Octave

GNU Octave is a free language for numerical computing, written to run MATLAB programs with few or no changes. Work on it began in 1988, as companion software for a chemical engineering textbook, and the first public release came in 1993. Like MATLAB, it’s still used in engineering and signal processing courses.

Every value is an array, and arithmetic works on whole arrays at once: values - m subtracts from every element, and A * v is a matrix product. Octave also ships many of the methods themselves, such as mean, var, polyfit, and eig. The from-scratch versions here write those out. The Octave Forge packages, such as statistics with its kmeans, aren’t installed.

Quirks

• * and ^ are matrix operations. [1 2 3] .^ 2 squares each element and gives 1 4 9; [1 2 3] ^ 2 is an error, because only a square matrix has a power.
• Arrays count from 1, and v(end) is the last element. v(0) is an error.
• Dividing integers rounds to the nearest whole number: int32(7) / 2 is 4, and int32(-7) / 2 is −4. idivide truncates instead, giving 3.
• A line without a semicolon prints its result, so x = 5 shows x = 5. Every line here ends with a semicolon unless it prints on purpose.

git clone https://github.com/qnixon/dswithx.git
cd dswithx
python3 harness/run_tests.py --language octave