# Extension:BCmath/Glossary/zh

**Glossary for BCmath** is a list of core terms and concepts for bcmath, or arbitrary-precision arithmetic.

## Terms and concepts

- Arbitrary precision
- When calculations are not limited by specific register sizes it is referred to as arbitrary precision.

- Infinity (∞)
- Infinite numbers are valid numbers that are represented with a particular Unicode symbol, the infinity (U+221E) codepoint.
- An infinite number can have a sign, both a plus infinity (+∞) and a minus infinity (-∞).

- NaN (nan)
- Not-a-Number is the value of a calculation that has no valid representation as a number. It is called
`nan`

internally. - A NaN can have a payload that further clarify what it is or represents.

- Operation
- Numbers are combined they are said to be operands to an operation.
- Operations and operands can have their own names, like addition has addend and augend.

- Payload
- When calculations generates a NaN, then additional information might be added to the payload.
- Payloads might be inspected in the console, but will otherwise be silently forgotten.

- Scale (scale)
- The scale is how the number is shifted to process it efficiently. It is given as the argument
`scale`

to most operations. - The BCmath extension tries to estimate the scale factor if it is missing.

- Self (self)
- The actual instance, the “self”, in this case holding a number. It is called
`self`

internally.

## Operations

- add
- Add the addend to augend.

- sub
- Subtract the subtrahend from minuend.

- mul
- Multiply the multiplicator with multiplier.

- div
- Divide the divisor from dividend

- mod
- Modulus the divisor from dividend.

- pow
- Power the base to exponent.

- powmod
- Power the base to exponent and then modulus divisor.

- sqrt
- Square root of the operand.

- eq
- Is left side equal to right side.

- lt
- Is left side less than right side.

- le
- Is left side less than or equal to right side.

- {{anchor|gt|greater-than} gt
- Is left side greater than right side.

- ge
- Is left side greater than or equal to right side.

## 外部链接

- UTS #35: Unicode LDML: Numbers. (Unicode) Accessed September 21, 2019.
- Number Patterns - CLDR - Unicode Common Locale Data Repository. Accessed September 21, 2019.
- Number Symbols - CLDR - Unicode Common Locale Data Repository. Accessed September 22, 2019.
- CLDR Releases/Downloads - CLDR - Unicode Common Locale Data Repository. Accessed September 22, 2019.
- PHP: BCMath Arbitrary Precision Mathematics