test_leastsquares.cpp

// Description: Testing for least-squares conformal affine transformation
// DocumentationOf: conformalaffine2d.h

#include "test/test_init.h"

#include "pastel/math/affine/affine_transformation.h"
#include "pastel/math/sampling/uniform_sampling.h"
#include "pastel/math/conformalaffine2d/conformalaffine2d_tools.h"
#include "pastel/math/conformalaffine2d/conformalaffine2d_least_squares.h"

#include "pastel/sys/locator.h"
#include "pastel/sys/vector/vector_tools.h"
#include "pastel/sys/set.h"

TEST_CASE("NoiselessSimilarity (LeastSquares)")
{
    for (integer points = 0;points < 1000;++points)
    {
        std::vector<Vector2> from;
        from.reserve(points);
        std::vector<Vector2> to;
        to.reserve(points);

        real scale = random<real>() * 0.9 + 0.1;
        real angle = random<real>() * 2 * constantPi<real>();
        Vector2 translation(random<real>() * 2 - 1, random<real>() * 2 - 1);

        if (points <= 1)
        {
            scale = 1;
            angle = 0;
        }

        if (points == 0)
        {
            translation = 0;
        }

        ConformalAffine2D<real> transformation(scale, angle, translation);

        for (integer j = 0;j < points;++j)
        {
            Vector2 fromPoint = randomVectorSphere<real, 2>();
            from.push_back(fromPoint);

            Vector2 toPoint = transformPoint(transformation, fromPoint);
            to.push_back(toPoint);
        }

        ConformalAffine2D<real> similarity =
            lsConformalAffine(from, to);

        REQUIRE(absoluteError<real>(similarity.scaling(), scale) <= 0.001);
        REQUIRE(absoluteError<real>(similarity.rotation(), angle) <= 0.001);
        REQUIRE(norm(similarity.translation() - translation) <= 0.001);
    }
}