Arithmetical method for digital differential analyzer

Abstract

A method of operation of a digital differential analyzer for performing the operation: ##EQU1## where Y is an integrand, .DELTA.Y is an increment of an input variable, R is a residue of the integrated value of the integrand, .DELTA.X is an increment of an independent variable, .DELTA.Z is an output increment of the integrated value of the integrand, K is a constant and n is an input number (a positive integer), in the ith iteration, uses a first mantissa M.sub.1, a second mantissa M.sub.2, a first exponent E.sub.1 and a second exponent E.sub.2 for expressing the abovementioned equation as follows, ##EQU2## then adjusts the radix points of the first and second mantissae in the bit number corresponding to the difference between the first and second exponents to adjust the mantissa portion to the greater exponent of the two, and thereafter calculates the mantissa portion to perform the abovementioned arithmetical operation and to obtain .DELTA.Z and R; the improvement wherein the mantissa portion of .DELTA.Z is expressed in terms of m (.gtoreq.2) bits by adding the most-significant bit corresponding to the first bit above the radix point to bits below the radix point and the radix point is then adjusted in accordance with the result of addition in order to obtain .DELTA.Z and R in accordance with the quantity of the result of addition for each iteration.