@spiceErrorCheck<EOL>def twovec(axdef, indexa, plndef, indexp):
axdef = stypes.toDoubleVector(axdef)<EOL>indexa = ctypes.c_int(indexa)<EOL>plndef = stypes.toDoubleVector(plndef)<EOL>indexp = ctypes.c_int(indexp)<EOL>mout = stypes.emptyDoubleMatrix()<EOL>libspice.twovec_c(axdef, indexa, plndef, indexp, mout)<EOL>return stypes.cMatrixToNumpy(mout)<EOL>
Find the transformation to the right-handed frame having a
given vector as a specified axis and having a second given
vector lying in a specified coordinate plane.

http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/twovec_c.html

:param axdef: Vector defining a principal axis.
:type axdef: 3-Element Array of floats
:param indexa: Principal axis number of axdef (X=1, Y=2, Z=3).
:type indexa: int
:param plndef: Vector defining (with axdef) a principal plane.
:type plndef: 3-Element Array of floats
:param indexp: Second axis number (with indexa) of principal plane.
:type indexp: int
:return: Output rotation matrix.
:rtype: 3x3-Element Array of floats