Decimal(3tcl)						  Tcl Decimal Arithmetic Library					     Decimal(3tcl)

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NAME

       ::Decimal - General decimal arithmetic

SYNOPSIS

       package require Tcl  ?8.5?

       ::Decimal::fromstr string

       ::Decimal::tostr decimal

       ::Decimal::setVariable variable setting

       ::Decimal::add a b

       ::Decimal::+ a b

       ::Decimal::subtract a b

       ::Decimal::- a b

       ::Decimal::multiply a b

       ::Decimal::* a b

       ::Decimal::divide a b

       ::Decimal::/ a b

       ::Decimal::divideint a b

       ::Decimal::remainder a b

       ::Decimal::abs decimal

       ::Decimal::compare a b

       ::Decimal::max a b

       ::Decimal::maxmag a b

       ::Decimal::min a b

       ::Decimal::minmag a b

       ::Decimal::plus a

       ::Decimal::minus a

       ::Decimal::copynegate a

       ::Decimal::copysign a b

       ::Decimal::is-signed decimal

       ::Decimal::is-zero decimal

       ::Decimal::is-NaN decimal

       ::Decimal::is-infinite decimal

       ::Decimal::is-finite decimal

       ::Decimal::fma a b c

       ::Decimal::round_half_even decimal digits

       ::Decimal::round_half_up decimal digits

       ::Decimal::round_half_down decimal digits

       ::Decimal::round_down decimal digits

       ::Decimal::round_up decimal digits

       ::Decimal::round_floor decimal digits

       ::Decimal::round_ceiling decimal digits

       ::Decimal::round_05up decimal digits

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DESCRIPTION

       The  decimal  package provides decimal arithmetic support for both limited precision floating point and arbitrary precision floating point.
       Additionally, integer arithmetic is supported.

       More information and the specifications	on  which  this  package  depends  can	be  found  on  the  general  decimal  arithmetic  page	at
       http://speleotrove.com/decimal This package provides for:

       o      A new data type decimal which is represented as a list containing sign, mantissa and exponent.

       o      Arithmetic operations on those decimal numbers such as addition, subtraction, multiplication, etc...

       Numbers are converted to decimal format using the operation ::Decimal::fromstr.

       Numbers are converted back to string format using the operation ::Decimal::tostr.

EXAMPLES

       This  section shows some simple examples. Since the purpose of this library is to perform decimal math operations, examples may be the sim-
       plest way to learn how to work with it and to see the difference between using this package and sticking with expr. Consult the API section
       of this man page for information about individual procedures.

		  package require decimal

		  # Various operations on two numbers.
		  # We first convert them to decimal format.
		  set a [::Decimal::fromstr 8.2]
		  set b [::Decimal::fromstr .2]

		  # Then we perform our operations. Here we multiply
		  set c [::Decimal::* $a $b]

		  # Finally we convert back to string format for presentation to the user.
		  puts [::Decimal::tostr $c] ; # => will output 8.4

		  # Other examples
		  #
		  # Subtraction
		  set c [::Decimal::- $a $b]
		  puts [::Decimal::tostr $c] ; # => will output 8.0

		  # Why bother using this instead of simply expr?
		  puts 8.399999999999999 ; # => will output 8.399999999999999
		  puts 7.999999999999999 ; # => will output 7.999999999999999
		  # See http://speleotrove.com/decimal to learn more about why this happens.

API

       ::Decimal::fromstr string
	      Convert string into a decimal.

       ::Decimal::tostr decimal
	      Convert decimal into a string representing the number in base 10.

       ::Decimal::setVariable variable setting
	      Sets the variable to setting. Valid variables are:

	      o      rounding  -  Method  of  rounding	to  use during rescale. Valid methods are round_half_even, round_half_up, round_half_down,
		     round_down, round_up, round_floor, round_ceiling.

	      o      precision - Maximum number of digits allowed in mantissa.

	      o      extended - Set to 1 for extended mode. 0 for simplified mode.

	      o      maxExponent - Maximum value for the exponent. Defaults to 999.

	      o      minExponent - Minimum value for the exponent. Default to -998.

       ::Decimal::add a b

       ::Decimal::+ a b
	      Return the sum of the two decimals a and b.

       ::Decimal::subtract a b

       ::Decimal::- a b
	      Return the differnece of the two decimals a and b.

       ::Decimal::multiply a b

       ::Decimal::* a b
	      Return the product of the two decimals a and b.

       ::Decimal::divide a b

       ::Decimal::/ a b
	      Return the quotient of the division between the two decimals a and b.

       ::Decimal::divideint a b
	      Return a the integer portion of the quotient of the division between decimals a and b

       ::Decimal::remainder a b
	      Return the remainder of the division between the two decimals a and b.

       ::Decimal::abs decimal
	      Return the absolute value of the decimal.

       ::Decimal::compare a b
	      Compare the two decimals a and b, returning 0 if a == b, 1 if a > b, and -1 if a < b.

       ::Decimal::max a b
	      Compare the two decimals a and b, and return a if a >= b, and b if a < b.

       ::Decimal::maxmag a b
	      Compare the two decimals a and b while ignoring their signs, and return a if abs(a) >= abs(b), and b if abs(a) < abs(b).

       ::Decimal::min a b
	      Compare the two decimals a and b, and return a if a <= b, and b if a > b.

       ::Decimal::minmag a b
	      Compare the two decimals a and b while ignoring their signs, and return a if abs(a) <= abs(b), and b if abs(a) > abs(b).

       ::Decimal::plus a
	      Return the result from ::Decimal::+ 0 $a.

       ::Decimal::minus a
	      Return the result from ::Decimal::- 0 $a.

       ::Decimal::copynegate a
	      Returns a with the sign flipped.

       ::Decimal::copysign a b
	      Returns a with the sign set to the sign of the b.

       ::Decimal::is-signed decimal
	      Return the sign of the decimal.  The procedure returns 0 if the number is positive, 1 if it's negative.

       ::Decimal::is-zero decimal
	      Return true if decimal value is zero, otherwise false is returned.

       ::Decimal::is-NaN decimal
	      Return true if decimal value is NaN (not a number), otherwise false is returned.

       ::Decimal::is-infinite decimal
	      Return true if decimal value is Infinite, otherwise false is returned.

       ::Decimal::is-finite decimal
	      Return true if decimal value is finite, otherwise false is returned.

       ::Decimal::fma a b c
	      Return the result from first multiplying a by b and then adding c. Rescaling only occurs after completion of all operations. In this
	      way the result may vary from that returned by performing the operations individually.

       ::Decimal::round_half_even decimal digits
	      Rounds decimal to digits number of decimal points with the following rules: Round to the nearest. If equidistant, round so the final
	      digit is even.

       ::Decimal::round_half_up decimal digits
	      Rounds decimal to digits number of decimal points with the following rules: Round to the nearest. If equidistant, round up.

       ::Decimal::round_half_down decimal digits
	      Rounds decimal to digits number of decimal points with the following rules: Round to the nearest. If equidistant, round down.

       ::Decimal::round_down decimal digits
	      Rounds decimal to digits number of decimal points with the following rules: Round toward 0.  (Truncate)

       ::Decimal::round_up decimal digits
	      Rounds decimal to digits number of decimal points with the following rules: Round away from 0

       ::Decimal::round_floor decimal digits
	      Rounds decimal to digits number of decimal points with the following rules: Round toward -Infinity.

       ::Decimal::round_ceiling decimal digits
	      Rounds decimal to digits number of decimal points with the following rules: Round toward Infinity

       ::Decimal::round_05up decimal digits
	      Rounds decimal to digits number of decimal points with the following rules: Round zero or five away from 0. The  same  as  round-up,
	      except that rounding up only occurs if the digit to be rounded up is 0 or 5, and after overflow the result is the same as for round-
	      down.

BUGS, IDEAS, FEEDBACK
       This document, and the package it describes, will undoubtedly contain bugs and other problems.  Please report such in the category  Decimal
       of the Tcllib SF Trackers [http://sourceforge.net/tracker/?group_id=12883].  Please also report any ideas for enhancements you may have for
       either package and/or documentation.

KEYWORDS

       decimal, math, tcl

CATEGORY

       Mathematics

COPYRIGHT

       Copyright (c) 2011 Mark Alston <mark at beernut dot com>

math								       1.0.2							     Decimal(3tcl)