README.rst

Matlab Utils

This is a github repo where I'm going to keep non-company specific MATLAB tools that I whip up.

functools

The functools package is a collection of utility functions for working in MATLAB in a more functional style.

Testing requires matlab-xunit.

Examples

Each function is documented individually. The contents of the test file should be enough to give you an idea of how things work:

function test_system
    % Test a few components at once.

    join = @(sep, args) ...
        functools.if(ischar(sep), @() ... % Input check
            functools.reduce(@(x, y) [x sep y], ... % Reduce to string
                functools.map(@num2str, args))); % Convert args to string.

    assertEqual(join({'Not a string'}, {1, 2, 3, 4}), []);
    assertEqual(join(', ', {1, 2, 3, 4}), '1, 2, 3, 4');
    assertEqual(join('+', {'A', 2, 'x'}), 'A+2+x');

    % This is a profoundly stupid way of doing things, but it's good for
    % demonstration.
    ghettosum = functools.compose(...
        functools.partial(join, '+'), @eval);

    assertEqual(ghettosum({1, 2, 3, 4, 5, 6}), 21);
    % => eval(join('+', {1, 2, 3, 4, 5, 6}))
end

function test_reduce
    assertEqual(10, functools.reduce(@(x, y) x + y, [1, 2, 3, 4]))
    assertEqual(11, functools.reduce(@(x, y) x + y, [1, 2, 3, 4], 1))
end

function test_compose
    nth_even = functools.compose(@(x) x - 1, @(x) x * 2);
    assertEqual(nth_even(1), 0);
    assertEqual(nth_even(2), 2);
    assertEqual(nth_even(3), 4);
end

function test_apply
    adder = @(x, y) x + y;
    sum = functools.partial(@functools.reduce, adder);
    sumargs = @(varargin) sum(varargin);

    assertEqual(sumargs(1, 2, 3, 4), 10);
    assertEqual(functools.apply(sumargs, [1, 2, 3, 4]), 10);
end

function test_partial
    a = 1;
    b = ones(2, 1) / 2;
    movingavg2 = functools.partial(@filter, b, a);
    assertElementsAlmostEqual(movingavg2(1:4), [0.5, 1.5, 2.5, 3.5], 'absolute', 6);

    movingavg2 = functools.partial(@filter, b);
    assertElementsAlmostEqual(movingavg2(a, 1:4), [0.5, 1.5, 2.5, 3.5], 'absolute', 6);

end

function test_rpartial_more
    map = functools.rpartial(@cellfun, 'UniformOutput', false);
    assertEqual(map(@(x) x + 2, {-1, 0, 1, 2}), {1 2 3 4});
end

function test_rpartial
    isodate = functools.rpartial(@datestr, 'yyyy-mm-dd HH:MM:SS');
    assertEqual(isodate(datenum(2010, 1, 1)), '2010-01-01 00:00:00');
end

function test_map
    res = functools.map(@(x) x * 2, {1, 2, 3});
    assertEqual(cell2mat(res), [2, 4, 6]);
    functools.map(@fprintf, {'functools.map ', 'is ', 'working'});
end

function test_if
    assertEqual(functools.if(true, @() 'Hello'), 'Hello');
    assertEqual(functools.if(false, @() 'Hello'), []);
    assertEqual(functools.if(false, @() 'Hello', @() 'Goodbye'), 'Goodbye');
    assertEqual(functools.if(true, @(msg) msg, @(msg) msg, {'Hello'}), 'Hello');
    assertEqual(functools.if(false, @(msg) msg, @(msg) msg, {'Goodbye'}), 'Goodbye');
    assertEqual(functools.if(false, @(msg) msg, {'Hello'}, @(msg) msg, {'Goodbye'}), 'Goodbye');

    res = functools.if(true, ...
        @(n, m) ones(n, m), {4, 4}, ...
        @(n, m) fprintf('Could not make ones with dims %d, %d', n, m), {4, 4});

    assertEqual(size(res), [4 4]);
end