@spiceErrorCheck<EOL>def pxform(fromstr, tostr, et):
et = ctypes.c_double(et)<EOL>tostr = stypes.stringToCharP(tostr)<EOL>fromstr = stypes.stringToCharP(fromstr)<EOL>rotatematrix = stypes.emptyDoubleMatrix()<EOL>libspice.pxform_c(fromstr, tostr, et, rotatematrix)<EOL>return stypes.cMatrixToNumpy(rotatematrix)<EOL>
Return the matrix that transforms position vectors from one
specified frame to another at a specified epoch.

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

:param fromstr: Name of the frame to transform from.
:type fromstr: str
:param tostr: Name of the frame to transform to.
:type tostr: str
:param et: Epoch of the rotation matrix.
:type et: float
:return: A rotation matrix.
:rtype: 3x3 Element Array of floats