Class: Float

Inherits:
Numeric show all
Defined in:
numeric.c

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 a inexact number. So you should know its esoteric system. see following:

Constant Summary collapse

ROUNDS = 
INT2FIX(FLT_ROUNDS)
RADIX = 
INT2FIX(FLT_RADIX)
MANT_DIG = 
INT2FIX(DBL_MANT_DIG)
DIG = 
INT2FIX(DBL_DIG)
MIN_EXP = 
INT2FIX(DBL_MIN_EXP)
MAX_EXP = 
INT2FIX(DBL_MAX_EXP)
MIN_10_EXP = 
INT2FIX(DBL_MIN_10_EXP)
MAX_10_EXP = 
INT2FIX(DBL_MAX_10_EXP)
MIN = 
DBL2NUM(DBL_MIN)
MAX = 
DBL2NUM(DBL_MAX)
EPSILON = 
DBL2NUM(DBL_EPSILON)
INFINITY = 
DBL2NUM(INFINITY)
NAN = 
DBL2NUM(NAN)

Instance Method Summary collapse

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

#between?

Instance Method Details

#%(other) ⇒ Float #modulo(other) ⇒ Float

Return the modulo after division of flt by other.

6543.21.modulo(137)      #=> 104.21
6543.21.modulo(137.24)   #=> 92.9299999999996

Overloads:




# File 'numeric.c'

static VALUE
flo_mod(VALUE x, VALUE y)
{
double fy;

switch (TYPE(y)) {
  case T_FIXNUM:
fy = (double)FIX2LONG(y);
break;
  case T_BIGNUM:
fy = rb_big2dbl(y);
break;
  case T_FLOAT:
fy = RFLOAT_VALUE(y);
break;
  default:
return rb_num_coerce_bin(x, y, '%');
}

#*(other) ⇒ Float

Returns a new float which is the product of float and other.

Returns:




# File 'numeric.c'

static VALUE
flo_mul(VALUE x, VALUE y)
{
switch (TYPE(y)) {
  case T_FIXNUM:
return DBL2NUM(RFLOAT_VALUE(x) * (double)FIX2LONG(y));
  case T_BIGNUM:
return DBL2NUM(RFLOAT_VALUE(x) * rb_big2dbl(y));
  case T_FLOAT:
return DBL2NUM(RFLOAT_VALUE(x) * RFLOAT_VALUE(y));
  default:
return rb_num_coerce_bin(x, y, '*');
}

#**(other) ⇒ Float

Raises float the other power.

2.0**3      #=> 8.0

Returns:




# File 'numeric.c'

static VALUE
flo_pow(VALUE x, VALUE y)
{
switch (TYPE(y)) {
  case T_FIXNUM:
return DBL2NUM(pow(RFLOAT_VALUE(x), (double)FIX2LONG(y)));
  case T_BIGNUM:
return DBL2NUM(pow(RFLOAT_VALUE(x), rb_big2dbl(y)));
  case 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));
}

#+(other) ⇒ Float

Returns a new float which is the sum of float and other.

Returns:




# File 'numeric.c'

static VALUE
flo_plus(VALUE x, VALUE y)
{
switch (TYPE(y)) {
  case T_FIXNUM:
return DBL2NUM(RFLOAT_VALUE(x) + (double)FIX2LONG(y));
  case T_BIGNUM:
return DBL2NUM(RFLOAT_VALUE(x) + rb_big2dbl(y));
  case T_FLOAT:
return DBL2NUM(RFLOAT_VALUE(x) + RFLOAT_VALUE(y));
  default:
return rb_num_coerce_bin(x, y, '+');
}

#-(other) ⇒ Float

Returns a new float which is the difference of float and other.

Returns:




# File 'numeric.c'

static VALUE
flo_minus(VALUE x, VALUE y)
{
switch (TYPE(y)) {
  case T_FIXNUM:
return DBL2NUM(RFLOAT_VALUE(x) - (double)FIX2LONG(y));
  case T_BIGNUM:
return DBL2NUM(RFLOAT_VALUE(x) - rb_big2dbl(y));
  case T_FLOAT:
return DBL2NUM(RFLOAT_VALUE(x) - RFLOAT_VALUE(y));
  default:
return rb_num_coerce_bin(x, y, '-');
}

#- ⇒ Float

Returns float, negated.

Returns:




# File 'numeric.c'

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.

Returns:




# File 'numeric.c'

static VALUE
flo_div(VALUE x, VALUE y)
{
long f_y;
double d;

switch (TYPE(y)) {
  case T_FIXNUM:
f_y = FIX2LONG(y);
return DBL2NUM(RFLOAT_VALUE(x) / (double)f_y);
  case T_BIGNUM:
d = rb_big2dbl(y);
return DBL2NUM(RFLOAT_VALUE(x) / d);
  case T_FLOAT:
return DBL2NUM(RFLOAT_VALUE(x) / RFLOAT_VALUE(y));
  default:
return rb_num_coerce_bin(x, y, '/');
}

#<(real) ⇒ Boolean

true if flt is less than real.

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_lt(VALUE x, VALUE y)
{
double a, b;

a = RFLOAT_VALUE(x);
switch (TYPE(y)) {
  case T_FIXNUM:
b = (double)FIX2LONG(y);
break;

  case T_BIGNUM:
b = rb_big2dbl(y);
break;

  case T_FLOAT:
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
break;

  default:
return rb_num_coerce_relop(x, y, '<');
}

#<=(real) ⇒ Boolean

true if flt is less than or equal to real.

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_le(VALUE x, VALUE y)
{
double a, b;

a = RFLOAT_VALUE(x);
switch (TYPE(y)) {
  case T_FIXNUM:
b = (double)FIX2LONG(y);
break;

  case T_BIGNUM:
b = rb_big2dbl(y);
break;

  case T_FLOAT:
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
break;

  default:
return rb_num_coerce_relop(x, y, rb_intern("<="));
}

#<=>(real) ⇒ -1, ...

Returns -1, 0, +1 or nil depending on whether flt is less than, equal to, or greater than real. This is the basis for the tests in Comparable.

Returns:

  • (-1, 0, +1, nil) 



# File 'numeric.c'

static VALUE
flo_cmp(VALUE x, VALUE y)
{
double a, b;
VALUE i;

a = RFLOAT_VALUE(x);
if (isnan(a)) return Qnil;
switch (TYPE(y)) {
  case T_FIXNUM:
b = (double)FIX2LONG(y);
break;

  case T_BIGNUM:
if (isinf(a)) {
    if (a > 0.0) return INT2FIX(1);
    else return INT2FIX(-1);
}

#==(obj) ⇒ Boolean

Returns true only if obj has the same value as flt. Contrast this with Float#eql?, which requires obj to be a Float.

1.0 == 1   #=> true

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_eq(VALUE x, VALUE y)
{
volatile double a, b;

switch (TYPE(y)) {
  case T_FIXNUM:
b = (double)FIX2LONG(y);
break;
  case T_BIGNUM:
b = rb_big2dbl(y);
break;
  case T_FLOAT:
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
break;
  default:
return num_equal(x, y);
}

#==(obj) ⇒ Boolean

Returns true only if obj has the same value as flt. Contrast this with Float#eql?, which requires obj to be a Float.

1.0 == 1   #=> true

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_eq(VALUE x, VALUE y)
{
volatile double a, b;

switch (TYPE(y)) {
  case T_FIXNUM:
b = (double)FIX2LONG(y);
break;
  case T_BIGNUM:
b = rb_big2dbl(y);
break;
  case T_FLOAT:
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
break;
  default:
return num_equal(x, y);
}

#>(real) ⇒ Boolean

true if flt is greater than real.

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_gt(VALUE x, VALUE y)
{
double a, b;

a = RFLOAT_VALUE(x);
switch (TYPE(y)) {
  case T_FIXNUM:
b = (double)FIX2LONG(y);
break;

  case T_BIGNUM:
b = rb_big2dbl(y);
break;

  case T_FLOAT:
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
break;

  default:
return rb_num_coerce_relop(x, y, '>');
}

#>=(real) ⇒ Boolean

true if flt is greater than or equal to real.

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_ge(VALUE x, VALUE y)
{
double a, b;

a = RFLOAT_VALUE(x);
switch (TYPE(y)) {
  case T_FIXNUM:
b = (double)FIX2LONG(y);
break;

  case T_BIGNUM:
b = rb_big2dbl(y);
break;

  case T_FLOAT:
b = RFLOAT_VALUE(y);
#if defined(_MSC_VER) && _MSC_VER < 1300
if (isnan(b)) return Qfalse;
#endif
break;

  default:
return rb_num_coerce_relop(x, y, rb_intern(">="));
}

#abs ⇒ Float #magnitude ⇒ Float

Returns the absolute value of flt.

(-34.56).abs   #=> 34.56
-34.56.abs     #=> 34.56

Overloads:




# File 'numeric.c'

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.

Overloads:




# File 'complex.c'

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.

Overloads:




# File 'complex.c'

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 flt.

1.2.ceil      #=> 2
2.0.ceil      #=> 2
(-1.2).ceil   #=> -1
(-2.0).ceil   #=> -2

Returns:




# File 'numeric.c'

static VALUE
flo_ceil(VALUE num)
{
double f = ceil(RFLOAT_VALUE(num));
long val;

if (!FIXABLE(f)) {
return rb_dbl2big(f);
}

#coerce(numeric) ⇒ Array

Returns an array with both aNumeric and flt represented as Float objects. This is achieved by converting aNumeric to a Float.

1.2.coerce(3)       #=> [3.0, 1.2]
2.5.coerce(1.1)     #=> [1.1, 2.5]

Returns:




# File 'numeric.c'

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.

Returns:




# File 'rational.c'

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.

Returns:




# File 'numeric.c'

static VALUE
flo_divmod(VALUE x, VALUE y)
{
double fy, div, mod;
volatile VALUE a, b;

switch (TYPE(y)) {
  case T_FIXNUM:
fy = (double)FIX2LONG(y);
break;
  case T_BIGNUM:
fy = rb_big2dbl(y);
break;
  case T_FLOAT:
fy = RFLOAT_VALUE(y);
break;
  default:
return rb_num_coerce_bin(x, y, rb_intern("divmod"));
}

#eql?(obj) ⇒ Boolean

Returns true only if obj is a Float with the same value as flt. Contrast this with Float#==, which performs type conversions.

1.0.eql?(1)   #=> false

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_eql(VALUE x, VALUE y)
{
if (TYPE(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;
}

#quo(numeric) ⇒ Float

Returns float / numeric.

Returns:




# File 'numeric.c'

static VALUE
flo_quo(VALUE x, VALUE y)
{
    return rb_funcall(x, '/', 1, y);
}

#finite? ⇒ Boolean

Returns true if flt is a valid IEEE floating point number (it is not infinite, and nan? is false).

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_is_finite_p(VALUE num)
{
    double value = RFLOAT_VALUE(num);

#if HAVE_FINITE
    if (!finite(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 flt.

1.2.floor      #=> 1
2.0.floor      #=> 2
(-1.2).floor   #=> -2
(-2.0).floor   #=> -2

Returns:




# File 'numeric.c'

static VALUE
flo_floor(VALUE num)
{
double f = floor(RFLOAT_VALUE(num));
long val;

if (!FIXABLE(f)) {
return rb_dbl2big(f);
}

#hash ⇒ Integer

Returns a hash code for this float.

Returns:




# File 'numeric.c'

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, ...

Returns nil, -1, or 1 depending on whether flt is finite, -infinity, or infinity.

(0.0).infinite?        #=> nil
(-1.0/0.0).infinite?   #=> -1
(+1.0/0.0).infinite?   #=> 1

Returns:

  • (nil, -1, +1) 



# File 'numeric.c'

static VALUE
flo_is_infinite_p(VALUE num)
{
double value = RFLOAT_VALUE(num);

if (isinf(value)) {
return INT2FIX( value < 0 ? -1 : 1 );
}

#abs ⇒ Float #magnitude ⇒ Float

Returns the absolute value of flt.

(-34.56).abs   #=> 34.56
-34.56.abs     #=> 34.56

Overloads:




# File 'numeric.c'

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 flt by other.

6543.21.modulo(137)      #=> 104.21
6543.21.modulo(137.24)   #=> 92.9299999999996

Overloads:




# File 'numeric.c'

static VALUE
flo_mod(VALUE x, VALUE y)
{
double fy;

switch (TYPE(y)) {
  case T_FIXNUM:
fy = (double)FIX2LONG(y);
break;
  case T_BIGNUM:
fy = rb_big2dbl(y);
break;
  case T_FLOAT:
fy = RFLOAT_VALUE(y);
break;
  default:
return rb_num_coerce_bin(x, y, '%');
}

#nan? ⇒ Boolean

Returns true if flt is an invalid IEEE floating point number.

a = -1.0      #=> -1.0
a.nan?        #=> false
a = 0.0/0.0   #=> NaN
a.nan?        #=> true

Returns:

  • (Boolean) 



# File 'numeric.c'

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.

For example:

n = 0.3.numerator    #=> 5404319552844595
d = 0.3.denominator  #=> 18014398509481984
n.fdiv(d)            #=> 0.3

Returns:




# File 'rational.c'

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.

Overloads:




# File 'complex.c'

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);
}

#quo(numeric) ⇒ Float

Returns float / numeric.

Returns:




# File 'numeric.c'

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 eps is not given, it will be chosen automatically.

For example:

0.3.rationalize          #=> (3/10)
1.333.rationalize        #=> (1333/1000)
1.333.rationalize(0.01)  #=> (4/3)




# File 'rational.c'

static VALUE
float_rationalize(int argc, VALUE *argv, VALUE self)
{
VALUE e, a, b, p, q;

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) {
e = f_abs(e);
a = f_sub(self, e);
b = f_add(self, e);
}

#round([ndigits]) ⇒ Integer, Float

Rounds flt 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

Returns:




# File 'numeric.c'

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}

#to_f ⇒ Float

As flt is already a float, returns self.

Returns:




# File 'numeric.c'

static VALUE
flo_to_f(VALUE num)
{
    return num;
}

#to_i ⇒ Integer #to_int ⇒ Integer #truncate ⇒ Integer

Returns flt truncated to an Integer.

Overloads:




# File 'numeric.c'

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);
}

#to_i ⇒ Integer #to_int ⇒ Integer #truncate ⇒ Integer

Returns flt truncated to an Integer.

Overloads:




# File 'numeric.c'

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);
}

#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.

For example:

2.0.to_r    #=> (2/1)
2.5.to_r    #=> (5/2)
-0.75.to_r  #=> (-3/4)
0.0.to_r    #=> (0/1)




# File 'rational.c'

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)));
}

#to_s ⇒ String

Returns a string containing a representation of self. As well as a fixed or exponential form of the number, the call may return "NaN", "Infinity", and "-Infinity".

Returns:




# File 'numeric.c'

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}

#to_i ⇒ Integer #to_int ⇒ Integer #truncate ⇒ Integer

Returns flt truncated to an Integer.

Overloads:




# File 'numeric.c'

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);
}

#zero? ⇒ Boolean

Returns true if flt is 0.0.

Returns:

  • (Boolean) 



# File 'numeric.c'

static VALUE
flo_zero_p(VALUE num)
{
if (RFLOAT_VALUE(num) == 0.0) {
return Qtrue;
}