Mark Overmeer > POSIX-1003-0.98 > POSIX::1003::Math

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NAME ^

POSIX::1003::Math - POSIX handling time

INHERITANCE ^

 POSIX::1003::Math
   is a POSIX::1003::Module

SYNOPSIS ^

  use POSIX::1003::Math qw/ceil floor sqrt/;
  print ceil 3.14;
  print sqrt floor 4.9;

DESCRIPTION ^

Be aware that math in Perl has unclear precission! Be aware that the math library often provides many variations of these functions... it is hard to determine which one is used. Probably, Math::Trig will serve you better. Or PDL for real number crunchers.

Be warned that these functions do not have an obligatory scalar parameter, but only an optional parameter (defaults to $_). This means that they have the lowest (is list) priority.

See documentation in the base class.

METHODS ^

See documentation in the base class.

POSIX::1003::Math->exampleValue(NAME)

See "METHODS" in POSIX::1003::Module

$obj->import()

See "METHODS" in POSIX::1003::Module

FUNCTIONS ^

Standard POSIX via this module (via POSIX.xs)

Like the built-in sin, cos, and sqrt, the EXPR defaults to $_ and there is a scalar context (missing from POSIX.pm).

acos(EXPR)
asin(EXPR)
atan(EXPR)
ceil(EXPR)
cosh(EXPR)
div(NUMER, DENOM)

Devide NUMER by DENOminator. The result is a list of two: quotient and remainder. Implemented in Perl for completeness, currently not with the speed of XS.

  my ($quotient, $remainder) = div($number, $denom);
floor(EXPR)
fmod(EXPR, EXPR)
frexp(EXPR)
ldexp(EXPR)
log10(EXPR)
modf(EXPR, EXPR)
pow(EXPR1, EXPR2)

Returns EXPR1 ** EXPR2

rint(NUMBER)

Round to the closest integer. Implemented in Perl for completeness.

sinh(EXPR)
tan(EXPR)
tanh(EXPR)

Standard POSIX, using CORE

A small set of mathematical functions are available in Perl CORE, without the need to load this module. But if you do import them, it simply gets ignored.

abs([EXPR])
atan2(EXPR, EXPR)
cos([EXPR])
exp([EXPR])
log([EXPR])
rand([EXPR])
sin([EXPR])
sqrt([EXPR])
srand([EXPR])

Numeric conversions

All strto*, atof, atoi and friends functions are usually not needed in Perl programs: the integer and float types are at their largest size, so when a string is used in numeric context it will get converted automatically. Still, POSIX.xs does provide a few of those functions, which are sometimes more accurate in number parsing for large numbers.

All three provided functions treat errors the same way. Truly POSIX-compliant systems set $ERRNO ($!) to indicate a translation error, so clear $! before calling strto*. Non-compliant systems may not check for overflow, and therefore will never set $!.

To parse a string $str as a floating point number use

  $! = 0;
  ($num, $n_unparsed) = strtod($str);

  if($str eq '' || $n_unparsed != 0 || $!) {
      die "Non-numeric input $str" . ($! ? ": $!\n" : "\n");
  }

  # When you do not care about handling errors, you can do
  $num = strtod($str);
  $num = $str + 0;     # same: Perl auto-converts
strtod(STRING)

String to double translation. Returns the parsed number and the number of characters in the unparsed portion of the string. When called in a scalar context strtod returns the parsed number.

strtol(STRING, BASE)

String to integer translation. Returns the parsed number and the number of characters in the unparsed portion of the string. When called in a scalar context strtol returns the parsed number.

The base should be zero or between 2 and 36, inclusive. When the base is zero or omitted strtol will use the string itself to determine the base: a leading "0x" or "0X" means hexadecimal; a leading "0" means octal; any other leading characters mean decimal. Thus, "1234" is parsed as a decimal number, "01234" as an octal number, and "0x1234" as a hexadecimal number.

strtoul(STRING, BASE)

String to unsigned integer translation, which behaves like strtol.

CONSTANTS ^

The following constants are exported, shown here with the values discovered during installation of this module:

  CHAR_BIT         8
  CHAR_MAX         127
  CHAR_MIN         -128
  DBL_DIG          15
  DBL_EPSILON      2.22044604925031e-16
  DBL_MANT_DIG     53
  DBL_MAX          1.79769313486232e+308
  DBL_MAX_10_EXP   308
  DBL_MAX_EXP      1024
  DBL_MIN          2.2250738585072e-308
  DBL_MIN_10_EXP   -307
  DBL_MIN_EXP      -1021
  FLT_DIG          6
  FLT_EPSILON      1.19209289550781e-07
  FLT_MANT_DIG     24
  FLT_MAX          3.40282346638529e+38
  FLT_MAX_10_EXP   38
  FLT_MAX_EXP      128
  FLT_MIN          1.17549435082229e-38
  FLT_MIN_10_EXP   -37
  FLT_MIN_EXP      -125
  FLT_RADIX        2
  FLT_ROUNDS       1
  HUGE_VAL         inf
  INT_MAX          2147483647
  INT_MIN          -2147483648
  LDBL_DIG         18
  LDBL_EPSILON     undef
  LDBL_MANT_DIG    64
  LDBL_MAX         undef
  LDBL_MAX_10_EXP  4932
  LDBL_MAX_EXP     16384
  LDBL_MIN         undef
  LDBL_MIN_10_EXP  -4931
  LDBL_MIN_EXP     -16381
  LONG_MAX         9223372036854775807
  LONG_MIN         -9223372036854775808
  RAND_MAX         2147483647
  SCHAR_MAX        127
  SCHAR_MIN        -128
  SHRT_MAX         32767
  SHRT_MIN         -32768
  UCHAR_MAX        255
  UINT_MAX         4294967295
  ULONG_MAX        18446744073709551615
  USHRT_MAX        65535

SEE ALSO ^

This module is part of POSIX-1003 distribution version 0.98, built on December 03, 2013. Website: http://perl.overmeer.net. The code is based on POSIX, which is released with Perl itself. See also POSIX::Util for additional functionality.

COPYRIGHTS ^

Copyrights 2011-2013 on the perl code and the related documentation by [Mark Overmeer]. For other contributors see ChangeLog.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See http://www.perl.com/perl/misc/Artistic.html

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