def METHOD_NAME():
    import numpy as nm
    from sfepy.base.base import assert_
    import sfepy.mechanics.matcoefs as mc
    ok = True
    lam = 1.0
    mu = 4.0
    lam = nm.array([lam] * 3)
    mu = nm.array([mu] * 3)
    d = nm.array([[ 9.,  1.,  1.,  0.,  0.,  0.],
                  [ 1.,  9.,  1.,  0.,  0.,  0.],
                  [ 1.,  1.,  9.,  0.,  0.,  0.],
                  [ 0.,  0.,  0.,  4.,  0.,  0.],
                  [ 0.,  0.,  0.,  0.,  4.,  0.],
                  [ 0.,  0.,  0.,  0.,  0.,  4.]])
    _ds = mc.stiffness_from_lame(3, lam, mu)
    assert_(_ds.shape == (3, 6, 6))
    _ok = True
    for _d in _ds:
        __ok = nm.allclose(_d, d, rtol=0.0, atol=1e-14)
        _ok = _ok and __ok
    tst.report('stiffness_from_lame():', _ok)
    ok = ok and _ok
    _lam, _mu = mc.lame_from_stiffness(d)
    _ok = (_lam == 1) and (_mu == 4)
    tst.report('lame_from_stiffness():', _ok)
    ok = ok and _ok
    young = 1.0
    poisson = 0.25
    d = mc.stiffness_from_youngpoisson(3, young, poisson, plane='strain')
    _young, _poisson = mc.youngpoisson_from_stiffness(d, plane='strain')
    _ok = nm.allclose([young, poisson], [_young, _poisson],
                      rtol=0.0, atol=1e-14)
    tst.report('youngpoisson_from_stiffness(plane="strain"):', _ok)
    ok = ok and _ok
    d = mc.stiffness_from_youngpoisson(2, young, poisson, plane='stress')
    _young, _poisson = mc.youngpoisson_from_stiffness(d, plane='stress')
    _ok = nm.allclose([young, poisson], [_young, _poisson],
                      rtol=0.0, atol=1e-14)
    tst.report('youngpoisson_from_stiffness(plane="stress"):', _ok)
    ok = ok and _ok
    d = 4.0 / 3.0 * nm.array([[ 4., -2., -2.,  0.,  0.,  0.],
                              [-2.,  4., -2.,  0.,  0.,  0.],
                              [-2., -2.,  4.,  0.,  0.,  0.],
                              [ 0.,  0.,  0.,  3.,  0.,  0.],
                              [ 0.,  0.,  0.,  0.,  3.,  0.],
                              [ 0.,  0.,  0.,  0.,  0.,  3.]])
    _ds = mc.stiffness_from_lame_mixed(3, lam, mu)
    assert_(_ds.shape == (3, 6, 6))
    _ok = True
    for _d in _ds:
        __ok = nm.allclose(_d, d, rtol=0.0, atol=1e-14)
        _ok = _ok and __ok
    tst.report('stiffness_from_lame_mixed():', _ok)
    ok = ok and _ok
    blam = - mu * 2.0 / 3.0
    _ds = mc.stiffness_from_lame(3, blam, mu)
    assert_(_ds.shape == (3, 6, 6))
    _ok = True
    for _d in _ds:
        __ok = nm.allclose(_d, d, rtol=0.0, atol=1e-14)
        _ok = _ok and __ok
    tst.report('stiffness_from_lame() with modified lambda:', _ok)
    ok = ok and _ok
    assert ok