Class: BigDecimal
Relationships & Source Files | |
Super Chains via Extension / Inclusion / Inheritance | |
Class Chain:
self,
::Numeric
|
|
Instance Chain:
self,
::Numeric
|
|
Inherits: |
Numeric
|
Defined in: | ext/bigdecimal/bigdecimal.c, ext/bigdecimal/bigdecimal.c, ext/bigdecimal/lib/bigdecimal/util.rb |
Overview
BigDecimal
provides arbitrary-precision floating point decimal arithmetic.
Introduction
Ruby provides built-in support for arbitrary precision integer arithmetic.
For example:
42**13 #=> 1265437718438866624512
BigDecimal
provides similar support for very large or very accurate floating point numbers.
Decimal arithmetic is also useful for general calculation, because it provides the correct answers people expect–whereas normal binary floating point arithmetic often introduces subtle errors because of the conversion between base 10 and base 2.
For example, try:
sum = 0
10_000.times do
sum = sum + 0.0001
end
print sum #=> 0.9999999999999062
and contrast with the output from:
require 'bigdecimal'
sum = BigDecimal("0")
10_000.times do
sum = sum + BigDecimal("0.0001")
end
print sum #=> 0.1E1
Similarly:
(BigDecimal("1.2") - BigDecimal("1.0")) == BigDecimal("0.2") #=> true
(1.2 - 1.0) == 0.2 #=> false
A Note About Precision
For a calculation using a BigDecimal and another value
, the precision of the result depends on the type of value
:
-
If
value
is a Float, the precision is Float::DIG + 1. -
If
value
is a Rational, the precision is larger thanFloat::DIG
+ 1. -
If
value
is a BigDecimal, the precision isvalue
‘s precision in the internal representation, which is platform-dependent. -
If
value
is other object, the precision is determined by the result of BigDecimal(value).
Special features of accurate decimal arithmetic
Because BigDecimal is more accurate than normal binary floating point arithmetic, it requires some special values.
Infinity
BigDecimal
sometimes needs to return infinity, for example if you divide a value by zero.
BigDecimal("1.0") / BigDecimal("0.0") #=> Infinity
BigDecimal("-1.0") / BigDecimal("0.0") #=> -Infinity
You can represent infinite numbers to BigDecimal
using the strings 'Infinity'
, '+Infinity'
and '-Infinity'
(case-sensitive)
Not a Number
When a computation results in an undefined value, the special value NaN
(for ‘not a number’) is returned.
Example:
BigDecimal("0.0") / BigDecimal("0.0") #=> NaN
You can also create undefined values.
NaN is never considered to be the same as any other value, even NaN itself:
n = BigDecimal('NaN')
n == 0.0 #=> false
n == n #=> false
Positive and negative zero
If a computation results in a value which is too small to be represented as a BigDecimal
within the currently specified limits of precision, zero must be returned.
If the value which is too small to be represented is negative, a BigDecimal
value of negative zero is returned.
BigDecimal("1.0") / BigDecimal("-Infinity") #=> -0.0
If the value is positive, a value of positive zero is returned.
BigDecimal("1.0") / BigDecimal("Infinity") #=> 0.0
(See .mode for how to specify limits of precision.)
Note that -0.0
and 0.0
are considered to be the same for the purposes of comparison.
Note also that in mathematics, there is no particular concept of negative or positive zero; true mathematical zero has no sign.
bigdecimal/util
When you require bigdecimal/util
, the #to_d method will be available on BigDecimal
and the native ::Integer
, ::Float
, ::Rational
, and ::String
classes:
require 'bigdecimal/util'
42.to_d # => 0.42e2
0.5.to_d # => 0.5e0
(2/3r).to_d(3) # => 0.667e0
"0.5".to_d # => 0.5e0
License
Copyright © 2002 by Shigeo Kobayashi <shigeo@tinyforest.gr.jp>.
BigDecimal
is released under the Ruby and 2-clause BSD licenses. See LICENSE.txt
for details.
Maintained by mrkn <mrkn@mrkn.jp> and ruby-core members.
Documented by zzak <zachary@zacharyscott.net>, mathew <meta@pobox.com>, and many other contributors.
Constant Summary
-
BASE =
Base value used in internal calculations. On a 32 bit system,
BASE
is 10000, indicating that calculation is done in groups of 4 digits. (If it were larger, BASE**2 wouldn’t fit in 32 bits, so you couldn’t guarantee that two groups could always be multiplied together without overflow.)INT2FIX((SIGNED_VALUE)VpBaseVal())
-
EXCEPTION_ALL =
Determines whether overflow, underflow or zero divide result in an exception being thrown. See .mode.
0xff
-
EXCEPTION_INFINITY =
Determines what happens when the result of a computation is infinity. See .mode.
0x01
-
EXCEPTION_NaN =
Determines what happens when the result of a computation is not a number (NaN). See .mode.
0x02
-
EXCEPTION_OVERFLOW =
Determines what happens when the result of a computation is an overflow (a result too large to be represented). See .mode.
0x01
-
EXCEPTION_UNDERFLOW =
Determines what happens when the result of a computation is an underflow (a result too small to be represented). See .mode.
0x04
-
EXCEPTION_ZERODIVIDE =
Determines what happens when a division by zero is performed. See .mode.
0x10
-
INFINITY =
Special value constants
BIGDECIMAL_POSITIVE_INFINITY
-
NAN =
# File 'ext/bigdecimal/bigdecimal.c', line 4535BIGDECIMAL_NAN
-
ROUND_CEILING =
Round towards +Infinity. See .mode.
5
-
ROUND_DOWN =
Indicates that values should be rounded towards zero. See .mode.
2
-
ROUND_FLOOR =
Round towards -Infinity. See .mode.
6
-
ROUND_HALF_DOWN =
Indicates that digits >= 6 should be rounded up, others rounded down. See .mode.
4
-
ROUND_HALF_EVEN =
Round towards the even neighbor. See .mode.
7
-
ROUND_HALF_UP =
Indicates that digits >= 5 should be rounded up, others rounded down. See .mode.
3
-
ROUND_MODE =
Determines what happens when a result must be rounded in order to fit in the appropriate number of significant digits. See .mode.
0x100
-
ROUND_UP =
Indicates that values should be rounded away from zero. See .mode.
1
-
SIGN_NEGATIVE_FINITE =
Indicates that a value is negative and finite. See #sign.
-2
-
SIGN_NEGATIVE_INFINITE =
Indicates that a value is negative and infinite. See #sign.
-3
-
SIGN_NEGATIVE_ZERO =
Indicates that a value is -0. See #sign.
-1
-
SIGN_NaN =
Indicates that a value is not a number. See #sign.
0
-
SIGN_POSITIVE_FINITE =
Indicates that a value is positive and finite. See #sign.
2
-
SIGN_POSITIVE_INFINITE =
Indicates that a value is positive and infinite. See #sign.
3
-
SIGN_POSITIVE_ZERO =
Indicates that a value is +0. See #sign.
1
-
VERSION =
The version of bigdecimal library
rb_str_new2(RUBY_BIGDECIMAL_VERSION)
Class Method Summary
-
._load(str)
Internal method used to provide marshalling support.
- .double_fig
- .interpret_loosely(str)
-
.limit(digits)
Limit the number of significant digits in newly created
BigDecimal
numbers to the specified value. -
.mode(mode, setting = nil) ⇒ Integer
Returns an integer representing the mode settings for exception handling and rounding.
-
.save_exception_mode
Execute the provided block, but preserve the exception mode.
-
.save_limit
Execute the provided block, but preserve the precision limit.
-
.save_rounding_mode
Execute the provided block, but preserve the rounding mode.
Instance Attribute Summary
-
#finite? ⇒ Boolean
readonly
Returns True if the value is finite (not NaN or infinite).
-
#infinite? ⇒ Boolean
readonly
Returns nil, -1, or 1 depending on whether the value is finite, -Infinity, or Infinity.
-
#nan? ⇒ Boolean
readonly
Returns True if the value is Not a Number.
-
#nonzero? ⇒ Boolean
readonly
Returns self if the value is non-zero, nil otherwise.
-
#zero? ⇒ Boolean
readonly
Returns True if the value is zero.
Instance Method Summary
- #%
- #*(r)
-
#**(other) ⇒ BigDecimal
Returns the BigDecimal value of
self
raised to powerother
: -
#+(value) ⇒ BigDecimal
Returns the BigDecimal sum of
self
andvalue
: -
#+ ⇒ self
Returns
self
: -
#-(value) ⇒ BigDecimal
Returns the BigDecimal difference of
self
andvalue
: -
#- ⇒ BigDecimal
Returns the BigDecimal negation of self:
- #/
-
#<(other) ⇒ Boolean
Returns
true
ifself
is less thanother
,false
otherwise: -
#<=(other) ⇒ Boolean
Returns
true
ifself
is less or equal to thanother
,false
otherwise: -
#<=>(r)
The comparison operator.
-
#==(r)
(also: #===, #eql?)
Tests for value equality; returns true if the values are equal.
-
#===(r)
Alias for #==.
-
#>(other) ⇒ Boolean
Returns
true
ifself
is greater thanother
,false
otherwise: -
#>=(other) ⇒ Boolean
Returns
true
ifself
is greater than or equal toother
,false
otherwise: -
#_dump ⇒ String
Returns a string representing the marshalling of
self
. -
#abs ⇒ BigDecimal
Returns the BigDecimal absolute value of
self
: -
#add(value, ndigits) ⇒ BigDecimal
Returns the BigDecimal sum of
self
andvalue
with a precision ofndigits
decimal digits. -
#ceil(n)
Return the smallest integer greater than or equal to the value, as a
BigDecimal
. -
#clone
Alias for #dup.
-
#coerce(other)
The coerce method provides support for Ruby type coercion.
-
#div(value) ⇒ Integer
Divide by the specified value.
-
#divmod(value)
Divides by the specified value, and returns the quotient and modulus as
BigDecimal
numbers. - #dup (also: #clone)
-
#eql?(r)
Alias for #==.
-
#exponent
Returns the exponent of the
BigDecimal
number, as an::Integer
. -
#fix
Return the integer part of the number, as a
BigDecimal
. -
#floor(n)
Return the largest integer less than or equal to the value, as a
BigDecimal
. -
#frac
Return the fractional part of the number, as a
BigDecimal
. -
#hash ⇒ Integer
Returns the integer hash value for
self
. -
#inspect
Returns a string representation of self.
- #modulo
-
#mult(other, ndigits) ⇒ BigDecimal
Returns the BigDecimal product of
self
andvalue
with a precision ofndigits
decimal digits. -
#n_significant_digits ⇒ Integer
Returns the number of decimal significant digits in
self
. -
#power(n)
Returns the value raised to the power of n.
-
#precision ⇒ Integer
Returns the number of decimal digits in
self
: -
#precision_scale ⇒ Array, Integer
Returns a 2-length array; the first item is the result of #precision and the second one is of #scale.
-
#precs ⇒ Array
Returns an Array of two
::Integer
values that represent platform-dependent internal storage properties. -
#quo(value) ⇒ BigDecimal
Divide by the specified value.
- #remainder
-
#round(n, mode)
Round to the nearest integer (by default), returning the result as a
BigDecimal
if n is specified, or as an::Integer
if it isn’t. -
#scale ⇒ Integer
Returns the number of decimal digits following the decimal digits in
self
. -
#sign
Returns the sign of the value.
-
#split
Splits a
BigDecimal
number into four parts, returned as an array of values. -
#sqrt(n)
Returns the square root of the value.
-
#sub(value, digits) ⇒ BigDecimal
Subtract the specified value.
-
#to_d ⇒ BigDecimal
Returns self.
-
#to_digits ⇒ String
Converts a
BigDecimal
to a::String
of the form “nnnnnn.mmm”. -
#to_f
Returns a new
::Float
object having approximately the same value as theBigDecimal
number. -
#to_i
(also: #to_int)
Returns the value as an
::Integer
. -
#to_int
Alias for #to_i.
-
#to_r
Converts a
BigDecimal
to a::Rational
. -
#to_s(s) ⇒ ?
Converts the value to a string.
-
#truncate(n)
Truncate to the nearest integer (by default), returning the result as a
BigDecimal
.
Class Method Details
._load(str)
Internal method used to provide marshalling support. See the Marshal module.
# File 'ext/bigdecimal/bigdecimal.c', line 802
static VALUE BigDecimal_load(VALUE self, VALUE str) { ENTER(2); Real *pv; unsigned char *pch; unsigned char ch; unsigned long m=0; pch = (unsigned char *)StringValueCStr(str); /* First get max prec */ while((*pch) != (unsigned char)'\0' && (ch = *pch++) != (unsigned char)':') { if(!ISDIGIT(ch)) { rb_raise(rb_eTypeError, "load failed: invalid character in the marshaled string"); } m = m*10 + (unsigned long)(ch-'0'); } if (m > VpBaseFig()) m -= VpBaseFig(); GUARD_OBJ(pv, VpNewRbClass(m, (char *)pch, self, true, true)); m /= VpBaseFig(); if (m && pv->MaxPrec > m) { pv->MaxPrec = m+1; } return VpCheckGetValue(pv); }
.double_fig
[ GitHub ].interpret_loosely(str)
[ GitHub ]# File 'ext/bigdecimal/bigdecimal.c', line 3752
static VALUE BigDecimal_s_interpret_loosely(VALUE klass, VALUE str) { char const *c_str = StringValueCStr(str); Real *vp = VpNewRbClass(0, c_str, klass, false, true); if (!vp) return Qnil; else return VpCheckGetValue(vp); }
.limit(digits)
Limit the number of significant digits in newly created BigDecimal
numbers to the specified value. Rounding is performed as necessary, as specified by .mode.
A limit of 0, the default, means no upper limit.
The limit specified by this method takes less priority over any limit specified to instance methods such as ceil, floor, truncate, or round.
# File 'ext/bigdecimal/bigdecimal.c', line 3775
static VALUE BigDecimal_limit(int argc, VALUE *argv, VALUE self) { VALUE nFig; VALUE nCur = SIZET2NUM(VpGetPrecLimit()); if (rb_scan_args(argc, argv, "01", &nFig) == 1) { int nf; if (NIL_P(nFig)) return nCur; nf = NUM2INT(nFig); if (nf < 0) { rb_raise(rb_eArgError, "argument must be positive"); } VpSetPrecLimit(nf); } return nCur; }
.mode(mode, setting = nil) ⇒ Integer
Returns an integer representing the mode settings for exception handling and rounding.
These modes control exception handling:
-
BigDecimal::EXCEPTION_NaN.
-
BigDecimal::EXCEPTION_INFINITY.
-
BigDecimal::EXCEPTION_UNDERFLOW.
-
BigDecimal::EXCEPTION_OVERFLOW.
-
BigDecimal::EXCEPTION_ZERODIVIDE.
-
BigDecimal::EXCEPTION_ALL.
Values for setting
for exception handling:
-
true
: sets the givenmode
totrue
. -
false
: sets the givenmode
tofalse
. -
nil
: does not modify the mode settings.
You can use method .save_exception_mode to temporarily change, and then automatically restore, exception modes.
For clarity, some examples below begin by setting all exception modes to false
.
This mode controls the way rounding is to be performed:
-
BigDecimal::ROUND_MODE
You can use method .save_rounding_mode to temporarily change, and then automatically restore, the rounding mode.
NaNs
Mode BigDecimal::EXCEPTION_NaN controls behavior when a BigDecimal NaN is created.
Settings:
-
false
(default): ReturnsBigDecimal('NaN')
. -
true
: Raises FloatDomainError.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
BigDecimal('NaN') # => NaN
BigDecimal.mode(BigDecimal::EXCEPTION_NaN, true) # => 2
BigDecimal('NaN') # Raises FloatDomainError
Infinities
Mode BigDecimal::EXCEPTION_INFINITY controls behavior when a BigDecimal Infinity or -Infinity is created. Settings:
-
false
(default): ReturnsBigDecimal('Infinity')
orBigDecimal('-Infinity')
. -
true
: Raises FloatDomainError.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
BigDecimal('Infinity') # => Infinity
BigDecimal('-Infinity') # => -Infinity
BigDecimal.mode(BigDecimal::EXCEPTION_INFINITY, true) # => 1
BigDecimal('Infinity') # Raises FloatDomainError
BigDecimal('-Infinity') # Raises FloatDomainError
Underflow
Mode BigDecimal::EXCEPTION_UNDERFLOW controls behavior when a BigDecimal underflow occurs. Settings:
-
false
(default): ReturnsBigDecimal('0')
orBigDecimal('-Infinity')
. -
true
: Raises FloatDomainError.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
def flow_under
x = BigDecimal('0.1')
100.times { x *= x }
end
flow_under # => 100
BigDecimal.mode(BigDecimal::EXCEPTION_UNDERFLOW, true) # => 4
flow_under # Raises FloatDomainError
Overflow
Mode BigDecimal::EXCEPTION_OVERFLOW controls behavior when a BigDecimal overflow occurs. Settings:
-
false
(default): ReturnsBigDecimal('Infinity')
orBigDecimal('-Infinity')
. -
true
: Raises FloatDomainError.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
def flow_over
x = BigDecimal('10')
100.times { x *= x }
end
flow_over # => 100
BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, true) # => 1
flow_over # Raises FloatDomainError
Zero Division
Mode BigDecimal::EXCEPTION_ZERODIVIDE controls behavior when a zero-division occurs. Settings:
-
false
(default): ReturnsBigDecimal('Infinity')
orBigDecimal('-Infinity')
. -
true
: Raises FloatDomainError.
Examples:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
one = BigDecimal('1')
zero = BigDecimal('0')
one / zero # => Infinity
BigDecimal.mode(BigDecimal::EXCEPTION_ZERODIVIDE, true) # => 16
one / zero # Raises FloatDomainError
All Exceptions
Mode BigDecimal::EXCEPTION_ALL controls all of the above:
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, true) # => 23
Rounding
Mode BigDecimal::ROUND_MODE controls the way rounding is to be performed; its setting
values are:
-
ROUND_UP: Round away from zero. Aliased as
:up
. -
ROUND_DOWN: Round toward zero. Aliased as
:down
and:truncate
. -
ROUND_HALF_UP: Round toward the nearest neighbor; if the neighbors are equidistant, round away from zero. Aliased as
:half_up
and:default
. -
ROUND_HALF_DOWN: Round toward the nearest neighbor; if the neighbors are equidistant, round toward zero. Aliased as
:half_down
. -
ROUND_HALF_EVEN (Banker’s rounding): Round toward the nearest neighbor; if the neighbors are equidistant, round toward the even neighbor. Aliased as
:half_even
and:banker
. -
ROUND_CEILING: Round toward positive infinity. Aliased as
:ceiling
and:ceil
. -
ROUND_FLOOR: Round toward negative infinity. Aliased as
:floor:
.
# File 'ext/bigdecimal/bigdecimal.c', line 1062
static VALUE BigDecimal_mode(int argc, VALUE *argv, VALUE self) { VALUE which; VALUE val; unsigned long f,fo; rb_scan_args(argc, argv, "11", &which, &val); f = (unsigned long)NUM2INT(which); if (f & VP_EXCEPTION_ALL) { /* Exception mode setting */ fo = VpGetException(); if (val == Qnil) return INT2FIX(fo); if (val != Qfalse && val!=Qtrue) { rb_raise(rb_eArgError, "second argument must be true or false"); return Qnil; /* Not reached */ } if (f & VP_EXCEPTION_INFINITY) { VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_INFINITY) : (fo & (~VP_EXCEPTION_INFINITY)))); } fo = VpGetException(); if (f & VP_EXCEPTION_NaN) { VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_NaN) : (fo & (~VP_EXCEPTION_NaN)))); } fo = VpGetException(); if (f & VP_EXCEPTION_UNDERFLOW) { VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_UNDERFLOW) : (fo & (~VP_EXCEPTION_UNDERFLOW)))); } fo = VpGetException(); if(f & VP_EXCEPTION_ZERODIVIDE) { VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_ZERODIVIDE) : (fo & (~VP_EXCEPTION_ZERODIVIDE)))); } fo = VpGetException(); return INT2FIX(fo); } if (VP_ROUND_MODE == f) { /* Rounding mode setting */ unsigned short sw; fo = VpGetRoundMode(); if (NIL_P(val)) return INT2FIX(fo); sw = check_rounding_mode(val); fo = VpSetRoundMode(sw); return INT2FIX(fo); } rb_raise(rb_eTypeError, "first argument for BigDecimal.mode invalid"); return Qnil; }
.save_exception_mode
Execute the provided block, but preserve the exception mode
BigDecimal.save_exception_mode do
BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
BigDecimal(BigDecimal('Infinity'))
BigDecimal(BigDecimal('-Infinity'))
BigDecimal(BigDecimal('NaN'))
end
For use with the BigDecimal::EXCEPTION_*
See .mode
# File 'ext/bigdecimal/bigdecimal.c', line 3836
static VALUE BigDecimal_save_exception_mode(VALUE self) { unsigned short const exception_mode = VpGetException(); int state; VALUE ret = rb_protect(rb_yield, Qnil, &state); VpSetException(exception_mode); if (state) rb_jump_tag(state); return ret; }
.save_limit
# File 'ext/bigdecimal/bigdecimal.c', line 3886
static VALUE BigDecimal_save_limit(VALUE self) { size_t const limit = VpGetPrecLimit(); int state; VALUE ret = rb_protect(rb_yield, Qnil, &state); VpSetPrecLimit(limit); if (state) rb_jump_tag(state); return ret; }
.save_rounding_mode
Execute the provided block, but preserve the rounding mode
BigDecimal.save_rounding_mode do
BigDecimal.mode(BigDecimal::ROUND_MODE, :up)
puts BigDecimal.mode(BigDecimal::ROUND_MODE)
end
For use with the BigDecimal::ROUND_*
See .mode
# File 'ext/bigdecimal/bigdecimal.c', line 3861
static VALUE BigDecimal_save_rounding_mode(VALUE self) { unsigned short const round_mode = VpGetRoundMode(); int state; VALUE ret = rb_protect(rb_yield, Qnil, &state); VpSetRoundMode(round_mode); if (state) rb_jump_tag(state); return ret; }
Instance Attribute Details
#finite? ⇒ Boolean
(readonly)
Returns True if the value is finite (not NaN or infinite).
# File 'ext/bigdecimal/bigdecimal.c', line 1226
static VALUE BigDecimal_IsFinite(VALUE self) { Real *p = GetVpValue(self, 1); if (VpIsNaN(p)) return Qfalse; if (VpIsInf(p)) return Qfalse; return Qtrue; }
#infinite? ⇒ Boolean
(readonly)
Returns nil, -1, or 1 depending on whether the value is finite, -Infinity, or Infinity.
# File 'ext/bigdecimal/bigdecimal.c', line 1216
static VALUE BigDecimal_IsInfinite(VALUE self) { Real *p = GetVpValue(self, 1); if (VpIsPosInf(p)) return INT2FIX(1); if (VpIsNegInf(p)) return INT2FIX(-1); return Qnil; }
#nan? ⇒ Boolean
(readonly)
Returns True if the value is Not a Number.
# File 'ext/bigdecimal/bigdecimal.c', line 1205
static VALUE BigDecimal_IsNaN(VALUE self) { Real *p = GetVpValue(self, 1); if (VpIsNaN(p)) return Qtrue; return Qfalse; }
#nonzero? ⇒ Boolean
(readonly)
Returns self if the value is non-zero, nil otherwise.
# File 'ext/bigdecimal/bigdecimal.c', line 1644
static VALUE BigDecimal_nonzero(VALUE self) { Real *a = GetVpValue(self, 1); return VpIsZero(a) ? Qnil : self; }
#zero? ⇒ Boolean
(readonly)
Returns True if the value is zero.
# File 'ext/bigdecimal/bigdecimal.c', line 1636
static VALUE BigDecimal_zero(VALUE self) { Real *a = GetVpValue(self, 1); return VpIsZero(a) ? Qtrue : Qfalse; }
Instance Method Details
#%
[ GitHub ]#*(r)
[ GitHub ]# File 'ext/bigdecimal/bigdecimal.c', line 1781
static VALUE BigDecimal_mult(VALUE self, VALUE r) { ENTER(5); Real *c, *a, *b; size_t mx; GUARD_OBJ(a, GetVpValue(self, 1)); if (RB_TYPE_P(r, T_FLOAT)) { b = GetVpValueWithPrec(r, 0, 1); } else if (RB_TYPE_P(r, T_RATIONAL)) { b = GetVpValueWithPrec(r, a->Prec*VpBaseFig(), 1); } else { b = GetVpValue(r,0); } if (!b) return DoSomeOne(self, r, '*'); SAVE(b); mx = a->Prec + b->Prec; GUARD_OBJ(c, NewZeroWrapLimited(1, mx * (VpBaseFig() + 1))); VpMult(c, a, b); return VpCheckGetValue(c); }
#**(other) ⇒ BigDecimal
# File 'ext/bigdecimal/bigdecimal.c', line 3229
static VALUE BigDecimal_power_op(VALUE self, VALUE exp) { return BigDecimal_power(1, &exp, self); }
#+(value) ⇒ BigDecimal
Returns the BigDecimal sum of self
and value
:
b = BigDecimal('111111.111') # => 0.111111111e6
b + 2 # => 0.111113111e6
b + 2.0 # => 0.111113111e6
b + Rational(2, 1) # => 0.111113111e6
b + Complex(2, 0) # => (0.111113111e6+0i)
See the [Note About Precision](BigDecimal.html#class-BigDecimal-label-A+Note+About+Precision).
# File 'ext/bigdecimal/bigdecimal.c', line 1445
static VALUE BigDecimal_add(VALUE self, VALUE r) { ENTER(5); Real *c, *a, *b; size_t mx; GUARD_OBJ(a, GetVpValue(self, 1)); if (RB_TYPE_P(r, T_FLOAT)) { b = GetVpValueWithPrec(r, 0, 1); } else if (RB_TYPE_P(r, T_RATIONAL)) { b = GetVpValueWithPrec(r, a->Prec*VpBaseFig(), 1); } else { b = GetVpValue(r, 0); } if (!b) return DoSomeOne(self,r,'+'); SAVE(b); if (VpIsNaN(b)) return b->obj; if (VpIsNaN(a)) return a->obj; mx = GetAddSubPrec(a, b); if (mx == (size_t)-1L) { GUARD_OBJ(c, NewZeroWrapLimited(1, VpBaseFig() + 1)); VpAddSub(c, a, b, 1); } else { GUARD_OBJ(c, NewZeroWrapLimited(1, mx * (VpBaseFig() + 1))); if (!mx) { VpSetInf(c, VpGetSign(a)); } else { VpAddSub(c, a, b, 1); } } return VpCheckGetValue(c); }
#+ ⇒ self
Returns self
:
+BigDecimal(5) # => 0.5e1
+BigDecimal(-5) # => -0.5e1
# File 'ext/bigdecimal/bigdecimal.c', line 1423
static VALUE BigDecimal_uplus(VALUE self) { return self; }
#-(value) ⇒ BigDecimal
Returns the BigDecimal difference of self
and value
:
b = BigDecimal('333333.333') # => 0.333333333e6
b - 2 # => 0.333331333e6
b - 2.0 # => 0.333331333e6
b - Rational(2, 1) # => 0.333331333e6
b - Complex(2, 0) # => (0.333331333e6+0i)
See the [Note About Precision](BigDecimal.html#class-BigDecimal-label-A+Note+About+Precision).
# File 'ext/bigdecimal/bigdecimal.c', line 1500
static VALUE BigDecimal_sub(VALUE self, VALUE r) { ENTER(5); Real *c, *a, *b; size_t mx; GUARD_OBJ(a, GetVpValue(self,1)); if (RB_TYPE_P(r, T_FLOAT)) { b = GetVpValueWithPrec(r, 0, 1); } else if (RB_TYPE_P(r, T_RATIONAL)) { b = GetVpValueWithPrec(r, a->Prec*VpBaseFig(), 1); } else { b = GetVpValue(r,0); } if (!b) return DoSomeOne(self,r,'-'); SAVE(b); if (VpIsNaN(b)) return b->obj; if (VpIsNaN(a)) return a->obj; mx = GetAddSubPrec(a,b); if (mx == (size_t)-1L) { GUARD_OBJ(c, NewZeroWrapLimited(1, VpBaseFig() + 1)); VpAddSub(c, a, b, -1); } else { GUARD_OBJ(c, NewZeroWrapLimited(1, mx *(VpBaseFig() + 1))); if (!mx) { VpSetInf(c,VpGetSign(a)); } else { VpAddSub(c, a, b, -1); } } return VpCheckGetValue(c); }
#- ⇒ BigDecimal
Returns the BigDecimal negation of self:
b0 = BigDecimal('1.5')
b1 = -b0 # => -0.15e1
b2 = -b1 # => 0.15e1
# File 'ext/bigdecimal/bigdecimal.c', line 1770
static VALUE BigDecimal_neg(VALUE self) { ENTER(5); Real *c, *a; GUARD_OBJ(a, GetVpValue(self, 1)); GUARD_OBJ(c, NewZeroWrapLimited(1, a->Prec *(VpBaseFig() + 1))); VpAsgn(c, a, -1); return VpCheckGetValue(c); }
#/
[ GitHub ]
#<(other) ⇒ Boolean
Returns true
if self
is less than other
, false
otherwise:
b = BigDecimal('1.5') # => 0.15e1
b < 2 # => true
b < 2.0 # => true
b < Rational(2, 1) # => true
b < 1.5 # => false
Raises an exception if the comparison cannot be made.
# File 'ext/bigdecimal/bigdecimal.c', line 1690
static VALUE BigDecimal_lt(VALUE self, VALUE r) { return BigDecimalCmp(self, r, '<'); }
#<=(other) ⇒ Boolean
Returns true
if self
is less or equal to than other
, false
otherwise:
b = BigDecimal('1.5') # => 0.15e1
b <= 2 # => true
b <= 2.0 # => true
b <= Rational(2, 1) # => true
b <= 1.5 # => true
b < 1 # => false
Raises an exception if the comparison cannot be made.
# File 'ext/bigdecimal/bigdecimal.c', line 1711
static VALUE BigDecimal_le(VALUE self, VALUE r) { return BigDecimalCmp(self, r, 'L'); }
#<=>(r)
The comparison operator. a <=> b is 0 if a == b, 1 if a > b, -1 if a < b.
# File 'ext/bigdecimal/bigdecimal.c', line 1654
static VALUE BigDecimal_comp(VALUE self, VALUE r) { return BigDecimalCmp(self, r, '*'); }
#==(r) Also known as: #===, #eql?
Tests for value equality; returns true if the values are equal.
The == and === operators and the eql? method have the same implementation for BigDecimal
.
Values may be coerced to perform the comparison:
BigDecimal('1.0') == 1.0 #=> true
# File 'ext/bigdecimal/bigdecimal.c', line 1670
static VALUE BigDecimal_eq(VALUE self, VALUE r) { return BigDecimalCmp(self, r, '='); }
#===(r)
Alias for #==.
#>(other) ⇒ Boolean
Returns true
if self
is greater than other
, false
otherwise:
b = BigDecimal('1.5')
b > 1 # => true
b > 1.0 # => true
b > Rational(1, 1) # => true
b > 2 # => false
Raises an exception if the comparison cannot be made.
# File 'ext/bigdecimal/bigdecimal.c', line 1731
static VALUE BigDecimal_gt(VALUE self, VALUE r) { return BigDecimalCmp(self, r, '>'); }
#>=(other) ⇒ Boolean
Returns true
if self
is greater than or equal to other
, false
otherwise:
b = BigDecimal('1.5')
b >= 1 # => true
b >= 1.0 # => true
b >= Rational(1, 1) # => true
b >= 1.5 # => true
b > 2 # => false
Raises an exception if the comparison cannot be made.
# File 'ext/bigdecimal/bigdecimal.c', line 1752
static VALUE BigDecimal_ge(VALUE self, VALUE r) { return BigDecimalCmp(self, r, 'G'); }
#_dump ⇒ String
Returns a string representing the marshalling of self
. See module Marshal.
inf = BigDecimal('Infinity') # => Infinity
dumped = inf._dump # => "9:Infinity"
BigDecimal._load(dumped) # => Infinity
# File 'ext/bigdecimal/bigdecimal.c', line 778
static VALUE BigDecimal_dump(int argc, VALUE *argv, VALUE self) { ENTER(5); Real *vp; char *psz; VALUE dummy; volatile VALUE dump; size_t len; rb_scan_args(argc, argv, "01", &dummy); GUARD_OBJ(vp,GetVpValue(self, 1)); dump = rb_str_new(0, VpNumOfChars(vp, "E")+50); psz = RSTRING_PTR(dump); snprintf(psz, RSTRING_LEN(dump), "%"PRIuSIZE":", VpMaxPrec(vp)*VpBaseFig()); len = strlen(psz); VpToString(vp, psz+len, RSTRING_LEN(dump)-len, 0, 0); rb_str_resize(dump, strlen(psz)); return dump; }
#abs ⇒ BigDecimal
Returns the BigDecimal absolute value of self
:
BigDecimal('5').abs # => 0.5e1
BigDecimal('-3').abs # => 0.3e1
# File 'ext/bigdecimal/bigdecimal.c', line 2382
static VALUE BigDecimal_abs(VALUE self) { ENTER(5); Real *c, *a; size_t mx; GUARD_OBJ(a, GetVpValue(self, 1)); mx = a->Prec *(VpBaseFig() + 1); GUARD_OBJ(c, NewZeroWrapLimited(1, mx)); VpAsgn(c, a, 1); VpChangeSign(c, 1); return VpCheckGetValue(c); }
#add(value, ndigits) ⇒ BigDecimal
Returns the BigDecimal sum of self
and value
with a precision of ndigits
decimal digits.
When ndigits
is less than the number of significant digits in the sum, the sum is rounded to that number of digits, according to the current rounding mode; see .mode.
Examples:
# Set the rounding mode.
BigDecimal.mode(BigDecimal::ROUND_MODE, :half_up)
b = BigDecimal('111111.111')
b.add(1, 0) # => 0.111112111e6
b.add(1, 3) # => 0.111e6
b.add(1, 6) # => 0.111112e6
b.add(1, 15) # => 0.111112111e6
b.add(1.0, 15) # => 0.111112111e6
b.add(Rational(1, 1), 15) # => 0.111112111e6
# File 'ext/bigdecimal/bigdecimal.c', line 2281
static VALUE BigDecimal_add2(VALUE self, VALUE b, VALUE n) { ENTER(2); Real *cv; SIGNED_VALUE mx = check_int_precision(n); if (mx == 0) return BigDecimal_add(self, b); else { size_t pl = VpSetPrecLimit(0); VALUE c = BigDecimal_add(self, b); VpSetPrecLimit(pl); GUARD_OBJ(cv, GetVpValue(c, 1)); VpLeftRound(cv, VpGetRoundMode(), mx); return VpCheckGetValue(cv); } }
#ceil(n)
Return the smallest integer greater than or equal to the value, as a BigDecimal
.
BigDecimal('3.14159').ceil #=> 4
BigDecimal('-9.1').ceil #=> -9
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.
BigDecimal('3.14159').ceil(3) #=> 3.142
BigDecimal('13345.234').ceil(-2) #=> 13400.0
# File 'ext/bigdecimal/bigdecimal.c', line 2641
static VALUE BigDecimal_ceil(int argc, VALUE *argv, VALUE self) { ENTER(5); Real *c, *a; int iLoc; VALUE vLoc; size_t mx, pl = VpSetPrecLimit(0); if (rb_scan_args(argc, argv, "01", &vLoc) == 0) { iLoc = 0; } else { iLoc = NUM2INT(vLoc); } GUARD_OBJ(a, GetVpValue(self, 1)); mx = a->Prec * (VpBaseFig() + 1); GUARD_OBJ(c, NewZeroWrapLimited(1, mx)); VpSetPrecLimit(pl); VpActiveRound(c, a, VP_ROUND_CEIL, iLoc); if (argc == 0) { return BigDecimal_to_i(VpCheckGetValue(c)); } return VpCheckGetValue(c); }
#clone
Alias for #dup.
#coerce(other)
The coerce method provides support for Ruby type coercion. It is not enabled by default.
This means that binary operations like + * / or - can often be performed on a BigDecimal
and an object of another type, if the other object can be coerced into a BigDecimal
value.
e.g.
a = BigDecimal("1.0")
b = a / 2.0 #=> 0.5
Note that coercing a ::String
to a BigDecimal
is not supported by default; it requires a special compile-time option when building Ruby.
# File 'ext/bigdecimal/bigdecimal.c', line 1387
static VALUE BigDecimal_coerce(VALUE self, VALUE other) { ENTER(2); VALUE obj; Real *b; if (RB_TYPE_P(other, T_FLOAT)) { GUARD_OBJ(b, GetVpValueWithPrec(other, 0, 1)); obj = rb_assoc_new(VpCheckGetValue(b), self); } else { if (RB_TYPE_P(other, T_RATIONAL)) { Real* pv = DATA_PTR(self); GUARD_OBJ(b, GetVpValueWithPrec(other, pv->Prec*VpBaseFig(), 1)); } else { GUARD_OBJ(b, GetVpValue(other, 1)); } obj = rb_assoc_new(b->obj, self); } return obj; }
Divide by the specified value.
- digits
-
If specified and less than the number of significant digits of the result, the result is rounded to that number of digits, according to BigDecimal.mode.
If digits is 0, the result is the same as for the / operator or #quo.
If digits is not specified, the result is an integer, by analogy with Float#div; see also BigDecimal#divmod.
Examples:
a = BigDecimal("4")
b = BigDecimal("3")
a.div(b, 3) # => 0.133e1
a.div(b, 0) # => 0.1333333333333333333e1
a / b # => 0.1333333333333333333e1
a.quo(b) # => 0.1333333333333333333e1
a.div(b) # => 1
# File 'ext/bigdecimal/bigdecimal.c', line 2246
static VALUE BigDecimal_div3(int argc, VALUE *argv, VALUE self) { VALUE b,n; rb_scan_args(argc, argv, "11", &b, &n); return BigDecimal_div2(self, b, n); }
#divmod(value)
Divides by the specified value, and returns the quotient and modulus as BigDecimal
numbers. The quotient is rounded towards negative infinity.
For example:
require 'bigdecimal'
a = BigDecimal("42")
b = BigDecimal("9")
q, m = a.divmod(b)
c = q * b + m
a == c #=> true
The quotient q is (a/b).floor, and the modulus is the amount that must be added to q * b to get a.
# File 'ext/bigdecimal/bigdecimal.c', line 2148
static VALUE BigDecimal_divmod(VALUE self, VALUE r) { ENTER(5); Real *div = NULL, *mod = NULL; if (BigDecimal_DoDivmod(self, r, &div, &mod)) { SAVE(div); SAVE(mod); return rb_assoc_new(VpCheckGetValue(div), VpCheckGetValue(mod)); } return DoSomeOne(self,r,rb_intern("divmod")); }
#dup Also known as: #clone
[ GitHub ]# File 'ext/bigdecimal/bigdecimal.c', line 3251
static VALUE BigDecimal_clone(VALUE self) { return self; }
#eql?(r)
Alias for #==.
#exponent
Returns the exponent of the BigDecimal
number, as an ::Integer
.
If the number can be represented as 0.xxxxxx*10**n where xxxxxx is a string of digits with no leading zeros, then n is the exponent.
# File 'ext/bigdecimal/bigdecimal.c', line 2832
static VALUE BigDecimal_exponent(VALUE self) { ssize_t e = VpExponent10(GetVpValue(self, 1)); return SSIZET2NUM(e); }
#fix
Return the integer part of the number, as a BigDecimal
.
# File 'ext/bigdecimal/bigdecimal.c', line 2424
static VALUE BigDecimal_fix(VALUE self) { ENTER(5); Real *c, *a; size_t mx; GUARD_OBJ(a, GetVpValue(self, 1)); mx = a->Prec *(VpBaseFig() + 1); GUARD_OBJ(c, NewZeroWrapLimited(1, mx)); VpActiveRound(c, a, VP_ROUND_DOWN, 0); /* 0: round off */ return VpCheckGetValue(c); }
#floor(n)
Return the largest integer less than or equal to the value, as a BigDecimal
.
BigDecimal('3.14159').floor #=> 3
BigDecimal('-9.1').floor #=> -10
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.
BigDecimal('3.14159').floor(3) #=> 3.141
BigDecimal('13345.234').floor(-2) #=> 13300.0
# File 'ext/bigdecimal/bigdecimal.c', line 2594
static VALUE BigDecimal_floor(int argc, VALUE *argv, VALUE self) { ENTER(5); Real *c, *a; int iLoc; VALUE vLoc; size_t mx, pl = VpSetPrecLimit(0); if (rb_scan_args(argc, argv, "01", &vLoc)==0) { iLoc = 0; } else { iLoc = NUM2INT(vLoc); } GUARD_OBJ(a, GetVpValue(self, 1)); mx = a->Prec * (VpBaseFig() + 1); GUARD_OBJ(c, NewZeroWrapLimited(1, mx)); VpSetPrecLimit(pl); VpActiveRound(c, a, VP_ROUND_FLOOR, iLoc); #ifdef BIGDECIMAL_DEBUG VPrint(stderr, "floor: c=%\n", c); #endif if (argc == 0) { return BigDecimal_to_i(VpCheckGetValue(c)); } return VpCheckGetValue(c); }
#frac
Return the fractional part of the number, as a BigDecimal
.
# File 'ext/bigdecimal/bigdecimal.c', line 2563
static VALUE BigDecimal_frac(VALUE self) { ENTER(5); Real *c, *a; size_t mx; GUARD_OBJ(a, GetVpValue(self, 1)); mx = a->Prec * (VpBaseFig() + 1); GUARD_OBJ(c, NewZeroWrapLimited(1, mx)); VpFrac(c, a); return VpCheckGetValue(c); }
#hash ⇒ Integer
Returns the integer hash value for self
.
Two instances of BigDecimal have the same hash value if and only if they have equal:
-
Sign.
-
Fractional part.
-
Exponent.
# File 'ext/bigdecimal/bigdecimal.c', line 749
static VALUE BigDecimal_hash(VALUE self) { ENTER(1); Real *p; st_index_t hash; GUARD_OBJ(p, GetVpValue(self, 1)); hash = (st_index_t)p->sign; /* hash!=2: the case for 0(1),NaN(0) or +-Infinity(3) is sign itself */ if(hash == 2 || hash == (st_index_t)-2) { hash ^= rb_memhash(p->frac, sizeof(DECDIG)*p->Prec); hash += p->exponent; } return ST2FIX(hash); }
#inspect
Returns a string representation of self.
BigDecimal("1234.5678").inspect
#=> "0.12345678e4"
# File 'ext/bigdecimal/bigdecimal.c', line 2844
static VALUE BigDecimal_inspect(VALUE self) { ENTER(5); Real *vp; volatile VALUE str; size_t nc; GUARD_OBJ(vp, GetVpValue(self, 1)); nc = VpNumOfChars(vp, "E"); str = rb_str_new(0, nc); VpToString(vp, RSTRING_PTR(str), RSTRING_LEN(str), 0, 0); rb_str_resize(str, strlen(RSTRING_PTR(str))); return str; }
#modulo
[ GitHub ]
#mult(other, ndigits) ⇒ BigDecimal
Returns the BigDecimal product of self
and value
with a precision of ndigits
decimal digits.
When ndigits
is less than the number of significant digits in the sum, the sum is rounded to that number of digits, according to the current rounding mode; see .mode.
Examples:
# Set the rounding mode.
BigDecimal.mode(BigDecimal::ROUND_MODE, :half_up)
b = BigDecimal('555555.555')
b.mult(3, 0) # => 0.1666666665e7
b.mult(3, 3) # => 0.167e7
b.mult(3, 6) # => 0.166667e7
b.mult(3, 15) # => 0.1666666665e7
b.mult(3.0, 0) # => 0.1666666665e7
b.mult(Rational(3, 1), 0) # => 0.1666666665e7
b.mult(Complex(3, 0), 0) # => (0.1666666665e7+0.0i)
# File 'ext/bigdecimal/bigdecimal.c', line 2354
static VALUE BigDecimal_mult2(VALUE self, VALUE b, VALUE n) { ENTER(2); Real *cv; SIGNED_VALUE mx = check_int_precision(n); if (mx == 0) return BigDecimal_mult(self, b); else { size_t pl = VpSetPrecLimit(0); VALUE c = BigDecimal_mult(self, b); VpSetPrecLimit(pl); GUARD_OBJ(cv, GetVpValue(c, 1)); VpLeftRound(cv, VpGetRoundMode(), mx); return VpCheckGetValue(cv); } }
#n_significant_digits ⇒ Integer
Returns the number of decimal significant digits in self
.
BigDecimal("0").n_significant_digits # => 0
BigDecimal("1").n_significant_digits # => 1
BigDecimal("1.1").n_significant_digits # => 2
BigDecimal("3.1415").n_significant_digits # => 5
BigDecimal("-1e20").n_significant_digits # => 1
BigDecimal("1e-20").n_significant_digits # => 1
BigDecimal("Infinity").n_significant_digits # => 0
BigDecimal("-Infinity").n_significant_digits # => 0
BigDecimal("NaN").n_significant_digits # => 0
# File 'ext/bigdecimal/bigdecimal.c', line 709
static VALUE BigDecimal_n_significant_digits(VALUE self) { ENTER(1); Real *p; GUARD_OBJ(p, GetVpValue(self, 1)); if (VpIsZero(p) || !VpIsDef(p)) { return INT2FIX(0); } ssize_t n = p->Prec; /* The length of frac without trailing zeros. */ for (n = p->Prec; n > 0 && p->frac[n-1] == 0; --n); if (n == 0) return INT2FIX(0); DECDIG x; int nlz = BASE_FIG; for (x = p->frac[0]; x > 0; x /= 10) --nlz; int ntz = 0; for (x = p->frac[n-1]; x > 0 && x % 10 == 0; x /= 10) ++ntz; ssize_t n_significant_digits = BASE_FIG*n - nlz - ntz; return SSIZET2NUM(n_significant_digits); }
#power(n)
#power(n, prec)
Returns the value raised to the power of n.
Note that n must be an ::Integer
.
Also available as the operator **.
# File 'ext/bigdecimal/bigdecimal.c', line 2987
static VALUE BigDecimal_power(int argc, VALUE*argv, VALUE self) { ENTER(5); VALUE vexp, prec; Real* exp = NULL; Real *x, *y; ssize_t mp, ma, n; SIGNED_VALUE int_exp; double d; rb_scan_args(argc, argv, "11", &vexp, &prec); GUARD_OBJ(x, GetVpValue(self, 1)); n = NIL_P(prec) ? (ssize_t)(x->Prec*VpBaseFig()) : NUM2SSIZET(prec); if (VpIsNaN(x)) { y = NewZeroWrapLimited(1, n); VpSetNaN(y); RB_GC_GUARD(y->obj); return VpCheckGetValue(y); } retry: switch (TYPE(vexp)) { case T_FIXNUM: break; case T_BIGNUM: break; case T_FLOAT: d = RFLOAT_VALUE(vexp); if (d == round(d)) { if (FIXABLE(d)) { vexp = LONG2FIX((long)d); } else { vexp = rb_dbl2big(d); } goto retry; } if (NIL_P(prec)) { n += BIGDECIMAL_DOUBLE_FIGURES; } exp = GetVpValueWithPrec(vexp, 0, 1); break; case T_RATIONAL: if (is_zero(rb_rational_num(vexp))) { if (is_positive(vexp)) { vexp = INT2FIX(0); goto retry; } } else if (is_one(rb_rational_den(vexp))) { vexp = rb_rational_num(vexp); goto retry; } exp = GetVpValueWithPrec(vexp, n, 1); if (NIL_P(prec)) { n += n; } break; case T_DATA: if (is_kind_of_BigDecimal(vexp)) { VALUE zero = INT2FIX(0); VALUE rounded = BigDecimal_round(1, &zero, vexp); if (RTEST(BigDecimal_eq(vexp, rounded))) { vexp = BigDecimal_to_i(vexp); goto retry; } if (NIL_P(prec)) { GUARD_OBJ(y, GetVpValue(vexp, 1)); n += y->Prec*VpBaseFig(); } exp = DATA_PTR(vexp); break; } /* fall through */ default: rb_raise(rb_eTypeError, "wrong argument type %"PRIsVALUE" (expected scalar Numeric)", RB_OBJ_CLASSNAME(vexp)); } if (VpIsZero(x)) { if (is_negative(vexp)) { y = NewZeroWrapNolimit(1, n); if (BIGDECIMAL_NEGATIVE_P(x)) { if (is_integer(vexp)) { if (is_even(vexp)) { /* (-0) ** (-even_integer) -> Infinity */ VpSetPosInf(y); } else { /* (-0) ** (-odd_integer) -> -Infinity */ VpSetNegInf(y); } } else { /* (-0) ** (-non_integer) -> Infinity */ VpSetPosInf(y); } } else { /* (+0) ** (-num) -> Infinity */ VpSetPosInf(y); } RB_GC_GUARD(y->obj); return VpCheckGetValue(y); } else if (is_zero(vexp)) { return VpCheckGetValue(NewOneWrapLimited(1, n)); } else { return VpCheckGetValue(NewZeroWrapLimited(1, n)); } } if (is_zero(vexp)) { return VpCheckGetValue(NewOneWrapLimited(1, n)); } else if (is_one(vexp)) { return self; } if (VpIsInf(x)) { if (is_negative(vexp)) { if (BIGDECIMAL_NEGATIVE_P(x)) { if (is_integer(vexp)) { if (is_even(vexp)) { /* (-Infinity) ** (-even_integer) -> +0 */ return VpCheckGetValue(NewZeroWrapLimited(1, n)); } else { /* (-Infinity) ** (-odd_integer) -> -0 */ return VpCheckGetValue(NewZeroWrapLimited(-1, n)); } } else { /* (-Infinity) ** (-non_integer) -> -0 */ return VpCheckGetValue(NewZeroWrapLimited(-1, n)); } } else { return VpCheckGetValue(NewZeroWrapLimited(1, n)); } } else { y = NewZeroWrapLimited(1, n); if (BIGDECIMAL_NEGATIVE_P(x)) { if (is_integer(vexp)) { if (is_even(vexp)) { VpSetPosInf(y); } else { VpSetNegInf(y); } } else { /* TODO: support complex */ rb_raise(rb_eMathDomainError, "a non-integral exponent for a negative base"); } } else { VpSetPosInf(y); } return VpCheckGetValue(y); } } if (exp != NULL) { return bigdecimal_power_by_bigdecimal(x, exp, n); } else if (RB_TYPE_P(vexp, T_BIGNUM)) { VALUE abs_value = BigDecimal_abs(self); if (is_one(abs_value)) { return VpCheckGetValue(NewOneWrapLimited(1, n)); } else if (RTEST(rb_funcall(abs_value, '<', 1, INT2FIX(1)))) { if (is_negative(vexp)) { y = NewZeroWrapLimited(1, n); VpSetInf(y, (is_even(vexp) ? 1 : -1) * VpGetSign(x)); return VpCheckGetValue(y); } else if (BIGDECIMAL_NEGATIVE_P(x) && is_even(vexp)) { return VpCheckGetValue(NewZeroWrapLimited(-1, n)); } else { return VpCheckGetValue(NewZeroWrapLimited(1, n)); } } else { if (is_positive(vexp)) { y = NewZeroWrapLimited(1, n); VpSetInf(y, (is_even(vexp) ? 1 : -1) * VpGetSign(x)); return VpCheckGetValue(y); } else if (BIGDECIMAL_NEGATIVE_P(x) && is_even(vexp)) { return VpCheckGetValue(NewZeroWrapLimited(-1, n)); } else { return VpCheckGetValue(NewZeroWrapLimited(1, n)); } } } int_exp = FIX2LONG(vexp); ma = int_exp; if (ma < 0) ma = -ma; if (ma == 0) ma = 1; if (VpIsDef(x)) { mp = x->Prec * (VpBaseFig() + 1); GUARD_OBJ(y, NewZeroWrapLimited(1, mp * (ma + 1))); } else { GUARD_OBJ(y, NewZeroWrapLimited(1, 1)); } VpPowerByInt(y, x, int_exp); if (!NIL_P(prec) && VpIsDef(y)) { VpMidRound(y, VpGetRoundMode(), n); } return VpCheckGetValue(y); }
#precision ⇒ Integer
Returns the number of decimal digits in self
:
BigDecimal("0").precision # => 0
BigDecimal("1").precision # => 1
BigDecimal("1.1").precision # => 2
BigDecimal("3.1415").precision # => 5
BigDecimal("-1e20").precision # => 21
BigDecimal("1e-20").precision # => 20
BigDecimal("Infinity").precision # => 0
BigDecimal("-Infinity").precision # => 0
BigDecimal("NaN").precision # => 0
# File 'ext/bigdecimal/bigdecimal.c', line 643
static VALUE BigDecimal_precision(VALUE self) { ssize_t precision; BigDecimal_count_precision_and_scale(self, &precision, NULL); return SSIZET2NUM(precision); }
#precision_scale ⇒ Array
, Integer
Returns a 2-length array; the first item is the result of #precision and the second one is of #scale.
See #precision. See #scale.
# File 'ext/bigdecimal/bigdecimal.c', line 685
static VALUE BigDecimal_precision_scale(VALUE self) { ssize_t precision, scale; BigDecimal_count_precision_and_scale(self, &precision, &scale); return rb_assoc_new(SSIZET2NUM(precision), SSIZET2NUM(scale)); }
#precs ⇒ Array
Returns an Array of two ::Integer
values that represent platform-dependent internal storage properties.
This method is deprecated and will be removed in the future. Instead, use #n_significant_digits for obtaining the number of significant digits in scientific notation, and #precision for obtaining the number of digits in decimal notation.
# File 'ext/bigdecimal/bigdecimal.c', line 496
static VALUE BigDecimal_prec(VALUE self) { ENTER(1); Real *p; VALUE obj; rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "BigDecimal#precs is deprecated and will be removed in the future; " "use BigDecimal#precision instead."); GUARD_OBJ(p, GetVpValue(self, 1)); obj = rb_assoc_new(SIZET2NUM(p->Prec*VpBaseFig()), SIZET2NUM(p->MaxPrec*VpBaseFig())); return obj; }
#quo(value) ⇒ BigDecimal
#quo(value, digits) ⇒ BigDecimal
BigDecimal
#quo(value, digits) ⇒ BigDecimal
Divide by the specified value.
- digits
-
If specified and less than the number of significant digits of the result, the result is rounded to the given number of digits, according to the rounding mode indicated by BigDecimal.mode.
If digits is 0 or omitted, the result is the same as for the / operator.
# File 'ext/bigdecimal/bigdecimal.c', line 1908
static VALUE BigDecimal_quo(int argc, VALUE *argv, VALUE self) { VALUE value, digits, result; SIGNED_VALUE n = -1; argc = rb_scan_args(argc, argv, "11", &value, &digits); if (argc > 1) { n = check_int_precision(digits); } if (n > 0) { result = BigDecimal_div2(self, value, digits); } else { result = BigDecimal_div(self, value); } return result; }
#remainder
[ GitHub ]#round(n, mode)
Round to the nearest integer (by default), returning the result as a BigDecimal
if n is specified, or as an ::Integer
if it isn’t.
BigDecimal('3.14159').round #=> 3
BigDecimal('8.7').round #=> 9
BigDecimal('-9.9').round #=> -10
BigDecimal('3.14159').round(2).class.name #=> "BigDecimal"
BigDecimal('3.14159').round.class.name #=> "Integer"
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result, and return value will be an ::Integer
.
BigDecimal('3.14159').round(3) #=> 3.142
BigDecimal('13345.234').round(-2) #=> 13300
The value of the optional mode argument can be used to determine how rounding is performed; see .mode.
# File 'ext/bigdecimal/bigdecimal.c', line 2463
static VALUE BigDecimal_round(int argc, VALUE *argv, VALUE self) { ENTER(5); Real *c, *a; int iLoc = 0; VALUE vLoc; VALUE vRound; int round_to_int = 0; size_t mx, pl; unsigned short sw = VpGetRoundMode(); switch (rb_scan_args(argc, argv, "02", &vLoc, &vRound)) { case 0: iLoc = 0; round_to_int = 1; break; case 1: if (RB_TYPE_P(vLoc, T_HASH)) { sw = check_rounding_mode_option(vLoc); } else { iLoc = NUM2INT(vLoc); if (iLoc < 1) round_to_int = 1; } break; case 2: iLoc = NUM2INT(vLoc); if (RB_TYPE_P(vRound, T_HASH)) { sw = check_rounding_mode_option(vRound); } else { sw = check_rounding_mode(vRound); } break; default: break; } pl = VpSetPrecLimit(0); GUARD_OBJ(a, GetVpValue(self, 1)); mx = a->Prec * (VpBaseFig() + 1); GUARD_OBJ(c, NewZeroWrapLimited(1, mx)); VpSetPrecLimit(pl); VpActiveRound(c, a, sw, iLoc); if (round_to_int) { return BigDecimal_to_i(VpCheckGetValue(c)); } return VpCheckGetValue(c); }
#scale ⇒ Integer
Returns the number of decimal digits following the decimal digits in self
.
BigDecimal("0").scale # => 0
BigDecimal("1").scale # => 1
BigDecimal("1.1").scale # => 1
BigDecimal("3.1415").scale # => 4
BigDecimal("-1e20").precision # => 0
BigDecimal("1e-20").precision # => 20
BigDecimal("Infinity").scale # => 0
BigDecimal("-Infinity").scale # => 0
BigDecimal("NaN").scale # => 0
# File 'ext/bigdecimal/bigdecimal.c', line 667
static VALUE BigDecimal_scale(VALUE self) { ssize_t scale; BigDecimal_count_precision_and_scale(self, NULL, &scale); return SSIZET2NUM(scale); }
#sign
Returns the sign of the value.
Returns a positive value if > 0, a negative value if < 0. It behaves the same with zeros - it returns a positive value for a positive zero (BigDecimal(‘0’)) and a negative value for a negative zero (BigDecimal(‘-0’)).
The specific value returned indicates the type and sign of the BigDecimal
, as follows:
- BigDecimal::SIGN_NaN
-
value is Not a Number
- BigDecimal::SIGN_POSITIVE_ZERO
-
value is +0
- BigDecimal::SIGN_NEGATIVE_ZERO
-
value is -0
- BigDecimal::SIGN_POSITIVE_INFINITE
-
value is +Infinity
- BigDecimal::SIGN_NEGATIVE_INFINITE
-
value is -Infinity
- BigDecimal::SIGN_POSITIVE_FINITE
-
value is positive
- BigDecimal::SIGN_NEGATIVE_FINITE
-
value is negative
# File 'ext/bigdecimal/bigdecimal.c', line 3811
static VALUE BigDecimal_sign(VALUE self) { /* sign */ int s = GetVpValue(self, 1)->sign; return INT2FIX(s); }
#split
Splits a BigDecimal
number into four parts, returned as an array of values.
The first value represents the sign of the BigDecimal
, and is -1 or 1, or 0 if the BigDecimal
is Not a Number.
The second value is a string representing the significant digits of the BigDecimal
, with no leading zeros.
The third value is the base used for arithmetic (currently always 10) as an ::Integer
.
The fourth value is an ::Integer
exponent.
If the BigDecimal
can be represented as 0.xxxxxx*10**n, then xxxxxx is the string of significant digits with no leading zeros, and n is the exponent.
From these values, you can translate a BigDecimal
to a float as follows:
sign, significant_digits, base, exponent = a.split
f = sign * "0.#{significant_digits}".to_f * (base ** exponent)
(Note that the to_f method is provided as a more convenient way to translate a BigDecimal
to a ::Float
.)
# File 'ext/bigdecimal/bigdecimal.c', line 2795
static VALUE BigDecimal_split(VALUE self) { ENTER(5); Real *vp; VALUE obj,str; ssize_t e, s; char *psz1; GUARD_OBJ(vp, GetVpValue(self, 1)); str = rb_str_new(0, VpNumOfChars(vp, "E")); psz1 = RSTRING_PTR(str); VpSzMantissa(vp, psz1, RSTRING_LEN(str)); s = 1; if(psz1[0] == '-') { size_t len = strlen(psz1 + 1); memmove(psz1, psz1 + 1, len); psz1[len] = '\0'; s = -1; } if (psz1[0] == 'N') s = 0; /* NaN */ e = VpExponent10(vp); obj = rb_ary_new2(4); rb_ary_push(obj, INT2FIX(s)); rb_ary_push(obj, str); rb_str_resize(str, strlen(psz1)); rb_ary_push(obj, INT2FIX(10)); rb_ary_push(obj, SSIZET2NUM(e)); return obj; }
#sqrt(n)
Returns the square root of the value.
Result has at least n significant digits.
# File 'ext/bigdecimal/bigdecimal.c', line 2404
static VALUE BigDecimal_sqrt(VALUE self, VALUE nFig) { ENTER(5); Real *c, *a; size_t mx, n; GUARD_OBJ(a, GetVpValue(self, 1)); mx = a->Prec * (VpBaseFig() + 1); n = check_int_precision(nFig); n += VpDblFig() + VpBaseFig(); if (mx <= n) mx = n; GUARD_OBJ(c, NewZeroWrapLimited(1, mx)); VpSqrt(c, a); return VpCheckGetValue(c); }
#sub(value, digits) ⇒ BigDecimal
Subtract the specified value.
e.g.
c = a.sub(b,n)
- digits
-
If specified and less than the number of significant digits of the result, the result is rounded to that number of digits, according to BigDecimal.mode.
# File 'ext/bigdecimal/bigdecimal.c', line 2311
static VALUE BigDecimal_sub2(VALUE self, VALUE b, VALUE n) { ENTER(2); Real *cv; SIGNED_VALUE mx = check_int_precision(n); if (mx == 0) return BigDecimal_sub(self, b); else { size_t pl = VpSetPrecLimit(0); VALUE c = BigDecimal_sub(self, b); VpSetPrecLimit(pl); GUARD_OBJ(cv, GetVpValue(c, 1)); VpLeftRound(cv, VpGetRoundMode(), mx); return VpCheckGetValue(cv); } }
#to_d ⇒ BigDecimal
Returns self.
require 'bigdecimal/util'
d = BigDecimal("3.14")
d.to_d # => 0.314e1
# File 'ext/bigdecimal/lib/bigdecimal/util.rb', line 110
def to_d self end
#to_digits ⇒ String
#to_f
# File 'ext/bigdecimal/bigdecimal.c', line 1294
static VALUE BigDecimal_to_f(VALUE self) { ENTER(1); Real *p; double d; SIGNED_VALUE e; char *buf; volatile VALUE str; GUARD_OBJ(p, GetVpValue(self, 1)); if (VpVtoD(&d, &e, p) != 1) return rb_float_new(d); if (e > (SIGNED_VALUE)(DBL_MAX_10_EXP+BASE_FIG)) goto overflow; if (e < (SIGNED_VALUE)(DBL_MIN_10_EXP-BASE_FIG)) goto underflow; str = rb_str_new(0, VpNumOfChars(p, "E")); buf = RSTRING_PTR(str); VpToString(p, buf, RSTRING_LEN(str), 0, 0); errno = 0; d = strtod(buf, 0); if (errno == ERANGE) { if (d == 0.0) goto underflow; if (fabs(d) >= HUGE_VAL) goto overflow; } return rb_float_new(d); overflow: VpException(VP_EXCEPTION_OVERFLOW, "BigDecimal to Float conversion", 0); if (BIGDECIMAL_NEGATIVE_P(p)) return rb_float_new(VpGetDoubleNegInf()); else return rb_float_new(VpGetDoublePosInf()); underflow: VpException(VP_EXCEPTION_UNDERFLOW, "BigDecimal to Float conversion", 0); if (BIGDECIMAL_NEGATIVE_P(p)) return rb_float_new(-0.0); else return rb_float_new(0.0); }
#to_i Also known as: #to_int
Returns the value as an ::Integer
.
If the BigDecimal
is infinity or NaN, raises FloatDomainError.
# File 'ext/bigdecimal/bigdecimal.c', line 1247
static VALUE BigDecimal_to_i(VALUE self) { ENTER(5); ssize_t e, nf; Real *p; GUARD_OBJ(p, GetVpValue(self, 1)); BigDecimal_check_num(p); e = VpExponent10(p); if (e <= 0) return INT2FIX(0); nf = VpBaseFig(); if (e <= nf) { return LONG2NUM((long)(VpGetSign(p) * (DECDIG_DBL_SIGNED)p->frac[0])); } else { VALUE a = BigDecimal_split(self); VALUE digits = RARRAY_AREF(a, 1); VALUE numerator = rb_funcall(digits, rb_intern("to_i"), 0); VALUE ret; ssize_t dpower = e - (ssize_t)RSTRING_LEN(digits); if (BIGDECIMAL_NEGATIVE_P(p)) { numerator = rb_funcall(numerator, '*', 1, INT2FIX(-1)); } if (dpower < 0) { ret = rb_funcall(numerator, rb_intern("div"), 1, rb_funcall(INT2FIX(10), rb_intern("**"), 1, INT2FIX(-dpower))); } else { ret = rb_funcall(numerator, '*', 1, rb_funcall(INT2FIX(10), rb_intern("**"), 1, INT2FIX(dpower))); } if (RB_TYPE_P(ret, T_FLOAT)) { rb_raise(rb_eFloatDomainError, "Infinity"); } return ret; } }
#to_int
Alias for #to_i.
#to_r
Converts a BigDecimal
to a ::Rational
.
# File 'ext/bigdecimal/bigdecimal.c', line 1341
static VALUE BigDecimal_to_r(VALUE self) { Real *p; ssize_t sign, power, denomi_power; VALUE a, digits, numerator; p = GetVpValue(self, 1); BigDecimal_check_num(p); sign = VpGetSign(p); power = VpExponent10(p); a = BigDecimal_split(self); digits = RARRAY_AREF(a, 1); denomi_power = power - RSTRING_LEN(digits); numerator = rb_funcall(digits, rb_intern("to_i"), 0); if (sign < 0) { numerator = rb_funcall(numerator, '*', 1, INT2FIX(-1)); } if (denomi_power < 0) { return rb_Rational(numerator, rb_funcall(INT2FIX(10), rb_intern("**"), 1, INT2FIX(-denomi_power))); } else { return rb_Rational1(rb_funcall(numerator, '*', 1, rb_funcall(INT2FIX(10), rb_intern("**"), 1, INT2FIX(denomi_power)))); } }
#to_s(s) ⇒ ?
Converts the value to a string.
The default format looks like 0.xxxxEnn.
The optional parameter s consists of either an integer; or an optional ‘+’ or ‘ ’, followed by an optional number, followed by an optional ‘E’ or ‘F’.
If there is a ‘+’ at the start of s, positive values are returned with a leading ‘+’.
A space at the start of s returns positive values with a leading space.
If s contains a number, a space is inserted after each group of that many fractional digits.
If s ends with an ‘E’, engineering notation (0.xxxxEnn) is used.
If s ends with an ‘F’, conventional floating point notation is used.
Examples:
BigDecimal('-123.45678901234567890').to_s('5F')
#=> '-123.45678 90123 45678 9'
BigDecimal('123.45678901234567890').to_s('+8F')
#=> '+123.45678901 23456789'
BigDecimal('123.45678901234567890').to_s(' F')
#=> ' 123.4567890123456789'
# File 'ext/bigdecimal/bigdecimal.c', line 2700
static VALUE BigDecimal_to_s(int argc, VALUE *argv, VALUE self) { ENTER(5); int fmt = 0; /* 0: E format, 1: F format */ int fPlus = 0; /* 0: default, 1: set ' ' before digits, 2: set '+' before digits. */ Real *vp; volatile VALUE str; char *psz; char ch; size_t nc, mc = 0; SIGNED_VALUE m; VALUE f; GUARD_OBJ(vp, GetVpValue(self, 1)); if (rb_scan_args(argc, argv, "01", &f) == 1) { if (RB_TYPE_P(f, T_STRING)) { psz = StringValueCStr(f); if (*psz == ' ') { fPlus = 1; psz++; } else if (*psz == '+') { fPlus = 2; psz++; } while ((ch = *psz++) != 0) { if (ISSPACE(ch)) { continue; } if (!ISDIGIT(ch)) { if (ch == 'F' || ch == 'f') { fmt = 1; /* F format */ } break; } mc = mc*10 + ch - '0'; } } else { m = NUM2INT(f); if (m <= 0) { rb_raise(rb_eArgError, "argument must be positive"); } mc = (size_t)m; } } if (fmt) { nc = VpNumOfChars(vp, "F"); } else { nc = VpNumOfChars(vp, "E"); } if (mc > 0) { nc += (nc + mc - 1) / mc + 1; } str = rb_usascii_str_new(0, nc); psz = RSTRING_PTR(str); if (fmt) { VpToFString(vp, psz, RSTRING_LEN(str), mc, fPlus); } else { VpToString (vp, psz, RSTRING_LEN(str), mc, fPlus); } rb_str_resize(str, strlen(psz)); return str; }
#truncate(n)
Truncate to the nearest integer (by default), returning the result as a BigDecimal
.
BigDecimal('3.14159').truncate #=> 3
BigDecimal('8.7').truncate #=> 8
BigDecimal('-9.9').truncate #=> -9
If n is specified and positive, the fractional part of the result has no more than that many digits.
If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.
BigDecimal('3.14159').truncate(3) #=> 3.141
BigDecimal('13345.234').truncate(-2) #=> 13300.0
# File 'ext/bigdecimal/bigdecimal.c', line 2534
static VALUE BigDecimal_truncate(int argc, VALUE *argv, VALUE self) { ENTER(5); Real *c, *a; int iLoc; VALUE vLoc; size_t mx, pl = VpSetPrecLimit(0); if (rb_scan_args(argc, argv, "01", &vLoc) == 0) { iLoc = 0; } else { iLoc = NUM2INT(vLoc); } GUARD_OBJ(a, GetVpValue(self, 1)); mx = a->Prec * (VpBaseFig() + 1); GUARD_OBJ(c, NewZeroWrapLimited(1, mx)); VpSetPrecLimit(pl); VpActiveRound(c, a, VP_ROUND_DOWN, iLoc); /* 0: truncate */ if (argc == 0) { return BigDecimal_to_i(VpCheckGetValue(c)); } return VpCheckGetValue(c); }