@spiceErrorCheck<EOL>def vnorm(v):
v = stypes.toDoubleVector(v)<EOL>return libspice.vnorm_c(v)<EOL>
Compute the magnitude of a double precision, 3-dimensional vector.

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

:param v: Vector whose magnitude is to be found. 
:type v: 3-Element Array of floats
:return: magnitude of v calculated in a numerically stable way
:rtype: float