Improve docstring of mju_eig3.

PiperOrigin-RevId: 595380013
Change-Id: Ia3663c11ff1cd50a35d5d72ba01e09ff3d9054d0

doc/APIreference/functions.rst

@@ -2985,7 +2985,7 @@ mju_eig3
 
 .. mujoco-include:: mju_eig3
 
-Eigenvalue decomposition of symmetric 3x3 matrix.
+Eigenvalue decomposition of symmetric 3x3 matrix, mat = eigvec * diag(eigval) * eigvec'.
 
 .. _mju_boxQP:
 

include/mujoco/mujoco.h

@@ -1118,7 +1118,7 @@ MJAPI void mju_bandMulMatVec(mjtNum* res, const mjtNum* mat, const mjtNum* vec,
 // Address of diagonal element i in band-dense matrix representation.
 MJAPI int mju_bandDiag(int i, int ntotal, int nband, int ndense);
 
-// Eigenvalue decomposition of symmetric 3x3 matrix.
+// Eigenvalue decomposition of symmetric 3x3 matrix, mat = eigvec * diag(eigval) * eigvec'.
 MJAPI int mju_eig3(mjtNum eigval[3], mjtNum eigvec[9], mjtNum quat[4], const mjtNum mat[9]);
 
 // minimize 0.5*x'*H*x + x'*g  s.t. lower <= x <= upper, return rank or -1 if failed

introspect/functions.py

@@ -7368,7 +7368,7 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
                  ),
              ),
          ),
-         doc='Eigenvalue decomposition of symmetric 3x3 matrix.',
+         doc="Eigenvalue decomposition of symmetric 3x3 matrix, mat = eigvec * diag(eigval) * eigvec'.",  # pylint: disable=line-too-long
      )),
     ('mju_boxQP',
      FunctionDecl(