question: return the quantization error , this container stores concode_field_sep double qe concode_elem_sep Vector<InputDatum> inputs concode_elem_sep Vector<Unit> units concode_field_sep void setInputs concode_elem_sep void addMapUnit concode_elem_sep void setQE concode_elem_sep int getNumInputs concode_elem_sep String getInputLabel concode_elem_sep String getUnitCoords concode_elem_sep Unit getMapUnit concode_elem_sep void addInput concode_elem_sep void setMapUnits concode_elem_sep InputDatum getInput concode_elem_sep void clearMapUnits concode_elem_sep void clearInputs
target: double function ( ) { return this . qe ; }