2286	 Automatic Error Analysis for Determining Precision	 The problem considered is that of evaluating a rational expression to within any desired tolerance on a computer which performs variable-precision floating-point arithmetic operations. An automatic error analysis technique is given for determining directly from the results of a trial low-precision interval arithmetic calculation just how much precision and data accuracy are required to achieve a desired final accuracy. The technique given generalize easily to the evaluation of many nonrational expressions. error analysis interval arithmetic precision control
