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[Emacs-diffs] Changes to emacs/lispref/numbers.texi
From: |
Luc Teirlinck |
Subject: |
[Emacs-diffs] Changes to emacs/lispref/numbers.texi |
Date: |
Wed, 12 Nov 2003 16:31:16 -0500 |
Index: emacs/lispref/numbers.texi
diff -c emacs/lispref/numbers.texi:1.29 emacs/lispref/numbers.texi:1.30
*** emacs/lispref/numbers.texi:1.29 Sun Nov 2 01:29:58 2003
--- emacs/lispref/numbers.texi Wed Nov 12 16:30:14 2003
***************
*** 168,175 ****
@cindex negative infinity
@cindex infinity
@cindex NaN
! Most modern computers support the @acronym{IEEE} floating point standard,
which
! provides for positive infinity and negative infinity as floating point
values. It also provides for a class of values called NaN or
``not-a-number''; numerical functions return such values in cases where
there is no correct answer. For example, @code{(sqrt -1.0)} returns a
--- 168,175 ----
@cindex negative infinity
@cindex infinity
@cindex NaN
! Most modern computers support the @acronym{IEEE} floating point standard,
! which provides for positive infinity and negative infinity as floating point
values. It also provides for a class of values called NaN or
``not-a-number''; numerical functions return such values in cases where
there is no correct answer. For example, @code{(sqrt -1.0)} returns a
***************
*** 189,196 ****
@end table
In addition, the value @code{-0.0} is distinguishable from ordinary
! zero in @acronym{IEEE} floating point (although @code{equal} and @code{=}
consider
! them equal values).
You can use @code{logb} to extract the binary exponent of a floating
point number (or estimate the logarithm of an integer):
--- 189,196 ----
@end table
In addition, the value @code{-0.0} is distinguishable from ordinary
! zero in @acronym{IEEE} floating point (although @code{equal} and
! @code{=} consider them equal values).
You can use @code{logb} to extract the binary exponent of a floating
point number (or estimate the logarithm of an integer):
***************
*** 379,388 ****
@end defun
There are four functions to convert floating point numbers to integers;
! they differ in how they round. These functions accept integer arguments
! also, and return such arguments unchanged.
! @defun truncate number
This returns @var{number}, converted to an integer by rounding towards
zero.
--- 379,394 ----
@end defun
There are four functions to convert floating point numbers to integers;
! they differ in how they round. All accept an argument @var{number}
! and an optional argument @var{divisor}. Both arguments may be
! integers or floating point numbers. @var{divisor} may also be
! @code{nil}. If @var{divisor} is @code{nil} or omitted, these
! functions convert @var{number} to an integer, or return it unchanged
! if it already is an integer. If @var{divisor} is address@hidden, they
! divide @var{number} by @var{divisor} and convert the result to an
! integer. An @code{arith-error} results if @var{divisor} is 0.
! @defun truncate number &optional divisor
This returns @var{number}, converted to an integer by rounding towards
zero.
***************
*** 402,411 ****
This returns @var{number}, converted to an integer by rounding downward
(towards negative infinity).
! If @var{divisor} is specified, @code{floor} divides @var{number} by
! @var{divisor} and then converts to an integer; this uses the kind of
! division operation that corresponds to @code{mod}, rounding downward.
! An @code{arith-error} results if @var{divisor} is 0.
@example
(floor 1.2)
--- 408,415 ----
This returns @var{number}, converted to an integer by rounding downward
(towards negative infinity).
! If @var{divisor} is specified, this uses the kind of division
! operation that corresponds to @code{mod}, rounding downward.
@example
(floor 1.2)
***************
*** 421,427 ****
@end example
@end defun
! @defun ceiling number
This returns @var{number}, converted to an integer by rounding upward
(towards positive infinity).
--- 425,431 ----
@end example
@end defun
! @defun ceiling number &optional divisor
This returns @var{number}, converted to an integer by rounding upward
(towards positive infinity).
***************
*** 437,443 ****
@end example
@end defun
! @defun round number
This returns @var{number}, converted to an integer by rounding towards the
nearest integer. Rounding a value equidistant between two integers
may choose the integer closer to zero, or it may prefer an even integer,
--- 441,447 ----
@end example
@end defun
! @defun round number &optional divisor
This returns @var{number}, converted to an integer by rounding towards the
nearest integer. Rounding a value equidistant between two integers
may choose the integer closer to zero, or it may prefer an even integer,