summaryrefslogtreecommitdiffstats
path: root/src/math/big/doc.go
diff options
context:
space:
mode:
authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:23:18 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:23:18 +0000
commit43a123c1ae6613b3efeed291fa552ecd909d3acf (patch)
treefd92518b7024bc74031f78a1cf9e454b65e73665 /src/math/big/doc.go
parentInitial commit. (diff)
downloadgolang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.tar.xz
golang-1.20-43a123c1ae6613b3efeed291fa552ecd909d3acf.zip
Adding upstream version 1.20.14.upstream/1.20.14upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/math/big/doc.go')
-rw-r--r--src/math/big/doc.go99
1 files changed, 99 insertions, 0 deletions
diff --git a/src/math/big/doc.go b/src/math/big/doc.go
new file mode 100644
index 0000000..65ed019
--- /dev/null
+++ b/src/math/big/doc.go
@@ -0,0 +1,99 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package big implements arbitrary-precision arithmetic (big numbers).
+The following numeric types are supported:
+
+ Int signed integers
+ Rat rational numbers
+ Float floating-point numbers
+
+The zero value for an Int, Rat, or Float correspond to 0. Thus, new
+values can be declared in the usual ways and denote 0 without further
+initialization:
+
+ var x Int // &x is an *Int of value 0
+ var r = &Rat{} // r is a *Rat of value 0
+ y := new(Float) // y is a *Float of value 0
+
+Alternatively, new values can be allocated and initialized with factory
+functions of the form:
+
+ func NewT(v V) *T
+
+For instance, NewInt(x) returns an *Int set to the value of the int64
+argument x, NewRat(a, b) returns a *Rat set to the fraction a/b where
+a and b are int64 values, and NewFloat(f) returns a *Float initialized
+to the float64 argument f. More flexibility is provided with explicit
+setters, for instance:
+
+ var z1 Int
+ z1.SetUint64(123) // z1 := 123
+ z2 := new(Rat).SetFloat64(1.25) // z2 := 5/4
+ z3 := new(Float).SetInt(z1) // z3 := 123.0
+
+Setters, numeric operations and predicates are represented as methods of
+the form:
+
+ func (z *T) SetV(v V) *T // z = v
+ func (z *T) Unary(x *T) *T // z = unary x
+ func (z *T) Binary(x, y *T) *T // z = x binary y
+ func (x *T) Pred() P // p = pred(x)
+
+with T one of Int, Rat, or Float. For unary and binary operations, the
+result is the receiver (usually named z in that case; see below); if it
+is one of the operands x or y it may be safely overwritten (and its memory
+reused).
+
+Arithmetic expressions are typically written as a sequence of individual
+method calls, with each call corresponding to an operation. The receiver
+denotes the result and the method arguments are the operation's operands.
+For instance, given three *Int values a, b and c, the invocation
+
+ c.Add(a, b)
+
+computes the sum a + b and stores the result in c, overwriting whatever
+value was held in c before. Unless specified otherwise, operations permit
+aliasing of parameters, so it is perfectly ok to write
+
+ sum.Add(sum, x)
+
+to accumulate values x in a sum.
+
+(By always passing in a result value via the receiver, memory use can be
+much better controlled. Instead of having to allocate new memory for each
+result, an operation can reuse the space allocated for the result value,
+and overwrite that value with the new result in the process.)
+
+Notational convention: Incoming method parameters (including the receiver)
+are named consistently in the API to clarify their use. Incoming operands
+are usually named x, y, a, b, and so on, but never z. A parameter specifying
+the result is named z (typically the receiver).
+
+For instance, the arguments for (*Int).Add are named x and y, and because
+the receiver specifies the result destination, it is called z:
+
+ func (z *Int) Add(x, y *Int) *Int
+
+Methods of this form typically return the incoming receiver as well, to
+enable simple call chaining.
+
+Methods which don't require a result value to be passed in (for instance,
+Int.Sign), simply return the result. In this case, the receiver is typically
+the first operand, named x:
+
+ func (x *Int) Sign() int
+
+Various methods support conversions between strings and corresponding
+numeric values, and vice versa: *Int, *Rat, and *Float values implement
+the Stringer interface for a (default) string representation of the value,
+but also provide SetString methods to initialize a value from a string in
+a variety of supported formats (see the respective SetString documentation).
+
+Finally, *Int, *Rat, and *Float satisfy the fmt package's Scanner interface
+for scanning and (except for *Rat) the Formatter interface for formatted
+printing.
+*/
+package big