code: public static Map<double[], int[]> getTransformMap(BioAssemblyInfo bioassemblyInfo, Map<String, Integer> chainIdToIndexMap) {
  	    Map<Matrix4d, List<Integer>> matMap = new LinkedHashMap<>();
  		List<BiologicalAssemblyTransformation> transforms = bioassemblyInfo.getTransforms();
  		for (BiologicalAssemblyTransformation transformation : transforms) {
  			Matrix4d transMatrix = transformation.getTransformationMatrix();
  			String transChainId = transformation.getChainId();
  			if (!chainIdToIndexMap.containsKey(transChainId)){
  				continue;
  			}
  			int chainIndex = chainIdToIndexMap.get(transformation.getChainId());
  			if(matMap.containsKey(transMatrix)){
  				matMap.get(transMatrix).add(chainIndex);
  			}
  			else{
  				List<Integer> chainIdList = new ArrayList<>();
  				chainIdList.add(chainIndex);
  				matMap.put(transMatrix, chainIdList);
  			}
  		}
  
  	    Map<double[], int[]> outMap = new LinkedHashMap<>();
  		for (Entry<Matrix4d, List<Integer>> entry : matMap.entrySet()) {
  			outMap.put(convertToDoubleArray(entry.getKey()), CodecUtils.convertToIntArray(entry.getValue()));
  		}
  		return outMap;
  	}
docs: Convert a bioassembly information into a map of transform, chainindices it relates to.
  @param bioassemblyInfo  the bioassembly info object for this structure
  @param chainIdToIndexMap the map of chain ids to the index that chain corresponds to.
  @return the bioassembly information (as primitive types).