Documentation
¶
Overview ¶
Package math provides useful math functions
SPDX-License-Identifier: Apache-2.0
Index ¶
- Variables
- func Abs[T constraint.Numeric](val *T) error
- func AddInt[T constraint.SignedInteger](ae1 T, ae2 *T) error
- func AddUint[T constraint.UnsignedInteger](ae1 T, ae2 *T) error
- func AdjustDecimalFormat(d1, d2 Decimal) (string, string)
- func AdjustDecimalScale(d1, d2 *Decimal) error
- func CmpComplex[T constraint.Complex](val1, val2 T) (res int)
- func CmpOrdered[T constraint.Ordered](val1, val2 T) (res int)
- func Div[T constraint.Numeric](dividend T, divisor T, quotient *T) error
- func DivBigOps[T constraint.BigOps[T]](dividend T, divisor T, quotient *T) error
- func MaxCmp[T constraint.Cmp[T]](val1, val2 T) T
- func MaxComplex[T constraint.Complex](val1, val2 T) T
- func MaxOrdered[T constraint.Ordered](val1, val2 T) T
- func MinCmp[T constraint.Cmp[T]](val1, val2 T) T
- func MinComplex[T constraint.Complex](val1, val2 T) T
- func MinOrdered[T constraint.Ordered](val1, val2 T) T
- func Mul[T constraint.Integer](mp T, ma *T) error
- func SubInt[T constraint.SignedInteger](me T, sed *T) error
- func SubUint[T constraint.UnsignedInteger](me T, sed *T) error
- type Decimal
- func (d Decimal) Add(o Decimal) (Decimal, error)
- func (d Decimal) Cmp(o Decimal) int
- func (d Decimal) DivIntAdd(o uint) ([]Decimal, error)
- func (d Decimal) DivIntQuoRem(o uint) (Decimal, Decimal, error)
- func (d Decimal) Mul(o Decimal) (Decimal, error)
- func (d Decimal) MustAdd(o Decimal) Decimal
- func (d Decimal) MustDivIntAdd(o uint) []Decimal
- func (d Decimal) MustDivIntQuoRem(o uint) (Decimal, Decimal)
- func (d Decimal) MustMul(o Decimal) Decimal
- func (d Decimal) MustSub(o Decimal) Decimal
- func (d Decimal) Negate() Decimal
- func (d Decimal) Precision() int
- func (d Decimal) Scale() uint
- func (d Decimal) Sign() (sgn int)
- func (d Decimal) String() (str string)
- func (d Decimal) Sub(o Decimal) (Decimal, error)
- type Range
- type RangeMode
Constants ¶
This section is empty.
Variables ¶
var ( OverflowErr = fmt.Errorf("Overflow error") UnderflowErr = fmt.Errorf("Underflow error") DivByZeroErr = fmt.Errorf("Division by zero error") )
Constants
Functions ¶
func Abs ¶
func Abs[T constraint.Numeric](val *T) error
Abs calculates the absolute value of any numeric type. Integer types have a range of -N ... +(N-1), which means that if you try to calculate abs(-N), the result is -N. The reason for this is that there is no corresponding +N, that would require more bits. In this special case, an error is returned, otherwise nil is returned. Note that while the constraint allows unsigned ints for completeness, no operation is performed.
func AddInt ¶
func AddInt[T constraint.SignedInteger](ae1 T, ae2 *T) error
AddInt adds two signed integers overwriting the second value, and returns an error if over/underflow occurs. Over/underflow occurrs if two numbers of the same sign are added, and the sign of result has changed. EG, two positive ints are added to create a result too large to be represented in the same number of bits,
or two negative ints are added to create a result too small to be represented in the same number of bits.
func AddUint ¶
func AddUint[T constraint.UnsignedInteger](ae1 T, ae2 *T) error
AddUint adds two unsigned integers overwriting the second value, and returns an error if overflow occurs. Overflow occurs if two numbers are added, and the magnitude of result is smaller.
func AdjustDecimalFormat ¶
AdjustDecimalFormat adjusts the two decimals strings to have the same number of digits before and the decimal, and the same number of digits after the decimal. Leading and trailing zeros are added as needed. Since minus has a higher ASCII value than plus, a positive number has a leading slash.
The strings returned are almost comparable: "-2" > "-1".
Examples: 30, 5 -> " 30", " 05" 1.23, -78.295 -> " 01.230", "-78.295"
func AdjustDecimalScale ¶
AdjustDecimalScale adjusts the scale of d1 and d2:
- If both numbers have the same scale, no adjustment is made
- Otherwise, the number with the smaller scale is usually adjusted to the same scale as the other number
- Increasing the scale can cause some most significant digits to be lost, in which case the other number is rounded down to match the scale
Examples:
1.5 and 1.25 -> 1.50 and 1.25 1.5 and 18 digits with no decimals -> 18 digits cannot increase scale, so round 1.5 to 2 99_999_999_999_999_999.5 and 1 -> the 18 digits round to a 19 digit value, an error occurs
func CmpComplex ¶
func CmpComplex[T constraint.Complex](val1, val2 T) (res int)
CmpComplex compares two complex types and returns -1, 0, 1, depending on whether val1 is <, =, or > val2.
func CmpOrdered ¶
func CmpOrdered[T constraint.Ordered](val1, val2 T) (res int)
CmpOrdered compares two ordered types and returns -1, 0, 1, depending on whether val1 is <, =, or > val2.
func Div ¶
func Div[T constraint.Numeric](dividend T, divisor T, quotient *T) error
Div calculates the quotient of a division operation of a pair of integers or a pair of floating point types. In the case of integers, the remainder is handled as follows: - If the divisor is even, and abs(remainder) >= abs(divisor) / 2, then increase magnitude of quotient by one. - If the divisor is odd, and abs(remainder) > abs(divisor) / 2, then increase magnitude of quotient by one.
Increasing the magnitude by one means add one of the quotient is positive, subtract one if negative. The purpose of adjusting the magnitude is to get the same result as rounding the floating point calculation. Floats are not used since 32 and 64 bit integer values can have a magnitude too large to be expressed accurately in a float.
Integer Examples: 18 / 4 = 4 remainder 2. Since divisor 4 is even and remainder 2 is >= (4 / 2 = 2), increment quotient to 5 (round 4.5 up). 17 / 5 = 3 remainder 2. Since divisor 5 is odd and remainder 2 is not > (5 / 2 = 2), leave quotient as is (round 3.4 down).
func DivBigOps ¶
func DivBigOps[T constraint.BigOps[T]](dividend T, divisor T, quotient *T) error
DivBigOps is the BigOps version of Div
func MaxCmp ¶
func MaxCmp[T constraint.Cmp[T]](val1, val2 T) T
MaxCmp returns the maximum value of two comparable types
func MaxComplex ¶
func MaxComplex[T constraint.Complex](val1, val2 T) T
MaxComplex returns the maximum value of two complex types
func MaxOrdered ¶
func MaxOrdered[T constraint.Ordered](val1, val2 T) T
MaxOrdered returns the maximum value of two ordered types
func MinCmp ¶
func MinCmp[T constraint.Cmp[T]](val1, val2 T) T
MinCmp returns the minimum value of two comparable types
func MinComplex ¶
func MinComplex[T constraint.Complex](val1, val2 T) T
MinComplex returns the minimum value of two complex types
func MinOrdered ¶
func MinOrdered[T constraint.Ordered](val1, val2 T) T
MinOrdered returns the minimum value of two ordered types
func Mul ¶
func Mul[T constraint.Integer](mp T, ma *T) error
Mul multiples two integers overwriting the second value, and returns an error if over/underflow occurs. Over/underflow occurs if the magnitude of the result requires more bits than the type provides. Unsigned types can only overflow.
func SubInt ¶
func SubInt[T constraint.SignedInteger](me T, sed *T) error
SubInt subtracts two integers as sed = me - sed, overwriting the second value, and returns an error if over/underflow occurs. See AddInt.
func SubUint ¶
func SubUint[T constraint.UnsignedInteger](me T, sed *T) error
SubUint subtracts two integers as sed = me - sed, overwriting the second value, and returns an error if underflow occurs. Underflow occurs if sed > me before the subtraction is performed.
Types ¶
type Decimal ¶
type Decimal struct {
// contains filtered or unexported fields
}
Decimal is like SQL Decimal(precision, scale): - precision is always 18, the maximum number of decimal digits a signed 64 bit value can store - scale is number of digits after decimal place, must be <= 18 (default 2 as most popular use is money)
The zero value is ready to use
func MustDecimal ¶
MustDecimal is a must version of OfDecimal
func OfDecimal ¶
OfDecimal creates a Decimal with the given sign, digits, and optional scale (default 0)
func StringToDecimal ¶
StringToDecimal creates a Decimal from the given string The string must contain no more than 18 significant digits (leading zeros are not allowed), and satisfy the following regex: -?[1-9][0-9]*(.[0-9]+)?
func (Decimal) Add ¶
Add adds two decimals together by first adjusting them to the same scale, then adding their values Returns an error if: - Adjusting the scale produces an error - Addition overflows or underflows
func (Decimal) Cmp ¶
Cmp compares d against o, and returns -1, 0, or 1 depending on whether d < o, d = o, or d > o, respectively.
func (Decimal) DivIntAdd ¶
DintIntAdd is like DivIntQuoRem, except that it returns a slice of values that add up to d. EG, 100.00 / 3 = [33.34, 33.33, 33.33]. This method just calls DivIntQuoRem and spreads the remainder across the first remainder values returned.
func (Decimal) DivIntQuoRem ¶
DivIntQuoRem divides d by unsigned integer o, and returns (quotient, remainder, error). The scale of the quotient and remainder are the same as that of d. EG, 100.00 / 3 = 33.33 remainder 0.01.
The divisor o cannot be larger than the dividend d.
Returns a division by zero error if o is zero. Returns a divisor too large error if the o > d.value.
func (Decimal) Mul ¶
Mul multiplies d by o, then sets the result scale to (d scale) + (o scale) Returns an overflow error if the result > 18 9 digits.
func (Decimal) MustDivIntAdd ¶
MustDivIntAdd is a must version of DivIntAdd
func (Decimal) MustDivIntQuoRem ¶
MustDivIntQuoRem is a must version of DivIntQuoRem
func (Decimal) Precision ¶
Precison returns the total number of digits of a decimal, including trailing zeros. Effectively, the length of the decimal as a string, without a minus sign or decimal point.
type Range ¶
type Range[T constraint.IntegerAndFloat] struct { // contains filtered or unexported fields }
Range represents a range of values. The range may be open, half open, or closed.
func OfRange ¶
func OfRange[T constraint.IntegerAndFloat]( min T, minMode RangeMode, max T, maxMode RangeMode, initial T, ) Range[T]
OfRange constructs a range from minimum value and mode, maximum value and mode, and initial value. An initial value is required since min and max could both be open and the type could a float, so there is no sensible default initial value.
Panics if the initial value is not in the specified range.
Source Files