Website last updated 03 August, 2010

CIF Scale

This is the inverted version of the pi-folded CF scale

It's found on the slider, and its counterpart DIF is found on the stock. Otherwise they are identical and everything we say about CIF applies to DIF.

CIF is used primarily for performing efficient multiplications using CF and DF.

CIF is not itself folded at pi, rather at 1/pi, so it will cause errors to assume CIF means the "CI scale folded at pi", especially because pi and 1/pi are very close on the slide rule. Remember it as the "Inverted CF scale".(CFI would be a better name.)

This warning doesn't apply to CIF_10. Because that scale is folded at sqrt(10) - the exact center of the decade - it is both the inverted CF_10 scale and the CI scale folded at root 10.

read tutorial on folded scales

read tutorial on inverted scales