# Mapper Library This module provides efficient implementations of commonly used operator representation mapper routines. ## Python wrappers The functions below are thin, type-agnostic convenience mappers. Each delegates to the appropriate library implementation below under the hood, based on the type of the object it is given. They do not implement any conversion logic themselves. ## Library implementations The functions below are the native, efficient mapper implementations backing this module. ## Ternary-tree encodings These map an operator through a ternary-tree encoding, which is built with [`TernaryTree`](../stubs/qiskit_fermions.mappers.TernaryTree.html.md#qiskit_fermions.mappers.TernaryTree) and [`TernaryTreeEncoding`](../stubs/qiskit_fermions.mappers.TernaryTreeEncoding.html.md#qiskit_fermions.mappers.TernaryTreeEncoding) from the [`mappers`](qiskit_fermions.mappers.html.md#module-qiskit_fermions.mappers) framework module. Compile a tree once and reuse the encoding across every operator mapped through it. The type-agnostic [`ternary_tree()`](../stubs/qiskit_fermions.mappers.library.ternary_tree.html.md#qiskit_fermions.mappers.library.ternary_tree) wrapper dispatches to these.