code: public boolean checkScaleMatrixConsistency(Matrix4d scaleMatrix) {
  
  		double vol = getVolume();
  		Matrix3d m = new Matrix3d();
  		scaleMatrix.getRotationScale(m);
  
  		// note we need to have a relaxed tolerance here as the PDB scale matrix is given with not such high precision
  		// plus we don't want to have false positives, so we stay conservative
  		double tolerance = vol/100.0;
  		if ((Math.abs(vol - 1.0/m.determinant() )>tolerance)) {
  			//System.err.println("Warning! SCALE matrix from PDB does not match 1/determinat == cell volume: "+
  			//		String.format("vol=%6.3f  1/det=%6.3f",vol,1.0/m.determinant()));
  			return false;
  		}
  		// this would be to check our own matrix, must always match!
  		//if (!deltaComp(vol,1.0/getMTranspose().determinant())) {
  		//	System.err.println("Our calculated SCALE matrix does not match 1/det=cell volume");
  		//}
  
  		return true;
  
  	}
docs: Given a scale matrix parsed from the PDB entry (SCALE1,2,3 records),
  checks that the matrix is a consistent scale matrix by comparing the
  cell volume to the inverse of the scale matrix determinant (tolerance of 1/100).
  If they don't match false is returned.
  See the PDB documentation for the SCALE record.
  See also last equation of section 2.5 of "Fundamentals of Crystallography" C. Giacovazzo
  @param scaleMatrix
  @return