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Some folks might think: “you still use RCS”?!? And we will say, hey, at least we switched from SCCS to RCS back in … I think it was around 1994 ... at least we are keeping up! :-) :-) :-) Logs say that SCCS version 18 became RCS version 19 on 1994 March 18. RCS served us well. But now it is time to move on. And so we are switching to git. Calc releases produce a lot of file changes. In the 125 releases of calc since 1996, when I started managing calc releases, there have been 15473 file mods!
123 lines
4.3 KiB
Plaintext
123 lines
4.3 KiB
Plaintext
NAME
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quomod - assign quotient and remainder to two lvalues
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SYNOPSIS
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quomod(x, y, Q, R [, rnd])
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TYPES
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x real
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y real
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Q null-or-real-valued lvalue with assign-to permission
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R null-or-real-valued lvalue with assign-to permission
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rnd nonnegative integer, defaults to config("quomod")
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return 0 or 1
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DESCRIPTION
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If y is nonzero and x/y is an integer q, this function assigns
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q to Q and zero to R, and returns zero.
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If y is zero, zero is assigned to Q, x to R and 0 or 1 returned
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according as x is zero or nonzero.
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In the remaining case, y nonzero and x/y not an intger, there
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are two pairs (q,r) for which x = q * y + r, q is an integer, and
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abs(r) < abs(y). Depending on the low 5 bits of rnd, the q and r
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of one of these pairs will be assigned to Q and R respectively,
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and the number 1 returned. The effects of rnd can be described in
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terms of the way q is related to x/y, e.g. by rounding down,
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rounding towards zero, rounding to a nearest integeri, etc. or
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by properties of the remainder r, e.g. positive, negative,
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smallest, etc. The effects of the most commonly used values of
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rnd are described in the following table:
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rnd q r
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0 round down. q = floor(x/y) same sign as y
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1 round up, q = ceil(x/y) opposite sign to y
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2 round to zero, q = int(x/y) same sign as x, r = y * frac(x/y)
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3 round from zero oppsite sign to x
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4 positive
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5 negative
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6 same sign as x/y
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7 opposite sigh to x/y
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8 to nearest even
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9 to nearest odd
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For 16 <= rnd < 32, the rounding is to the nearest integer and r
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is the smallest (in absolute value) remainder except when x/y is
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halfway between consecutive integers, in which case the rounding
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is as given by the 4 low bits of rnd. Using rnd = 24 gives the
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cpmmonly used principle of rounding: round to the nearest integer,
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but take the even integer when there are two equally close integers.
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For more detail on the effects of rnd for values other than those
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listed above, see "help quo" and "help mod".
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In all cases, the values assigned to Q and R by quomod(x, y, Q, R, rnd)
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are the same as those given by Q = quo(x,y,rnd), R = mod(x,y,rnd).
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If config("quo") == rnd, Q is also given by quo(x,y) or x // y.
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If config("mod") == rnd, R is also given by mod(x,y) or x % y.
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The rounding used by the C language for x / y and x % y corresponds
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to rnd = 2.
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An error values is returned and the values of Q and R are not changed
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if Q and R are not both lvalues, or if the current value of any
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argument is not as specified above, or if Q or R has no-assign-to
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prptection, e.g. after protect(Q,1).
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EXAMPLE
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; global u, v;
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; global mat M[2];
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; print quomod(13,5,u,v), u, v, quomod(15.6,5.2,M[0],M[1]), M[0], M[1];
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1 2 3 0 3 0
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; A = assoc();
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; print quomod(13, 5, A[1], A[2]), A[1], A[2]
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; 1 2 3
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; print quomod(10, -3, u, v), u, v;
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1 -4 -2
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; print quomod(10, -3, u, v, 0), u, v;
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1 -4 -2
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; print quomod(10, -3, u, v, 1), u, v;
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1 -3 1
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; print quomod(10, -3, u, v, 2), u, v;
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1 -3 1
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; print quomod(-10, -3, u, v, 2), u, v;
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1 3 -1
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LIMITS
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rnd < 2^31
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LINK LIBRARY
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BOOL qquomod(NUMBER *q1, NUMBER *q2, NUMBER **quo, NUMBER **mod)
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SEE ALSO
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//, %, quo, mod, floor. ceil, int. frac
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## Copyright (C) 1999-2006 Landon Curt Noll
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##
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## Calc is open software; you can redistribute it and/or modify it under
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## the terms of the version 2.1 of the GNU Lesser General Public License
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## as published by the Free Software Foundation.
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##
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## Calc is distributed in the hope that it will be useful, but WITHOUT
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## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
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## Public License for more details.
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##
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## A copy of version 2.1 of the GNU Lesser General Public License is
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## distributed with calc under the filename COPYING-LGPL. You should have
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## received a copy with calc; if not, write to Free Software Foundation, Inc.
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## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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##
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## Under source code control: 1995/05/07 03:17:03
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## File existed as early as: 1995
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##
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## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
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## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
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