http://code.activestate.com/recipes/tags/mathematics-fractal/2016-07-31T22:50:28-07:00ActiveState Code Recipes2016-07-23T07:58:14-07:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/580691-hamming-error-correction-code/

<p style="color: grey"> Python recipe 580691 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/encoding/">encoding</a>, <a href="/recipes/tags/engineering/">engineering</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/utility/">utility</a>). </p> <p>Hamming(7,4) Error Correction Code (ECC).</p>

2015-11-07T18:44:05-08:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/579122-simple-infix-expression-evaluation/

<p style="color: grey"> Python recipe 579122 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/algorithm/">algorithm</a>, <a href="/recipes/tags/algorithms/">algorithms</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/stack/">stack</a>). </p> <p>Simple infix expression evaluation using a stack.</p>

2016-07-31T22:50:28-07:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/580695-image-projection-onto-sphere/

<p style="color: grey"> Python recipe 580695 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/graphics/">graphics</a>, <a href="/recipes/tags/image/">image</a>, <a href="/recipes/tags/images/">images</a>, <a href="/recipes/tags/image_processing/">image_processing</a>, <a href="/recipes/tags/imaging/">imaging</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/pil/">pil</a>). </p> <p>Image projection onto sphere using Equirectangular map projection.</p> <p>Download the test image from the Wikipedia page!</p>

2015-11-08T05:08:26-08:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/579123-infix-expression-evaluation/

<p style="color: grey"> Python recipe 579123 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/algorithm/">algorithm</a>, <a href="/recipes/tags/algorithms/">algorithms</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/stack/">stack</a>). </p> <p>Infix expression evaluation using two stacks.</p>

2015-01-03T03:39:34-08:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578997-2d-discrete-fourier-transform/

<p style="color: grey"> Python recipe 578997 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/image/">image</a>, <a href="/recipes/tags/images/">images</a>, <a href="/recipes/tags/image_processing/">image_processing</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/signal_processing/">signal_processing</a>). </p> <p>2D Discrete Fourier Transform (DFT) and its inverse.</p> <p>Calculates 2D DFT of an image and recreates the image using inverse 2D DFT.</p> <p>Computation is slow so only suitable for thumbnail size images.</p>

2014-12-27T21:43:53-08:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578994-discrete-fourier-transform/

<p style="color: grey"> Python recipe 578994 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/signal/">signal</a>, <a href="/recipes/tags/signal_processing/">signal_processing</a>). </p> <p>Discrete Fourier Transform and Inverse Discrete Fourier Transform</p> <p>To test, it creates an input signal using a Sine wave that has known frequency, amplitude, phase. Later it calculates DFT of the input signal and finds its frequency, amplitude, phase to compare.</p>

2014-09-10T02:21:27-07:00Ethan Hannhttp://code.activestate.com/recipes/users/4190746/http://code.activestate.com/recipes/578931-perfect-square-checker/

<p style="color: grey"> Python recipe 578931 by <a href="/recipes/users/4190746/">Ethan Hann</a> (<a href="/recipes/tags/check/">check</a>, <a href="/recipes/tags/checker/">checker</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/root/">root</a>, <a href="/recipes/tags/square/">square</a>). </p> <p>This program will take input from the user and either check if a number is a perfect square or square a number, depending on user's choice.</p>

2014-08-18T05:01:04-07:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578924-2d-fluid-simulation-using-fhp-lgca/

<p style="color: grey"> Python recipe 578924 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/physics/">physics</a>, <a href="/recipes/tags/simulation/">simulation</a>). </p> <p>2D Fluid Simulation using FHP LGCA (Lattice Gas Cellular Automata)</p> <p>Simulates fluid flow in a circular channel.</p> <p>It works really slow but I think it can be a lot faster if it modified for NumPy and possibly Py2Exe.</p> <p>But my main goal was to provide easy to understand code (not performance) anyway. </p>

2014-09-16T22:27:04-07:00Barry Walkerhttp://code.activestate.com/recipes/users/4177147/http://code.activestate.com/recipes/578934-a-fun-perfect-square-checker-using-integer-arithme/

<p style="color: grey"> Bash recipe 578934 by <a href="/recipes/users/4177147/">Barry Walker</a> (<a href="/recipes/tags/arithmetic/">arithmetic</a>, <a href="/recipes/tags/bash/">bash</a>, <a href="/recipes/tags/check/">check</a>, <a href="/recipes/tags/checker/">checker</a>, <a href="/recipes/tags/cygwin/">cygwin</a>, <a href="/recipes/tags/macbook_pro/">macbook_pro</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/perfect/">perfect</a>, <a href="/recipes/tags/root/">root</a>, <a href="/recipes/tags/square/">square</a>). </p> <p>A recent Python upload here gave me the inspiration to do a bash version... This is a little tongue-in-cheek but an enjoyable bit of fun.</p> <p>It took around 11 seconds to prove 90000000000 had a perfect square of 300000...</p> <p>It is a stand alone program and has a degree of INPUT error correction...</p> <p>It was done on a MacBook Pro, OSX 10.7.5, default bash terminal and should work on Linux flavours but it is untested...</p> <p>Enjoy finding simple solutions to often very difficult problems...</p> <p>Bazza...</p>

2012-05-14T13:34:31-07:00Anand B Pillaihttp://code.activestate.com/recipes/users/4169530/http://code.activestate.com/recipes/578131-a-simple-matrix-class/

<p style="color: grey"> Python recipe 578131 by <a href="/recipes/users/4169530/">Anand B Pillai</a> (<a href="/recipes/tags/algebra/">algebra</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/matrix/">matrix</a>). Revision 3. </p> <p>A simple class in Python representing a Matrix with basic operations, operator overloading and class factory methods to make Matrices from different sources.</p>

2014-05-16T02:40:28-07:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578881-automated-stock-market-trading-simulation/

<p style="color: grey"> Python recipe 578881 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/simulation/">simulation</a>, <a href="/recipes/tags/stock/">stock</a>, <a href="/recipes/tags/stock_market/">stock_market</a>). </p> <p>It simulates an automated trading strategy against a simulated stock.</p> <p>I think the results are interesting. It seems number of wins are always higher than number of losses but average amount of loss is also always higher than average amount of win! </p>

2013-08-29T06:11:41-07:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578652-voxel-based-ray-tracing/

<p style="color: grey"> Python recipe 578652 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/graphics/">graphics</a>, <a href="/recipes/tags/image/">image</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>). </p> <p>The standard ray tracing algorithm seems unnatural to me because everytime a ray reflects/refracts all (primitive) objects in the scene must be tested for intersection; no matter where they located!</p> <p>In this method there is no such thing. It just moves each ray voxel by voxel until it hits an opaque/reflective(/refractive) voxel.</p> <p>I made many simplifications so the image is crude.</p>

2013-09-02T18:49:53-07:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578653-calculating-e-using-continued-fraction/

<p style="color: grey"> Python recipe 578653 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>). </p> <p>Calculating e using Continued Fraction</p>

2013-08-25T06:24:56-07:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578651-calculating-pi-using-trigonometric-iterations/

<p style="color: grey"> Python recipe 578651 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/pi/">pi</a>). </p> <p>Calculating PI using trigonometric iterations</p>

2013-06-09T06:09:52-07:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578555-relativistic-rocket-kinematics/

<p style="color: grey"> Python recipe 578555 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/physics/">physics</a>). </p> <p>Relativistic Rocket Kinematics</p>

2013-01-16T16:39:08-08:00Captain DeadBoneshttp://code.activestate.com/recipes/users/4184772/http://code.activestate.com/recipes/578418-fixed-point-iteration-in-python/

<p style="color: grey"> Python recipe 578418 by <a href="/recipes/users/4184772/">Captain DeadBones</a> (<a href="/recipes/tags/fixed_point/">fixed_point</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/python/">python</a>). </p> <p>The code utilizes fixed point iteration to solve equations in python. This code was wrriten for <a href="http://thelivingpearl.com/2013/01/15/the-easy-way-to-solve-equations-in-python/">How to solve equations using python</a>.</p>

2013-02-23T04:00:52-08:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578469-bilinear-interpolation/

<p style="color: grey"> Python recipe 578469 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/graphics/">graphics</a>, <a href="/recipes/tags/image/">image</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/pil/">pil</a>). </p> <p>Creates a surface from a grid of random numbers using Bilinear Interpolation.</p>

2012-12-17T06:04:19-08:00FB36http://code.activestate.com/recipes/users/4172570/http://code.activestate.com/recipes/578382-knights-tour-using-warnsdorff-algorithm/

<p style="color: grey"> Python recipe 578382 by <a href="/recipes/users/4172570/">FB36</a> (<a href="/recipes/tags/algorithm/">algorithm</a>, <a href="/recipes/tags/algorithms/">algorithms</a>, <a href="/recipes/tags/math/">math</a>, <a href="/recipes/tags/mathematics/">mathematics</a>). </p> <p>Knight's Tour using Warnsdorff Algorithm.</p>

2013-01-16T16:37:33-08:00Captain DeadBoneshttp://code.activestate.com/recipes/users/4184772/http://code.activestate.com/recipes/578417-bisection-method-in-python/

<p style="color: grey"> Python recipe 578417 by <a href="/recipes/users/4184772/">Captain DeadBones</a> (<a href="/recipes/tags/bisect/">bisect</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/python/">python</a>). </p> <p>This is a quick way to do bisection method in python. I wrote his code as part of an article, <a href="http://thelivingpearl.com/2013/01/15/the-easy-way-to-solve-equations-in-python/">How to solve equations using python</a></p>

2012-07-28T07:21:49-07:00Paddy McCarthyhttp://code.activestate.com/recipes/users/398009/http://code.activestate.com/recipes/578227-generate-the-parity-or-sign-of-a-permutation/

<p style="color: grey"> Python recipe 578227 by <a href="/recipes/users/398009/">Paddy McCarthy</a> (<a href="/recipes/tags/determinants/">determinants</a>, <a href="/recipes/tags/mathematics/">mathematics</a>, <a href="/recipes/tags/matrix/">matrix</a>, <a href="/recipes/tags/permutations/">permutations</a>). </p> <p>The <a href="http://en.wikipedia.org/wiki/Parity_of_a_permutation">parity</a> of a given permutation is whether an odd or even number of swaps between any two elements are needed to transform the given permutation to the first permutation.</p> <p>The sign of the permutation is +1 for an even parity and -1 for an odd parity.</p> <p>This python function returns the sign of a permutation of all the integers 0..N. When the program is run it shows the sign of permutations as generated by the standard function itertools.permutations.</p> <p>The function uses a modified <a href="http://rosettacode.org/wiki/Sorting_algorithms/Selection_sort#Python">selection sort</a> to compute the parity.</p>