mirror of https://github.com/golang/go.git
84 lines
2.0 KiB
Plaintext
84 lines
2.0 KiB
Plaintext
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package linalg
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import "math"
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// Numeric is type bound that matches any numeric type.
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// It would likely be in a constraints package in the standard library.
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type Numeric interface {
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type int, int8, int16, int32, int64,
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uint, uint8, uint16, uint32, uint64, uintptr,
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float32, float64,
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complex64, complex128
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}
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func DotProduct[T Numeric](s1, s2 []T) T {
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if len(s1) != len(s2) {
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panic("DotProduct: slices of unequal length")
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}
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var r T
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for i := range s1 {
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r += s1[i] * s2[i]
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}
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return r
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}
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// NumericAbs matches numeric types with an Abs method.
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type NumericAbs[T any] interface {
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Numeric
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Abs() T
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}
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// AbsDifference computes the absolute value of the difference of
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// a and b, where the absolute value is determined by the Abs method.
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func AbsDifference[T NumericAbs[T]](a, b T) T {
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d := a - b
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return d.Abs()
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}
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// OrderedNumeric is a type bound that matches numeric types that support the < operator.
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type OrderedNumeric interface {
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type int, int8, int16, int32, int64,
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uint, uint8, uint16, uint32, uint64, uintptr,
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float32, float64
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}
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// Complex is a type bound that matches the two complex types, which do not have a < operator.
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type Complex interface {
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type complex64, complex128
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}
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// OrderedAbs is a helper type that defines an Abs method for
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// ordered numeric types.
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type OrderedAbs[T OrderedNumeric] T
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func (a OrderedAbs[T]) Abs() OrderedAbs[T] {
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if a < 0 {
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return -a
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}
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return a
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}
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// ComplexAbs is a helper type that defines an Abs method for
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// complex types.
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type ComplexAbs[T Complex] T
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func (a ComplexAbs[T]) Abs() ComplexAbs[T] {
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r := float64(real(a))
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i := float64(imag(a))
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d := math.Sqrt(r * r + i * i)
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return ComplexAbs[T](complex(d, 0))
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}
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func OrderedAbsDifference[T OrderedNumeric](a, b T) T {
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return T(AbsDifference(OrderedAbs[T](a), OrderedAbs[T](b)))
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}
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func ComplexAbsDifference[T Complex](a, b T) T {
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return T(AbsDifference(ComplexAbs[T](a), ComplexAbs[T](b)))
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}
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