Array
of platforms this RubyGems supports.
Computes the arc tangent given y
and x
. Returns a Float
in the range -PI..PI. Return value is a angle in radians between the positive x-axis of cartesian plane and the point given by the coordinates (x
, y
) on it.
Domain: (-INFINITY, INFINITY)
Codomain: [-PI, PI]
Math.atan2(-0.0, -1.0) #=> -3.141592653589793 Math.atan2(-1.0, -1.0) #=> -2.356194490192345 Math.atan2(-1.0, 0.0) #=> -1.5707963267948966 Math.atan2(-1.0, 1.0) #=> -0.7853981633974483 Math.atan2(-0.0, 1.0) #=> -0.0 Math.atan2(0.0, 1.0) #=> 0.0 Math.atan2(1.0, 1.0) #=> 0.7853981633974483 Math.atan2(1.0, 0.0) #=> 1.5707963267948966 Math.atan2(1.0, -1.0) #=> 2.356194490192345 Math.atan2(0.0, -1.0) #=> 3.141592653589793 Math.atan2(INFINITY, INFINITY) #=> 0.7853981633974483 Math.atan2(INFINITY, -INFINITY) #=> 2.356194490192345 Math.atan2(-INFINITY, INFINITY) #=> -0.7853981633974483 Math.atan2(-INFINITY, -INFINITY) #=> -2.356194490192345
Computes the arc tangent of x
. Returns -PI/2..PI/2.
Domain: (-INFINITY, INFINITY)
Codomain: (-PI/2, PI/2)
Math.atan(0) #=> 0.0
Computes the inverse hyperbolic tangent of x
.
Domain: (-1, 1)
Codomain: (-INFINITY, INFINITY)
Math.atanh(1) #=> Infinity
Calculates the gamma function of x.
Note that gamma(n) is same as fact(n-1) for integer n > 0. However gamma(n) returns float and can be an approximation.
def fact(n) (1..n).inject(1) {|r,i| r*i } end 1.upto(26) {|i| p [i, Math.gamma(i), fact(i-1)] } #=> [1, 1.0, 1] # [2, 1.0, 1] # [3, 2.0, 2] # [4, 6.0, 6] # [5, 24.0, 24] # [6, 120.0, 120] # [7, 720.0, 720] # [8, 5040.0, 5040] # [9, 40320.0, 40320] # [10, 362880.0, 362880] # [11, 3628800.0, 3628800] # [12, 39916800.0, 39916800] # [13, 479001600.0, 479001600] # [14, 6227020800.0, 6227020800] # [15, 87178291200.0, 87178291200] # [16, 1307674368000.0, 1307674368000] # [17, 20922789888000.0, 20922789888000] # [18, 355687428096000.0, 355687428096000] # [19, 6.402373705728e+15, 6402373705728000] # [20, 1.21645100408832e+17, 121645100408832000] # [21, 2.43290200817664e+18, 2432902008176640000] # [22, 5.109094217170944e+19, 51090942171709440000] # [23, 1.1240007277776077e+21, 1124000727777607680000] # [24, 2.5852016738885062e+22, 25852016738884976640000] # [25, 6.204484017332391e+23, 620448401733239439360000] # [26, 1.5511210043330954e+25, 15511210043330985984000000]
Calculates the logarithmic gamma of x
and the sign of gamma of x
.
Math.lgamma(x)
is same as
[Math.log(Math.gamma(x).abs), Math.gamma(x) < 0 ? -1 : 1]
but avoid overflow by Math.gamma(x)
for large x.
Math.lgamma(0) #=> [Infinity, 1]
Some operating systems retain the status of terminated child processes until the parent collects that status (normally using some variant of wait()
). If the parent never collects this status, the child stays around as a zombie process. Process::detach
prevents this by setting up a separate Ruby thread whose sole job is to reap the status of the process pid when it terminates. Use detach only when you do not intend to explicitly wait for the child to terminate.
The waiting thread returns the exit status of the detached process when it terminates, so you can use Thread#join
to know the result. If specified pid is not a valid child process ID, the thread returns nil
immediately.
The waiting thread has pid method which returns the pid.
In this first example, we don’t reap the first child process, so it appears as a zombie in the process status display.
p1 = fork { sleep 0.1 } p2 = fork { sleep 0.2 } Process.waitpid(p2) sleep 2 system("ps -ho pid,state -p #{p1}")
produces:
27389 Z
In the next example, Process::detach
is used to reap the child automatically.
p1 = fork { sleep 0.1 } p2 = fork { sleep 0.2 } Process.detach(p1) Process.waitpid(p2) sleep 2 system("ps -ho pid,state -p #{p1}")
(produces no output)
Returns the maximum number of gids allowed in the supplemental group access list.
Process.maxgroups #=> 32
Sets the maximum number of gids allowed in the supplemental group access list.
Enumerates the outdated local gems yielding the local specification and the latest remote version.
This method may take some time to return as it must check each local gem against the server’s index.
Returns a Hash
containing the following keys:
Number of started SSL/TLS handshakes in server mode
Number of established SSL/TLS sessions in server mode
Number of start renegotiations in server mode
Number of sessions that were removed due to cache overflow
Number of successfully reused connections
Number of sessions proposed by clients that were not found in the cache
Number of sessions in the internal session cache
Number of sessions retrieved from the external cache in server mode
Number of started SSL/TLS handshakes in client mode
Number of established SSL/TLS sessions in client mode
Number of start renegotiations in client mode
Number of sessions proposed by clients that were found in the cache but had expired due to timeouts
Returns true
if key is the corresponding private key to the Subject Public Key Information, false
otherwise.
Takes the first digit of the reply code to determine the status type
Like Enumerable#map
, but chains operation to be lazy-evaluated.
(1..Float::INFINITY).lazy.map {|i| i**2 } #=> #<Enumerator::Lazy: #<Enumerator::Lazy: 1..Infinity>:map> (1..Float::INFINITY).lazy.map {|i| i**2 }.first(3) #=> [1, 4, 9]
Like Enumerable#chunk
, but chains operation to be lazy-evaluated.
Iterates over the elements of the first enumerable by calling the “each” method on it with the given arguments, then proceeds to the following enumerables in sequence until all of the enumerables are exhausted.
If no block is given, returns an enumerator.
Update the digest using given string and return self
.
Update the digest using a given string and return self.