![]() Rlplot – was unable to properly read input file. Need more control over plotting parameters. ![]() PlotDrop – on the right track, but needs more features. Grace – still trying to work through input file browser. Gnumeric – nice spreadsheet capabilities. This post will be updated as further evaluations are made.ĭataScene – commercial package. Here are the results so far in alphabetical order. It should be useful for both quick visualization and publication quality plots. The program should be user-friendly and preferably free. The program should have options for grid, labels, scaling, changing plot limits, log format, multiple curves, legend, makers, etc. The data will then be plotted in a 2D line graph. In the mean time, I am looking for an alternate plotting program that will import ASCII text data which may be comma, space, or tab delimited. Identifying interactive, dynamic plotting methods in Python is still on my “to do” list. So far my Python knowledge only extends to making static plots. The Matlab export plot quality is ok but not great. I already have plotting capability via Matlab and Python/matplotlib running under Ubuntu. I am evaluating plotting programs for Ubuntu. Gfortran matrix_mult_cf.cpp fort_matmul_main.f -o mmult_cf -lstdc++ -lblas This approach requires some extra steps, but it avoids the complexity of passing 2D arrays, especially if any of the matrices is non-square. The fort_matmul_main subroutine uses dgemm to perform the actual multiplication.Īn important feature of this program set is that the C++ and Fortran codes pass the matrices back and forth using 1D arrays. The matrix_mult_cf program then calls a subroutine from fort_matmul_main to do the matrix multiplication. Furthermore, the number of A columns must be equal to the number of B rows. The input matrices may each have an arbitrary number of rows and columns up to a certain cell limit. The C++ program matrix_mult_cf reads in two matrices, A & B. The set consists of two programs: (right mouse click. It is complied and run in an Ubuntu system. This is another matrix multiplication project using the BLAS function dgemm. Notes to self so I can remember the processing steps:Įxtract audio: avconv -i input.3gp output.wavĪvconv -i input.avi -vcodec copy -acodec copy -ss 00:00:09 -t 00:00:21 output.avi Here is the time history: Q400.txt – time(sec) & unscaled sound pressure This frequency and its integer harmonics are clearly visible in the spectral analysis of the audio track. There are six blades on each engine, so the blade passing frequency is 85 Hz. The PW150A engine/propeller rotation rate during takeoff and climb is 1020 RPM, but is throttled back at cruise altitude to 850 RPM, or 14.17 Hz. I captured the following video during cruise using a Motorola/Android phone (when it was safe for passengers to turn on their portable electronic devices): Audio/Video File This model aircraft has two Pratt & Whitney Canada PW150A turboprop engines. I recently flew from Spokane to Seattle, Washington on an Alaska/Horizon Air Bombardier Q400 aircraft, similar to the one in the above image. Here is an example for calling gnuplot from within a Fortran program running in Ubuntu: fortran_gnuplot_demo.fĬALL SYSTEM(‘gnuplot gnuplot_t -persist’) ![]() Here is an example for plotting a shock response spectrum with two curves and a legend. Here is an example for plotting a power spectral density in log-log format, with some manually added tics. The png file can be accessed by other applications but may require the following command first depending on the application, operating system, etc. The above plot was made using Gnuplot Version 4.6 patchlevel 3. The drop_t file also generates a corresponding png file as shown at the beginning of this post. The follow command is then entered into the gnuplot window: Here is an alternate example that plots the two curves in separate windows: plot_drop_2.plt Time histories: drop.txt & drop_velox.txt Here is an example for generating a graph with two subplots using the multiplot command. Here is an example for plotting the time history shown above using the following files: Gnuplot can be downloaded from previous link or from: softpedia gnuplot ![]() It was originally created to allow scientists and students to visualize mathematical functions and data interactively, but has grown to support many non-interactive uses such as web scripting The source code is copyrighted but freely distributed (i.e., you don’t have to pay for it). Gnuplot is a portable command-line driven graphing utility for Linux, OS/2, MS Windows, OSX, VMS, and many other platforms.
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