(* SAC Rational number definition module. *)

DEFINITION MODULE SACRN;


FROM MASSTOR IMPORT LIST;


PROCEDURE RIRNP(I,CL: LIST): LIST;
(*Rational interval rational number product.  I is an interval with
rational endpoints.  c is a rational number.  J is the interval I*c.*)


PROCEDURE RNABS(R: LIST): LIST;
(*Rational number absolute value.  R is a rational number.  S is the
absolute value of R.*)


PROCEDURE RNCEIL(RL: LIST): LIST;
(*Rational number, ceiling of.  r is a rational number.  a=CEILING(r), 
an integer.*)


PROCEDURE RNCOMP(R,S: LIST): LIST;
(*Rational number comparison.  R and S are rational numbers.
t=SIGN(R-S).*)


PROCEDURE RNDEN(R: LIST): LIST;
(*Rational number denominator.  R is a rational number.  b is the
denominator of R, a positive integer.*)


PROCEDURE RNDIF(R,S: LIST): LIST;
(*Rational number difference.  R and S are rational numbers.  T=R-S.*)


PROCEDURE RNDWR(R,NL: LIST);
(*Rational number decimal write.  R is a rational number.  n is a
non-negative integer.  R is approximated by a decimal fraction D with
n decimal digits following the decimal point and D is written in the
output stream.  The inaccuracy of the approximation is at most
(1/2)*10**-n.  If ABS(D) is greater than ABS(R) then the last digit is
followed by a minus sign, if ABS(D) is less than ABS(R) then by a
plus sign.*)


PROCEDURE RNFCL2(AL: LIST; VAR ML,NL: LIST);
(*Rational number floor and ceiling of logarithm, base 2.  a is a non-
zero rational number.  m=FLOOR(LOG2(ABS(a))) and n=CEILING(LOG2(ABS(a))) 
are gamma-integers.*)


PROCEDURE RNFLOR(RL: LIST): LIST;
(*Rational number, floor of.  r is a rational number.  a=FLOOR(r),
an integer.*)


PROCEDURE RNINT(A: LIST): LIST;
(*Rational number from integer.  A is an integer.  R is the rational
number A/1.*)


PROCEDURE RNINV(R: LIST): LIST;
(*Rational number inverse.  R is a non-zero rational number.  S=1/R.*)


PROCEDURE RNNEG(R: LIST): LIST;
(*Rational number negative.  R is a rational number.  S=-R.*)


PROCEDURE RNNUM(R: LIST): LIST;
(*Rational number numerator.  R is a rational number.  a is the
numerator of R, an integer.*)


PROCEDURE RNPROD(R,S: LIST): LIST;
(*Rational number product.  R and S are rational numbers.  T=R*S.*)


PROCEDURE RNP2(KL: LIST): LIST;
(*Rational number power of 2.  k is a gamma-integer.  r=2**k, a
rational number.*)


PROCEDURE RNQ(R,S: LIST): LIST;
(*Rational number quotient.  R and S are rational numbers, S non-zero.
T=R/S.*)


PROCEDURE RNRAND(NL: LIST): LIST;
(*Rational number, random.  n is a positive beta-integer.  Random
integers A and B are generated using IRAND(n).  Then R=A/(ABS(B)+1),
reduced to lowest terms.*)


PROCEDURE RNREAD(): LIST;
(*Rational number read.  The rational number R is read from the input
stream.  Any preceding blanks are skipped.*)


PROCEDURE RNRED(A,B: LIST): LIST;
(*Rational number reduction to lowest terms.  A and B are integers,
B non-zero.  R is the rational number A/B in canonical form.*)


PROCEDURE RNSIGN(R: LIST): LIST;
(*Rational number sign.  R is a rational number.  s=SIGN(R).*)


PROCEDURE RNSUM(R,S: LIST): LIST;
(*Rational number sum.  R and S are rational numbers.  T=R+S.*)


PROCEDURE RNWRIT(R: LIST);
(*Rational number write. R is a rational number.  R is converted 
to decimal and written in the output stream.*)


END SACRN.