... more about the two sides of zero. I am not so sure what you are asking. If you have two floating point single precision values that are as close as they can be without being equal, the difference will be about 1e-7 times either value. If the actual value was, for example, 1e37 the difference could be 1e30. If the values were around 10, the difference would be around 1e-6. -- glen

...has a someone different use from INT. DINT and AINT are used when one wants to truncate the fractional part of a floating point value, but keep it in floating point form. The results if AINT(1e30) and INT(1e30) will likely be different (until 128 bit processors become popular). I still believe that DFLOAT(i) is easier to read than REAL(i,KIND(1.d0)), but I probably wouldn't use DINT ...

...endif !c write(6,100) a,c,r,error,flag if(error.gt.bb) then write(fff,100) a,c,r,error,flag bb=error endif count=count+1 if(abs(a).gt.1e30) goto 2 1 continue 2 continue print *,fff if(a.lt.0.) stop bb=0. a=-1e-30 goto 10 100 format(g14.7,2x,a11,2x,g14.7,2x,g14.7,2x,a)...

... nearest points. The Fortran 77 version has a call like: CALL SPLINE(X,Y,N,YP1,YPN,Y2) with X, Y, and Y2 dimensioned N. YP1 and YPN are the input first derivative at the end points, or 1e30 to set the second derivative to zero at the end for a natural spline. A newer version presumably doesn't need N, but should still need YP1 and YPN. -- glen

... Y'' values at the two nearest points. The Fortran 77 version has a call like: CALL SPLINE(X,Y,N,YP1,YPN,Y2) with X, Y, and Y2 dimensioned N. YP1 and YPN are the input first derivative at the end points, or 1e30 to set the second derivative to zero at the end for a natural spline. A newer version presumably doesn't need N, but should still need YP1 and YPN. -- glen