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# Donald Munro donaldmunro

Created November 20, 2021 16:33
View sage-ext.md
``````clear_vars
reset()
%display latex

u,v,w,T = SR.var('x y z t')
E_x,E_y,E_z  = function('Ex'),function('Ey'), function('Ez')
B_x,B_y,B_z  = function('Bx'),function('By'), function('Bz')
M.<t, x, y, z> = manifolds.Minkowski(positive_spacelike=False)
F = M.diff_form(2, name='F')
``````
Last active August 3, 2021 22:44
Differential Forms on simple Euclidean manifolds using SageMath Manifolds package
View euclidean_forms.md
``````clear_vars
reset()
%display latex
R3 = Manifold(3, 'R^3', start_index=1)
X.<x,y,z> = R3.chart()
g = R3.metric('g')
g[1,1], g[2,2], g[3,3] = 1, 1, 1

#R2 = Manifold(2, 'R^2', ambient=R3, start_index=1)
``````
Created January 26, 2019 22:58
A wrapped std::multimap which limits size by removing the smallest keys first. Useful for timestamped data where the oldest items (smallest timestamps) can be removed.
View bounded_map.h
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 #ifndef _BOUNDED_MAP_H #define _BOUNDED_MAP_H #include #include #include #include /** * A wrapped std::multimap which limits size by removing the smallest keys first.
Created January 28, 2018 16:33
View kotlin-jni-javah.sh
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 # Using javah to generate .h files for Kotlin # Assuming JNI function calls are in MainActivity.companion STUDIO=/opt/android-studio PACKAGE=my.package \$STUDIO/jre/bin/javah -jni -cp "\$STUDIO/lib/kotlin-runtime.jar:build/tmp/kotlin-classes/debug" \$PACKAGE.MainActivity.Companion
Last active January 18, 2023 22:25
Compile Boost for Android
View boost-android.md

# Compiling Boost for Android

1. Download Boost and cd to base directory.

2. Create Android toolchains for desired architectures by running a script as below:

```NDK=/opt/android-sdk/ndk-bundle/
TOOLCHAINS="\$PWD/toolchains/"```

rm -rf \$TOOLCHAINS

Created March 5, 2017 14:05
Access/dereference glm::mat4 contents
View gist:a2a0a061de498b9dc0ec10be309de2b7
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 #include .. glm::mat4 m = glm::mat4(1.0f); .. auto p = glm::value_ptr(m); std::cout << sizeof(p) << std::endl; glUniformMatrix4fv(shader_uniform_m, 1, GL_FALSE, p);
Created March 5, 2017 13:26
Display/print a GLM mat or vec
View gist:38841d72c65a1c32f2bf83a4a00a2c9a
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 #include .. .. glm::mat4 mat; .. .. std::cout << glm::to_string(mat) << std::endl;
Created February 25, 2017 21:11
Parse delimited string in C++
View gist:afa2f57bd4e52aa3cc0e3bbe422c889e
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 size_t split(std::string s, std::vector& tokens, std::string delim ="\t\n ") { tokens.clear(); size_t pos = s.find_first_not_of(delim); while (pos != std::string::npos) { size_t next = s.find_first_of(delim, pos); if (pos == std::string::npos) tokens.emplace_back(s.substr(pos));
Created February 24, 2017 16:58
Map OpenCv Mat to Eigen Matrix and calculate Eigenvectors
View gist:beb7f226adf9c585c67f2599384e43ab
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 #include #include .. .. using RowMatrixXf = Eigen::Matrix; Eigen::Map mapped(extended_homograpy.ptr(), homography.rows, homography.cols); Eigen::EigenSolver eigen_solve(mapped, true); auto ev = eigen_solve.eigenvectors(); std::cout << "No of EigenVectors = " << ev.cols() << std::endl; for (auto i=0; i
Last active January 10, 2016 12:08
Benchmark OpenCV Feature/Descriptor Extractors.
View features.cc
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 /* Copyright (c) 2016, Donald Munro Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR