message: use memoize1 for getOperatorsCached333
diff: /**
  - * Copyright (c) 2017-2018 mol* contributors, licensed under MIT, See LICENSE file for more info.
  + * Copyright (c) 2017-2019 mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author David Sehnal <david.sehnal@gmail.com>
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  @@ -14,6 +14,7 @@ import Unit from './unit';
  import { EquivalenceClasses } from 'mol-data/util';
  import { Vec3 } from 'mol-math/linear-algebra';
  import { SymmetryOperator, Spacegroup, SpacegroupCell } from 'mol-math/geometry';
  +import { memoize1 } from 'mol-util/memoize';
  namespace StructureSymmetry {
  export function buildAssembly(structure: Structure, asmName: string) {
  @@ -106,12 +107,11 @@ function getOperators(symmetry: ModelSymmetry, ijkMin: Vec3, ijkMax: Vec3) {
  return operators;
  }
  -function getOperatorsCached333(symmetry: ModelSymmetry) {
  - const operators: SymmetryOperator[] = symmetry._operators_333 || [];
  - const { spacegroup } = symmetry;
  - if (operators.length === 0) {
  +const getOperatorsCached333 = memoize1((symmetry: ModelSymmetry) => {
  const ijkMin = Vec3.create(-3, -3, -3)
  const ijkMax = Vec3.create(3, 3, 3)
  + const operators: SymmetryOperator[] = [];
  + const { spacegroup } = symmetry;
  operators[0] = Spacegroup.getSymmetryOperator(spacegroup, 0, 0, 0, 0)
  for (let op = 0; op < spacegroup.operators.length; op++) {
  for (let i = ijkMin[0]; i < ijkMax[0]; i++) {
  @@ -124,10 +124,8 @@ function getOperatorsCached333(symmetry: ModelSymmetry) {
  }
  }
  }
  - symmetry._operators_333 = operators;
  - }
  return operators;
  -}
  +})
  function assembleOperators(structure: Structure, operators: ReadonlyArray<SymmetryOperator>) {
  const assembler = Structure.Builder();
  