Class: Float
Overview
******************************************************************
Float objects represent inexact real numbers using the native
architecture's double-precision floating point representation.
Floating point has a different arithmetic and is an inexact number.
So you should know its esoteric system. see following:
- http://docs.sun.com/source/806-3568/ncg_goldberg.html
- http://wiki.github.com/rdp/ruby_tutorials_core/ruby-talk-faq#wiki-floats_imprecise
- http://en.wikipedia.org/wiki/Floating_point#Accuracy_problems
Constant Summary collapse
- ROUNDS =
-1:: Indeterminable 0:: Rounding towards zero 1:: Rounding to the nearest number 2:: Rounding towards positive infinity 3:: Rounding towards negative infinity
Represents the rounding mode for floating point addition. Usually defaults to 1, rounding to the nearest number. Other modes include
- RADIX =
The base of the floating point, or number of unique digits used to represent the number.
Usually defaults to 2 on most systems, which would represent a base-10 decimal.
INT2FIX(FLT_RADIX)
- MANT_DIG =
The number of base digits for the
double
data type.Usually defaults to 53.
INT2FIX(DBL_MANT_DIG)
- DIG =
The number of decimal digits in a double-precision floating point.
Usually defaults to 15.
INT2FIX(DBL_DIG)
- MIN_EXP =
The smallest posable exponent value in a double-precision floating point.
Usually defaults to -1021.
INT2FIX(DBL_MIN_EXP)
- MAX_EXP =
The largest possible exponent value in a double-precision floating point.
Usually defaults to 1024.
INT2FIX(DBL_MAX_EXP)
- MIN_10_EXP =
The smallest negative exponent in a double-precision floating point where 10 raised to this power minus 1.
Usually defaults to -307.
INT2FIX(DBL_MIN_10_EXP)
- MAX_10_EXP =
The largest positive exponent in a double-precision floating point where 10 raised to this power minus 1.
Usually defaults to 308.
INT2FIX(DBL_MAX_10_EXP)
- MIN =
The smallest positive integer in a double-precision floating point.
Usually defaults to 2.2250738585072014e-308.
DBL2NUM(DBL_MIN)
- MAX =
The largest possible integer in a double-precision floating point number.
Usually defaults to 1.7976931348623157e+308.
DBL2NUM(DBL_MAX)
- EPSILON =
The difference between 1 and the smallest double-precision floating point number.
Usually defaults to 2.2204460492503131e-16.
DBL2NUM(DBL_EPSILON)
- INFINITY =
An expression representing positive infinity.
DBL2NUM(INFINITY)
- NAN =
An expression representing a value which is “not a number”.
DBL2NUM(NAN)
Instance Method Summary collapse
-
#% ⇒ Object
Return the modulo after division of
float
byother
. -
#*(other) ⇒ Float
Returns a new float which is the product of
float
andother
. -
#**(other) ⇒ Float
Raises
float
to the power ofother
. -
#+(other) ⇒ Float
Returns a new float which is the sum of
float
andother
. -
#-(other) ⇒ Float
Returns a new float which is the difference of
float
andother
. -
#- ⇒ Float
Returns float, negated.
-
#/(other) ⇒ Float
Returns a new float which is the result of dividing
float
byother
. -
#<(real) ⇒ Boolean
Returns
true
iffloat
is less thanreal
. -
#<=(real) ⇒ Boolean
Returns
true
iffloat
is less than or equal toreal
. -
#<=>(real) ⇒ -1, ...
Returns -1, 0, +1 or nil depending on whether
float
is less than, equal to, or greater thanreal
. -
#==(obj) ⇒ Boolean
Returns
true
only ifobj
has the same value asfloat
. -
#==(obj) ⇒ Boolean
Returns
true
only ifobj
has the same value asfloat
. -
#>(real) ⇒ Boolean
Returns
true
iffloat
is greater thanreal
. -
#>=(real) ⇒ Boolean
Returns
true
iffloat
is greater than or equal toreal
. -
#abs ⇒ Object
Returns the absolute value of
float
. -
#angle ⇒ Object
Returns 0 if the value is positive, pi otherwise.
-
#arg ⇒ Object
Returns 0 if the value is positive, pi otherwise.
-
#ceil ⇒ Integer
Returns the smallest Integer greater than or equal to
float
. -
#coerce(numeric) ⇒ Array
Returns an array with both a
numeric
and afloat
represented as Float objects. -
#denominator ⇒ Integer
Returns the denominator (always positive).
-
#divmod(numeric) ⇒ Array
See Numeric#divmod.
-
#eql?(obj) ⇒ Boolean
Returns
true
only ifobj
is a Float with the same value asfloat
. -
#fdiv ⇒ Object
Returns
float / numeric
, same as Float#/. -
#finite? ⇒ Boolean
Returns
true
iffloat
is a valid IEEE floating point number (it is not infinite, and Float#nan? isfalse
). -
#floor ⇒ Integer
Returns the largest integer less than or equal to
float
. -
#hash ⇒ Integer
Returns a hash code for this float.
-
#infinite? ⇒ nil, ...
Return values corresponding to the value of
float
:. -
#magnitude ⇒ Object
Returns the absolute value of
float
. -
#modulo ⇒ Object
Return the modulo after division of
float
byother
. -
#nan? ⇒ Boolean
Returns
true
iffloat
is an invalid IEEE floating point number. -
#numerator ⇒ Integer
Returns the numerator.
-
#phase ⇒ Object
Returns 0 if the value is positive, pi otherwise.
-
#quo ⇒ Object
Returns
float / numeric
, same as Float#/. -
#rationalize([eps]) ⇒ Object
Returns a simpler approximation of the value (flt-|eps| <= result <= flt+|eps|).
-
#round([ndigits]) ⇒ Integer, Float
Rounds
float
to a given precision in decimal digits (default 0 digits). -
#to_f ⇒ self
Since
float
is already a float, returnsself
. -
#to_i ⇒ Object
Returns the
float
truncated to an Integer. -
#to_int ⇒ Object
Returns the
float
truncated to an Integer. -
#to_r ⇒ Object
Returns the value as a rational.
-
#to_s ⇒ String
(also: #inspect)
Returns a string containing a representation of self.
-
#truncate ⇒ Object
Returns the
float
truncated to an Integer. -
#zero? ⇒ Boolean
Returns
true
iffloat
is 0.0.
Methods inherited from Numeric
#+@, #abs2, #conj, #conjugate, #div, #i, #imag, #imaginary, #initialize_copy, #integer?, #nonzero?, #polar, #real, #real?, #rect, #rectangular, #remainder, #singleton_method_added, #step, #to_c
Methods included from Comparable
Instance Method Details
#%(other) ⇒ Float #modulo(other) ⇒ Float
Return the modulo after division of float
by other
.
6543.21.modulo(137) #=> 104.21
6543.21.modulo(137.24) #=> 92.9299999999996
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# File 'numeric.c', line 926
static VALUE
flo_mod(VALUE x, VALUE y)
{
double fy;
if (RB_TYPE_P(y, T_FIXNUM)) {
fy = (double)FIX2LONG(y);
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
fy = rb_big2dbl(y);
}
else if (RB_TYPE_P(y, T_FLOAT)) {
fy = RFLOAT_VALUE(y);
}
else {
return rb_num_coerce_bin(x, y, '%');
}
return DBL2NUM(ruby_float_mod(RFLOAT_VALUE(x), fy));
}
|
#*(other) ⇒ Float
Returns a new float which is the product of float
and other
.
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# File 'numeric.c', line 811
static VALUE
flo_mul(VALUE x, VALUE y)
{
if (RB_TYPE_P(y, T_FIXNUM)) {
return DBL2NUM(RFLOAT_VALUE(x) * (double)FIX2LONG(y));
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
return DBL2NUM(RFLOAT_VALUE(x) * rb_big2dbl(y));
}
else if (RB_TYPE_P(y, T_FLOAT)) {
return DBL2NUM(RFLOAT_VALUE(x) * RFLOAT_VALUE(y));
}
else {
return rb_num_coerce_bin(x, y, '*');
}
}
|
#**(other) ⇒ Float
Raises float
to the power of other
.
2.0**3 #=> 8.0
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# File 'numeric.c', line 1000
static VALUE
flo_pow(VALUE x, VALUE y)
{
if (RB_TYPE_P(y, T_FIXNUM)) {
return DBL2NUM(pow(RFLOAT_VALUE(x), (double)FIX2LONG(y)));
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
return DBL2NUM(pow(RFLOAT_VALUE(x), rb_big2dbl(y)));
}
else if (RB_TYPE_P(y, T_FLOAT)) {
{
double dx = RFLOAT_VALUE(x);
double dy = RFLOAT_VALUE(y);
if (dx < 0 && dy != round(dy))
return rb_funcall(rb_complex_raw1(x), rb_intern("**"), 1, y);
return DBL2NUM(pow(dx, dy));
}
}
else {
return rb_num_coerce_bin(x, y, rb_intern("**"));
}
}
|
#+(other) ⇒ Float
Returns a new float which is the sum of float
and other
.
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# File 'numeric.c', line 763
static VALUE
flo_plus(VALUE x, VALUE y)
{
if (RB_TYPE_P(y, T_FIXNUM)) {
return DBL2NUM(RFLOAT_VALUE(x) + (double)FIX2LONG(y));
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
return DBL2NUM(RFLOAT_VALUE(x) + rb_big2dbl(y));
}
else if (RB_TYPE_P(y, T_FLOAT)) {
return DBL2NUM(RFLOAT_VALUE(x) + RFLOAT_VALUE(y));
}
else {
return rb_num_coerce_bin(x, y, '+');
}
}
|
#-(other) ⇒ Float
Returns a new float which is the difference of float
and other
.
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# File 'numeric.c', line 787
static VALUE
flo_minus(VALUE x, VALUE y)
{
if (RB_TYPE_P(y, T_FIXNUM)) {
return DBL2NUM(RFLOAT_VALUE(x) - (double)FIX2LONG(y));
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
return DBL2NUM(RFLOAT_VALUE(x) - rb_big2dbl(y));
}
else if (RB_TYPE_P(y, T_FLOAT)) {
return DBL2NUM(RFLOAT_VALUE(x) - RFLOAT_VALUE(y));
}
else {
return rb_num_coerce_bin(x, y, '-');
}
}
|
#- ⇒ Float
Returns float, negated.
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# File 'numeric.c', line 750
static VALUE
flo_uminus(VALUE flt)
{
return DBL2NUM(-RFLOAT_VALUE(flt));
}
|
#/(other) ⇒ Float
Returns a new float which is the result of dividing float
by other
.
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# File 'numeric.c', line 835
static VALUE
flo_div(VALUE x, VALUE y)
{
long f_y;
double d;
if (RB_TYPE_P(y, T_FIXNUM)) {
f_y = FIX2LONG(y);
return DBL2NUM(RFLOAT_VALUE(x) / (double)f_y);
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
d = rb_big2dbl(y);
return DBL2NUM(RFLOAT_VALUE(x) / d);
}
else if (RB_TYPE_P(y, T_FLOAT)) {
return DBL2NUM(RFLOAT_VALUE(x) / RFLOAT_VALUE(y));
}
else {
return rb_num_coerce_bin(x, y, '/');
}
}
|
#<(real) ⇒ Boolean
Returns true
if float
is less than real
.
The result of NaN < NaN
is undefined, so the implementation-dependent value is returned.
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# File 'numeric.c', line 1262
static VALUE
flo_lt(VALUE x, VALUE y)
{
double a, b;
a = RFLOAT_VALUE(x);
if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
VALUE rel = rb_integer_float_cmp(y, x);
if (FIXNUM_P(rel))
return -FIX2INT(rel) < 0 ? Qtrue : Qfalse;
return Qfalse;
}
else if (RB_TYPE_P(y, T_FLOAT)) {
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
}
else {
return rb_num_coerce_relop(x, y, '<');
}
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(a)) return Qfalse;
#endif
return (a < b)?Qtrue:Qfalse;
}
|
#<=(real) ⇒ Boolean
Returns true
if float
is less than or equal to real
.
The result of NaN <= NaN
is undefined, so the implementation-dependent value is returned.
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# File 'numeric.c', line 1299
static VALUE
flo_le(VALUE x, VALUE y)
{
double a, b;
a = RFLOAT_VALUE(x);
if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
VALUE rel = rb_integer_float_cmp(y, x);
if (FIXNUM_P(rel))
return -FIX2INT(rel) <= 0 ? Qtrue : Qfalse;
return Qfalse;
}
else if (RB_TYPE_P(y, T_FLOAT)) {
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
}
else {
return rb_num_coerce_relop(x, y, rb_intern("<="));
}
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(a)) return Qfalse;
#endif
return (a <= b)?Qtrue:Qfalse;
}
|
#<=>(real) ⇒ -1, ...
Returns -1, 0, +1 or nil depending on whether float
is less than, equal to, or greater than real
. This is the basis for the tests in Comparable.
The result of NaN <=> NaN
is undefined, so the implementation-dependent value is returned.
nil
is returned if the two values are incomparable.
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# File 'numeric.c', line 1146
static VALUE
flo_cmp(VALUE x, VALUE y)
{
double a, b;
VALUE i;
a = RFLOAT_VALUE(x);
if (isnan(a)) return Qnil;
if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
VALUE rel = rb_integer_float_cmp(y, x);
if (FIXNUM_P(rel))
return INT2FIX(-FIX2INT(rel));
return rel;
}
else if (RB_TYPE_P(y, T_FLOAT)) {
b = RFLOAT_VALUE(y);
}
else {
if (isinf(a) && (i = rb_check_funcall(y, rb_intern("infinite?"), 0, 0)) != Qundef) {
if (RTEST(i)) {
int j = rb_cmpint(i, x, y);
j = (a > 0.0) ? (j > 0 ? 0 : +1) : (j < 0 ? 0 : -1);
return INT2FIX(j);
}
if (a > 0.0) return INT2FIX(1);
return INT2FIX(-1);
}
return rb_num_coerce_cmp(x, y, id_cmp);
}
return rb_dbl_cmp(a, b);
}
|
#==(obj) ⇒ Boolean
Returns true
only if obj
has the same value as float
. Contrast this with Float#eql?, which requires obj to be a Float.
The result of NaN == NaN
is undefined, so the implementation-dependent value is returned.
1.0 == 1 #=> true
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# File 'numeric.c', line 1079
static VALUE
flo_eq(VALUE x, VALUE y)
{
volatile double a, b;
if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
return rb_integer_float_eq(y, x);
}
else if (RB_TYPE_P(y, T_FLOAT)) {
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
}
else {
return num_equal(x, y);
}
a = RFLOAT_VALUE(x);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(a)) return Qfalse;
#endif
return (a == b)?Qtrue:Qfalse;
}
|
#==(obj) ⇒ Boolean
Returns true
only if obj
has the same value as float
. Contrast this with Float#eql?, which requires obj to be a Float.
The result of NaN == NaN
is undefined, so the implementation-dependent value is returned.
1.0 == 1 #=> true
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# File 'numeric.c', line 1079
static VALUE
flo_eq(VALUE x, VALUE y)
{
volatile double a, b;
if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
return rb_integer_float_eq(y, x);
}
else if (RB_TYPE_P(y, T_FLOAT)) {
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
}
else {
return num_equal(x, y);
}
a = RFLOAT_VALUE(x);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(a)) return Qfalse;
#endif
return (a == b)?Qtrue:Qfalse;
}
|
#>(real) ⇒ Boolean
Returns true
if float
is greater than real
.
The result of NaN > NaN
is undefined, so the implementation-dependent value is returned.
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# File 'numeric.c', line 1188
static VALUE
flo_gt(VALUE x, VALUE y)
{
double a, b;
a = RFLOAT_VALUE(x);
if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
VALUE rel = rb_integer_float_cmp(y, x);
if (FIXNUM_P(rel))
return -FIX2INT(rel) > 0 ? Qtrue : Qfalse;
return Qfalse;
}
else if (RB_TYPE_P(y, T_FLOAT)) {
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
}
else {
return rb_num_coerce_relop(x, y, '>');
}
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(a)) return Qfalse;
#endif
return (a > b)?Qtrue:Qfalse;
}
|
#>=(real) ⇒ Boolean
Returns true
if float
is greater than or equal to real
.
The result of NaN >= NaN
is undefined, so the implementation-dependent value is returned.
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# File 'numeric.c', line 1225
static VALUE
flo_ge(VALUE x, VALUE y)
{
double a, b;
a = RFLOAT_VALUE(x);
if (RB_TYPE_P(y, T_FIXNUM) || RB_TYPE_P(y, T_BIGNUM)) {
VALUE rel = rb_integer_float_cmp(y, x);
if (FIXNUM_P(rel))
return -FIX2INT(rel) >= 0 ? Qtrue : Qfalse;
return Qfalse;
}
else if (RB_TYPE_P(y, T_FLOAT)) {
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
}
else {
return rb_num_coerce_relop(x, y, rb_intern(">="));
}
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(a)) return Qfalse;
#endif
return (a >= b)?Qtrue:Qfalse;
}
|
#abs ⇒ Float #magnitude ⇒ Float
Returns the absolute value of float
.
(-34.56).abs #=> 34.56
-34.56.abs #=> 34.56
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# File 'numeric.c', line 1379
static VALUE
flo_abs(VALUE flt)
{
double val = fabs(RFLOAT_VALUE(flt));
return DBL2NUM(val);
}
|
#arg ⇒ 0, Float #angle ⇒ 0, Float #phase ⇒ 0, Float
Returns 0 if the value is positive, pi otherwise.
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# File 'complex.c', line 2007
static VALUE
float_arg(VALUE self)
{
if (isnan(RFLOAT_VALUE(self)))
return self;
if (f_tpositive_p(self))
return INT2FIX(0);
return rb_const_get(rb_mMath, id_PI);
}
|
#arg ⇒ 0, Float #angle ⇒ 0, Float #phase ⇒ 0, Float
Returns 0 if the value is positive, pi otherwise.
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# File 'complex.c', line 2007
static VALUE
float_arg(VALUE self)
{
if (isnan(RFLOAT_VALUE(self)))
return self;
if (f_tpositive_p(self))
return INT2FIX(0);
return rb_const_get(rb_mMath, id_PI);
}
|
#ceil ⇒ Integer
Returns the smallest Integer greater than or equal to float
.
1.2.ceil #=> 2
2.0.ceil #=> 2
(-1.2).ceil #=> -1
(-2.0).ceil #=> -2
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# File 'numeric.c', line 1514
static VALUE
flo_ceil(VALUE num)
{
double f = ceil(RFLOAT_VALUE(num));
long val;
if (!FIXABLE(f)) {
return rb_dbl2big(f);
}
val = (long)f;
return LONG2FIX(val);
}
|
#coerce(numeric) ⇒ Array
Returns an array with both a numeric
and a float
represented as Float objects.
This is achieved by converting a numeric
to a Float.
1.2.coerce(3) #=> [3.0, 1.2]
2.5.coerce(1.1) #=> [1.1, 2.5]
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# File 'numeric.c', line 737
static VALUE
flo_coerce(VALUE x, VALUE y)
{
return rb_assoc_new(rb_Float(y), x);
}
|
#denominator ⇒ Integer
Returns the denominator (always positive). The result is machine dependent.
See numerator.
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# File 'rational.c', line 1892
static VALUE
float_denominator(VALUE self)
{
double d = RFLOAT_VALUE(self);
if (isinf(d) || isnan(d))
return INT2FIX(1);
return rb_call_super(0, 0);
}
|
#divmod(numeric) ⇒ Array
See Numeric#divmod.
42.0.divmod 6 #=> [7, 0.0]
42.0.divmod 5 #=> [8, 2.0]
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# File 'numeric.c', line 966
static VALUE
flo_divmod(VALUE x, VALUE y)
{
double fy, div, mod;
volatile VALUE a, b;
if (RB_TYPE_P(y, T_FIXNUM)) {
fy = (double)FIX2LONG(y);
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
fy = rb_big2dbl(y);
}
else if (RB_TYPE_P(y, T_FLOAT)) {
fy = RFLOAT_VALUE(y);
}
else {
return rb_num_coerce_bin(x, y, rb_intern("divmod"));
}
flodivmod(RFLOAT_VALUE(x), fy, &div, &mod);
a = dbl2ival(div);
b = DBL2NUM(mod);
return rb_assoc_new(a, b);
}
|
#eql?(obj) ⇒ Boolean
Returns true
only if obj
is a Float with the same value as float
. Contrast this with Float#==, which performs type conversions.
The result of NaN.eql?(NaN)
is undefined, so the implementation-dependent value is returned.
1.0.eql?(1) #=> false
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# File 'numeric.c', line 1339
static VALUE
flo_eql(VALUE x, VALUE y)
{
if (RB_TYPE_P(y, T_FLOAT)) {
double a = RFLOAT_VALUE(x);
double b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(a) || isnan(b)) return Qfalse;
#endif
if (a == b)
return Qtrue;
}
return Qfalse;
}
|
#fdiv(numeric) ⇒ Float #quo(numeric) ⇒ Float
Returns float / numeric
, same as Float#/.
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# File 'numeric.c', line 865
static VALUE
flo_quo(VALUE x, VALUE y)
{
return rb_funcall(x, '/', 1, y);
}
|
#finite? ⇒ Boolean
Returns true
if float
is a valid IEEE floating point number (it is not infinite, and Float#nan? is false
).
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# File 'numeric.c', line 1461
static VALUE
flo_is_finite_p(VALUE num)
{
double value = RFLOAT_VALUE(num);
#if HAVE_ISFINITE
if (!isfinite(value))
return Qfalse;
#else
if (isinf(value) || isnan(value))
return Qfalse;
#endif
return Qtrue;
}
|
#floor ⇒ Integer
Returns the largest integer less than or equal to float
.
1.2.floor #=> 1
2.0.floor #=> 2
(-1.2).floor #=> -2
(-2.0).floor #=> -2
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# File 'numeric.c', line 1489
static VALUE
flo_floor(VALUE num)
{
double f = floor(RFLOAT_VALUE(num));
long val;
if (!FIXABLE(f)) {
return rb_dbl2big(f);
}
val = (long)f;
return LONG2FIX(val);
}
|
#hash ⇒ Integer
Returns a hash code for this float.
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# File 'numeric.c', line 1110
static VALUE
flo_hash(VALUE num)
{
double d;
st_index_t hash;
d = RFLOAT_VALUE(num);
/* normalize -0.0 to 0.0 */
if (d == 0.0) d = 0.0;
hash = rb_memhash(&d, sizeof(d));
return LONG2FIX(hash);
}
|
#infinite? ⇒ nil, ...
Return values corresponding to the value of float
:
finite
:: nil
-Infinity
-
-1
+Infinity
-
1
For example:
(0.0).infinite? #=> nil
(-1.0/0.0).infinite? #=> -1
(+1.0/0.0).infinite? #=> 1
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# File 'numeric.c', line 1440
static VALUE
flo_is_infinite_p(VALUE num)
{
double value = RFLOAT_VALUE(num);
if (isinf(value)) {
return INT2FIX( value < 0 ? -1 : 1 );
}
return Qnil;
}
|
#abs ⇒ Float #magnitude ⇒ Float
Returns the absolute value of float
.
(-34.56).abs #=> 34.56
-34.56.abs #=> 34.56
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# File 'numeric.c', line 1379
static VALUE
flo_abs(VALUE flt)
{
double val = fabs(RFLOAT_VALUE(flt));
return DBL2NUM(val);
}
|
#%(other) ⇒ Float #modulo(other) ⇒ Float
Return the modulo after division of float
by other
.
6543.21.modulo(137) #=> 104.21
6543.21.modulo(137.24) #=> 92.9299999999996
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# File 'numeric.c', line 926
static VALUE
flo_mod(VALUE x, VALUE y)
{
double fy;
if (RB_TYPE_P(y, T_FIXNUM)) {
fy = (double)FIX2LONG(y);
}
else if (RB_TYPE_P(y, T_BIGNUM)) {
fy = rb_big2dbl(y);
}
else if (RB_TYPE_P(y, T_FLOAT)) {
fy = RFLOAT_VALUE(y);
}
else {
return rb_num_coerce_bin(x, y, '%');
}
return DBL2NUM(ruby_float_mod(RFLOAT_VALUE(x), fy));
}
|
#nan? ⇒ Boolean
Returns true
if float
is an invalid IEEE floating point number.
a = -1.0 #=> -1.0
a.nan? #=> false
a = 0.0/0.0 #=> NaN
a.nan? #=> true
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# File 'numeric.c', line 1415
static VALUE
flo_is_nan_p(VALUE num)
{
double value = RFLOAT_VALUE(num);
return isnan(value) ? Qtrue : Qfalse;
}
|
#numerator ⇒ Integer
Returns the numerator. The result is machine dependent.
n = 0.3.numerator #=> 5404319552844595
d = 0.3.denominator #=> 18014398509481984
n.fdiv(d) #=> 0.3
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# File 'rational.c', line 1874
static VALUE
float_numerator(VALUE self)
{
double d = RFLOAT_VALUE(self);
if (isinf(d) || isnan(d))
return self;
return rb_call_super(0, 0);
}
|
#arg ⇒ 0, Float #angle ⇒ 0, Float #phase ⇒ 0, Float
Returns 0 if the value is positive, pi otherwise.
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# File 'complex.c', line 2007
static VALUE
float_arg(VALUE self)
{
if (isnan(RFLOAT_VALUE(self)))
return self;
if (f_tpositive_p(self))
return INT2FIX(0);
return rb_const_get(rb_mMath, id_PI);
}
|
#fdiv(numeric) ⇒ Float #quo(numeric) ⇒ Float
Returns float / numeric
, same as Float#/.
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# File 'numeric.c', line 865
static VALUE
flo_quo(VALUE x, VALUE y)
{
return rb_funcall(x, '/', 1, y);
}
|
#rationalize([eps]) ⇒ Object
Returns a simpler approximation of the value (flt-|eps| <= result <= flt+|eps|). if the optional eps is not given, it will be chosen automatically.
0.3.rationalize #=> (3/10)
1.333.rationalize #=> (1333/1000)
1.333.rationalize(0.01) #=> (4/3)
See to_r.
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# File 'rational.c', line 2089
static VALUE
float_rationalize(int argc, VALUE *argv, VALUE self)
{
VALUE e;
if (f_negative_p(self))
return f_negate(float_rationalize(argc, argv, f_abs(self)));
rb_scan_args(argc, argv, "01", &e);
if (argc != 0) {
return rb_flt_rationalize_with_prec(self, e);
}
else {
return rb_flt_rationalize(self);
}
}
|
#round([ndigits]) ⇒ Integer, Float
Rounds float
to a given precision in decimal digits (default 0 digits).
Precision may be negative. Returns a floating point number when ndigits
is more than zero.
1.4.round #=> 1
1.5.round #=> 2
1.6.round #=> 2
(-1.5).round #=> -2
1.234567.round(2) #=> 1.23
1.234567.round(3) #=> 1.235
1.234567.round(4) #=> 1.2346
1.234567.round(5) #=> 1.23457
34567.89.round(-5) #=> 0
34567.89.round(-4) #=> 30000
34567.89.round(-3) #=> 35000
34567.89.round(-2) #=> 34600
34567.89.round(-1) #=> 34570
34567.89.round(0) #=> 34568
34567.89.round(1) #=> 34567.9
34567.89.round(2) #=> 34567.89
34567.89.round(3) #=> 34567.89
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# File 'numeric.c', line 1600
static VALUE
flo_round(int argc, VALUE *argv, VALUE num)
{
VALUE nd;
double number, f;
int ndigits = 0;
int binexp;
enum {float_dig = DBL_DIG+2};
if (argc > 0 && rb_scan_args(argc, argv, "01", &nd) == 1) {
ndigits = NUM2INT(nd);
}
if (ndigits < 0) {
return int_round_0(flo_truncate(num), ndigits);
}
number = RFLOAT_VALUE(num);
if (ndigits == 0) {
return dbl2ival(number);
}
frexp(number, &binexp);
/* Let `exp` be such that `number` is written as:"0.#{digits}e#{exp}",
i.e. such that 10 ** (exp - 1) <= |number| < 10 ** exp
Recall that up to float_dig digits can be needed to represent a double,
so if ndigits + exp >= float_dig, the intermediate value (number * 10 ** ndigits)
will be an integer and thus the result is the original number.
If ndigits + exp <= 0, the result is 0 or "1e#{exp}", so
if ndigits + exp < 0, the result is 0.
We have:
2 ** (binexp-1) <= |number| < 2 ** binexp
10 ** ((binexp-1)/log_2(10)) <= |number| < 10 ** (binexp/log_2(10))
If binexp >= 0, and since log_2(10) = 3.322259:
10 ** (binexp/4 - 1) < |number| < 10 ** (binexp/3)
floor(binexp/4) <= exp <= ceil(binexp/3)
If binexp <= 0, swap the /4 and the /3
So if ndigits + floor(binexp/(4 or 3)) >= float_dig, the result is number
If ndigits + ceil(binexp/(3 or 4)) < 0 the result is 0
*/
if (isinf(number) || isnan(number) ||
(ndigits >= float_dig - (binexp > 0 ? binexp / 4 : binexp / 3 - 1))) {
return num;
}
if (ndigits < - (binexp > 0 ? binexp / 3 + 1 : binexp / 4)) {
return DBL2NUM(0);
}
f = pow(10, ndigits);
return DBL2NUM(round(number * f) / f);
}
|
#to_f ⇒ self
Since float
is already a float, returns self
.
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# File 'numeric.c', line 1361
static VALUE
flo_to_f(VALUE num)
{
return num;
}
|
#to_i ⇒ Integer #to_int ⇒ Integer #truncate ⇒ Integer
Returns the float
truncated to an Integer.
Synonyms are #to_i, #to_int, and #truncate.
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# File 'numeric.c', line 1660
static VALUE
flo_truncate(VALUE num)
{
double f = RFLOAT_VALUE(num);
long val;
if (f > 0.0) f = floor(f);
if (f < 0.0) f = ceil(f);
if (!FIXABLE(f)) {
return rb_dbl2big(f);
}
val = (long)f;
return LONG2FIX(val);
}
|
#to_i ⇒ Integer #to_int ⇒ Integer #truncate ⇒ Integer
Returns the float
truncated to an Integer.
Synonyms are #to_i, #to_int, and #truncate.
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# File 'numeric.c', line 1660
static VALUE
flo_truncate(VALUE num)
{
double f = RFLOAT_VALUE(num);
long val;
if (f > 0.0) f = floor(f);
if (f < 0.0) f = ceil(f);
if (!FIXABLE(f)) {
return rb_dbl2big(f);
}
val = (long)f;
return LONG2FIX(val);
}
|
#to_r ⇒ Object
Returns the value as a rational.
NOTE: 0.3.to_r isn’t the same as ‘0.3’.to_r. The latter is equivalent to ‘3/10’.to_r, but the former isn’t so.
2.0.to_r #=> (2/1)
2.5.to_r #=> (5/2)
-0.75.to_r #=> (-3/4)
0.0.to_r #=> (0/1)
See rationalize.
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# File 'rational.c', line 1999
static VALUE
float_to_r(VALUE self)
{
VALUE f, n;
float_decode_internal(self, &f, &n);
#if FLT_RADIX == 2
{
long ln = FIX2LONG(n);
if (ln == 0)
return f_to_r(f);
if (ln > 0)
return f_to_r(f_lshift(f, n));
ln = -ln;
return rb_rational_new2(f, f_lshift(ONE, INT2FIX(ln)));
}
#else
return f_to_r(f_mul(f, f_expt(INT2FIX(FLT_RADIX), n)));
#endif
}
|
#to_s ⇒ String Also known as: inspect
Returns a string containing a representation of self. As well as a fixed or exponential form of the float
, the call may return NaN
, Infinity
, and -Infinity
.
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# File 'numeric.c', line 655
static VALUE
flo_to_s(VALUE flt)
{
char *ruby_dtoa(double d_, int mode, int ndigits, int *decpt, int *sign, char **rve);
enum {decimal_mant = DBL_MANT_DIG-DBL_DIG};
enum {float_dig = DBL_DIG+1};
char buf[float_dig + (decimal_mant + CHAR_BIT - 1) / CHAR_BIT + 10];
double value = RFLOAT_VALUE(flt);
VALUE s;
char *p, *e;
int sign, decpt, digs;
if (isinf(value))
return rb_usascii_str_new2(value < 0 ? "-Infinity" : "Infinity");
else if (isnan(value))
return rb_usascii_str_new2("NaN");
p = ruby_dtoa(value, 0, 0, &decpt, &sign, &e);
s = sign ? rb_usascii_str_new_cstr("-") : rb_usascii_str_new(0, 0);
if ((digs = (int)(e - p)) >= (int)sizeof(buf)) digs = (int)sizeof(buf) - 1;
memcpy(buf, p, digs);
xfree(p);
if (decpt > 0) {
if (decpt < digs) {
memmove(buf + decpt + 1, buf + decpt, digs - decpt);
buf[decpt] = '.';
rb_str_cat(s, buf, digs + 1);
}
else if (decpt <= DBL_DIG) {
long len;
char *ptr;
rb_str_cat(s, buf, digs);
rb_str_resize(s, (len = RSTRING_LEN(s)) + decpt - digs + 2);
ptr = RSTRING_PTR(s) + len;
if (decpt > digs) {
memset(ptr, '0', decpt - digs);
ptr += decpt - digs;
}
memcpy(ptr, ".0", 2);
}
else {
goto exp;
}
}
else if (decpt > -4) {
long len;
char *ptr;
rb_str_cat(s, "0.", 2);
rb_str_resize(s, (len = RSTRING_LEN(s)) - decpt + digs);
ptr = RSTRING_PTR(s);
memset(ptr += len, '0', -decpt);
memcpy(ptr -= decpt, buf, digs);
}
else {
exp:
if (digs > 1) {
memmove(buf + 2, buf + 1, digs - 1);
}
else {
buf[2] = '0';
digs++;
}
buf[1] = '.';
rb_str_cat(s, buf, digs + 1);
rb_str_catf(s, "e%+03d", decpt - 1);
}
return s;
}
|
#to_i ⇒ Integer #to_int ⇒ Integer #truncate ⇒ Integer
Returns the float
truncated to an Integer.
Synonyms are #to_i, #to_int, and #truncate.
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# File 'numeric.c', line 1660
static VALUE
flo_truncate(VALUE num)
{
double f = RFLOAT_VALUE(num);
long val;
if (f > 0.0) f = floor(f);
if (f < 0.0) f = ceil(f);
if (!FIXABLE(f)) {
return rb_dbl2big(f);
}
val = (long)f;
return LONG2FIX(val);
}
|
#zero? ⇒ Boolean
Returns true
if float
is 0.0.
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# File 'numeric.c', line 1394
static VALUE
flo_zero_p(VALUE num)
{
if (RFLOAT_VALUE(num) == 0.0) {
return Qtrue;
}
return Qfalse;
}
|