# log

## Category
Math

## Arity
**Unary** — `log <number>`.

```
log <number>
```

## Description
Returns the **natural logarithm** (base e) of a number. Input is **clamped to ε** (machine epsilon, ~2.22e-16) as a minimum — zero or negative inputs return a very large negative number instead of throwing. Auto-unwraps `shared` values.

## How It Works
Calls `Math.Log(max(epsilon, x))`. The clamping prevents errors from zero/negative inputs. This matches the safety-oriented behavior of the SQ# math library.

## Usage

```sqf
log 1;                         // 0
log 2.71828;                   // ~1
log 10;                        // 2.302...

// Decay constant
_k = log 2 / _halfLife;

// Log-scale comparison
if (log _a > log _b) then { ... };  // same as a > b for positive

// Information / entropy
_entropy = -_p * log _p;
```

## Thread Safety
ReadOnly — pure computation. Safe from any scheduler.

## See Also
- [exp](exp.md) — natural exponential (inverse)
- [^](pow-operator.md) — general power
- [sqrt](sqrt.md) — square root