Decimal(n)              Tcl Decimal Arithmetic Library              Decimal(n)



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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
       simplest 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(n)
