## polymer

Gaussian-basis-set *ab initio* molecular-orbital and density-functional methods for molecules and crystals of one-, two-, or three-dimensional periodicity (two- and three-dimensional capabilities are untested). For molecules and helical polymers, supported methods are HF energy and gradients at zero & nonzero temperature; DFT energy and gradients at zero & nonzero temperature; MP2; GF2; CCSD; CIS & CIS-GF2; TDHF; TDDFT. For molecules only, additionally, general-order MP at zero & nonzero temperature; general-order CI; general-order CC; general-order EOM-CC; general-order IP/EA EOM-CC; general-order hole/particle CI; general-order GF; grid-based HF; grid-based MP2; OEP & TDOEP; dynamic polarizability at TDHF, TDDFT or TDOEP.

## tensor contraction engine

Tensor Contraction Engine (TCE) is a symbol algebra code written in Python, which derives working equations of *ab initio* electron-correlated theories and synthesizes the corresponding computer programs that execute in parallel as a part of NWCHEM or UTCHEM quantum chemistry software.

**Tutorial** (with audio; ~6 minutes)

## rubik

It enumerates all 3,674,160 configurations of 2x2x2 Rubik's Cube by performing all possible turns in each step, thereby determining its God's number (the minimal number of turns to solve the Cube in any initial configuration; the diameter of the Cayley graph of the Rubik's Cube group) in various metrics. It also reports the frequency of the appearances of duplicate configurations and the numbers of the turns used to reach all configurations. It also partially enumerates configurations of 3x3x3, 4x4x4, and 5x5x5 Rubik's Cubes.