode and provides a command script to generate a graph, which is also run in non-interactive mode, which allows us to try its features to see how their drawings work.

There is a standard math library corresponding to UNIX's math library available in gnuplot. The arguments to the function support integers, real types, and complex types. You can configure the math library to radians or angles (the default is radians).

In order to draw, gnuplot can use the plot command to generate 2murd graphics, or the splot command to generate 3merd graphics (as 2Murd projection). Using the plot command, gnuplot can operate in a Cartesian 2D coordinate system. The splot command defaults to the Cartesian coordinate system, but it can also support spherical or cylindrical coordinate systems. You can also draw contours in the drawing (as shown in figure 1 below). There is a new style of drawing pm3d that can support the use of 3murd and 4D data mapped using color palettes as maps or surface maps.

The following is a simple example of gnuplot, which shows a 3murd graph with contours and hidden lines eliminated. Listing 1 shows the gnuplot command used, and figure 1 shows the generated graphical results.

Listing 1. Simple gnuplot function diagram

Listing 1 fully shows how simple the gnuplot command set is. The sampling speed and drawing density are determined by samples and isosamples, and the title is provided for the graph by the title parameter. At the same time, basic contours and hidden line elimination features are also enabled, and the final drawing is created using splot commands using functions within the mathematical library. The result is shown in figure 1.

Figure 1. A simple drawing of gnuplot

In addition to creating function diagrams, gnuplot can also do a good job of drawing graphics contained in files. Consider the xUnip y data pair shown in listing 2 (a short version of this file). The data pairs given in this file represent data on the x and y axes in a two-dimensional space.

Listing 2. Sample data file (data.dat) for gnuplot

If you want to draw this data in a two-dimensional space and connect each data point with a line, you can use the gnuplot script shown in listing 3.

Listing 3. The Gnuplot script used to draw the data in listing 2

The result is shown in figure 2. Note that gnuplot automatically gives the scale of the axis, but if you need to mark the position of the graph, you can control it.

Figure 2. Use data files for simple drawing in gnuplot

Gnuplot is a good visualization tool. It is very famous and is part of many GNU/Linux distributions. However, if you want to do basic data visualization and numerical calculations, then GNU Octave may be the tool we are looking for.

GNU Octave

GNU Octave is a high-level language, mainly designed for numerical calculation. It is a strong competitor to Matlab commercial software produced by MathWorks. In addition to the simple command set provided by gnuplot, Octave provides a rich language for mathematical programming. We can even write our own applications in C or C++ and interact with Octave.

Octave was originally written in 1992 as an auxiliary software in the textbook of chemical reactor design. The author hopes to help students solve reactor design problems without debugging Fortran programs. As a result, a very useful language is obtained and provides an interactive environment for solving numerical problems.

Octave can operate non-interactively in a scripted mode, or through C and C++ language bindings. Octave itself has a very rich language that looks very similar to C and has a large math library, including special functions used in signal and image processing, audio processing, and control theory.

Because Octave uses gnuplot as its back-end implementation, everything you can draw with gnuplot can be drawn using Octave. Octave does have a richer language for computing. It has many obvious advantages, but it still has some limitations of gnuplot.

In the example provided on the Octave-Forge Web site below (SimpleExamples), a Lorentz Strange Attractor is drawn. Listing 4 shows the interactive dialog used by Octave on a Windows platform that uses Cygwin. This example shows the use of lsode, a common differential equation solver.

Listing 4. Using Octave to render Lorentz Strange Attractor

Figure 3 shows the output of the Octave code in listing 4.

Figure 3. Lorentz diagrams drawn with Octave

GNU Octave (consistent with gnuplot) can use the multiplot feature to render multiple graphics on a single page. Using this feature, you can define how many drawings to create, and then use the subwindow command to customize specific drawings. After defining the child window, you can generate your own graph normally, and then jump to the next child window (see listing 5).

Listing 5. Generate multiple drawings in Octave

The generated multi-graph page is shown in figure 4. This is a good feature to collect related graphics together for comparison and comparison.

Figure 4. Using GNU Octave to draw multiple graphs

We can think of Octave as a high-level language that uses gnuplot as a background implementation for visualization. It provides a rich math library and is a good free replacement for Matlab. It can be easily extended using user-developed packages for voice processing, optimization, symbolic computing, etc. Octave is available in some GNU/Linux distributions, such as Debian, and can also be used on Windows and Mac OS X that use Cygwin.

Scilab

Scilab is very similar to GNU Octave in enabling numerical computation and visualization. Scilab is an interpreter and high-level language used by engineering and scientific applications all over the world.

Scilab was born in 1994 and was designed by INRIA (Institut national de recherche en informatique et en automatique) and ENPC (É cole Nationale des Ponts et Chauss é es) in France. Scilab has been maintained by Scilab Consortium since 2003.

Scilab includes a large library of mathematical functions that can be extended with programs written in high-level languages such as C and Fortran. It also has the ability to overload data types and operations. It includes an integrated high-level language, but this language is slightly different from the C language.

There are many toolkits in Scilab that provide graphical animation, optimization, statistics, icons and networks, signal processing, hybrid dynamic system simulation and simulation, and many other community-contributed functions for 2murd and 3murd.

Scilab is available on most UNIX systems, as well as on newer Windows operating systems. Like GNU Octave, Scilab is well documented. Because it is an European project, you can also find many documents and articles written in languages other than English.

After launching Scilab, a window is displayed so that we can interact with it (see figure 5).

Figure 5. Interact with Scilab

In this example, you first create a vector (t) whose values range from 0 to 2PI (step size is 0.2). A 3murd graph is then generated (using zemof (xmemy), or a surface at the xi,yi point). Figure 6 shows the generated graph.

Figure 6. The Scilab diagram generated by the command in figure 5

Scilab includes many libraries and functions that can draw graphics with minimal complexity. Here is an example of generating a simple 3D bar chart:

-- > hist3d (5* (rand (5Jing 5))

First, rand (5, 5) builds a matrix of 5, 5, and contains some random values (with a * * value of 5). This matrix is passed to the function hist3d. The resulting bar chart is shown in figure 7.

Figure 7. Generate a random 3D bar chart

Scilab is very similar to Octave. They all have a large basis for community participation. Scilab is written in Fortran 77 and Octave in C++. Octave uses gnuplot for visualization; Scilab provides its own library. If you are very familiar with Matlab, then Octave is a good choice because it strives to achieve compatibility with Matlab. Scilab includes many mathematical functions, so it is very suitable for signal processing. If you're still not sure which tool to use, you can try it all. They are good tools and can be used to accomplish different tasks.

MayaVi

MayaVi, which means magician in Sanskrit, is a data visualization tool that binds Python with a powerful visualization kit (VTK) for graphical display. MayaVi also provides a graphical user interface (GUI) developed using the Tkinter module. Tkinter is a Tk interface that is usually used with Tcl.

MayaVi was originally developed for Computational Fluid Dynamics (CFD) as a visualization tool. When people realized its utility in other fields, it was redesigned as a general scientific data visualization tool.

The magic behind MayaVi comes from VTK. VTK is an open source system for data visualization and image processing, and it is widely used in the scientific community. VTK encapsulates a lot of functionality through scripted interfaces for Tcl/Tk, the Java programming language, and Python plus the C++ library. VTK is portable on many operating systems, including UNIX, Windows, and MAC OS X.

The MayaVi shell around VTK can be imported from other Python programs as a Python module and scripted through the Python interpreter. The tkinter GUI provided by MayaVi allows you to configure and apply filters, as well as render some lighting effects on a visual basis.

Figure 8 is an example of visualization using MayaVi on the Windows platform.

Figure 8. 3murd visualization using MayaVi/VTK display (cardiac CT scan)

MayaVi is an interesting example of extending VTK in the Python scripting language.

Maxima

Maxima is a symbolic and numerical program that is the blood of Octave and Scilab. The original development team of Maxima started at MIT in the 1870s and is still being maintained. The original version (a computer algebra system), called DOE Macsyma, opened the way for better-known applications such as Mathematica that were later developed.

Maxima provides a set of desired feature sets (such as calculus, analytic linear systems, and nonlinear equality sets) as well as symbolic computing capabilities. You can also find some clues to Lisp in Maxima (from functions such as references, map, and apply). Maxima is written in Lisp and can execute Lisp code in a Maxima session.

Maxima has a good online help system, which is based on hypertext. For example, if you want to know how a particular Maxima function works, you can simply type example (desolve), which provides a lot of sample usage.

Maxima also has some interesting features, such as rules and patterns. These rules and patterns are used by programs that simplify expressions. Rules can be used for commutative and non-commutative algebras.

Maxima is very similar to Octave and Scilab: both interpreters can be used to interact with users, and the results are provided directly in the same window, or can be displayed in another window. In figure 9, a simple 3murd graph is requested.

Figure 9. Interact with Maxima

The resulting graph is shown in figure 10.

Figure 10. The Maxima graph generated by the command in figure 9

After reading this, the article "what are the five big data Visualization tools of Linux" has been introduced. If you want to master the knowledge of this article, you still need to practice and use it to understand it. If you want to know more about related articles, you are welcome to follow the industry information channel.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.