#include "cdflib.h" double spmpar(int *i) /* ----------------------------------------------------------------------- SPMPAR PROVIDES THE SINGLE PRECISION MACHINE CONSTANTS FOR THE COMPUTER BEING USED. IT IS ASSUMED THAT THE ARGUMENT I IS AN INTEGER HAVING ONE OF THE VALUES 1, 2, OR 3. IF THE SINGLE PRECISION ARITHMETIC BEING USED HAS M BASE B DIGITS AND ITS SMALLEST AND LARGEST EXPONENTS ARE EMIN AND EMAX, THEN SPMPAR(1) = B**(1 - M), THE MACHINE PRECISION, SPMPAR(2) = B**(EMIN - 1), THE SMALLEST MAGNITUDE, SPMPAR(3) = B**EMAX*(1 - B**(-M)), THE LARGEST MAGNITUDE. ----------------------------------------------------------------------- WRITTEN BY ALFRED H. MORRIS, JR. NAVAL SURFACE WARFARE CENTER DAHLGREN VIRGINIA ----------------------------------------------------------------------- ----------------------------------------------------------------------- MODIFIED BY BARRY W. BROWN TO RETURN DOUBLE PRECISION MACHINE CONSTANTS FOR THE COMPUTER BEING USED. THIS MODIFICATION WAS MADE AS PART OF CONVERTING BRATIO TO DOUBLE PRECISION ----------------------------------------------------------------------- */ { static int K1 = 4; static int K2 = 8; static int K3 = 9; static int K4 = 10; static double spmpar,b,binv,bm1,one,w,z; static int emax,emin,ibeta,m; /* .. .. Executable Statements .. */ if(*i > 1) goto S10; b = ipmpar(&K1); m = ipmpar(&K2); spmpar = pow(b,(double)(1-m)); return spmpar; S10: if(*i > 2) goto S20; b = ipmpar(&K1); emin = ipmpar(&K3); one = 1.0; binv = one/b; w = pow(b,(double)(emin+2)); spmpar = w*binv*binv*binv; return spmpar; S20: ibeta = ipmpar(&K1); m = ipmpar(&K2); emax = ipmpar(&K4); b = ibeta; bm1 = ibeta-1; one = 1.0; z = pow(b,(double)(m-1)); w = ((z-one)*b+bm1)/(b*z); z = pow(b,(double)(emax-2)); spmpar = w*z*b*b; return spmpar; } /* END */