Struct LogestFn 

pub struct LogestFn;

Returns parameters for an exponential model fitted to known data.

LOGEST fits y = b * m^x and returns either [m, b] or an expanded statistics matrix.

Remarks

• All known y-values must be strictly greater than 0.
• known_x defaults to 1..n when omitted.
• const controls whether b is fitted (TRUE by default).
• stats=TRUE returns a 5x2 statistics block; otherwise returns 1x2.

Examples

title: "Exponential base and intercept"
formula: "=LOGEST({2,4,8},{1,2,3})"
expected:
  - [2, 1]

title: "Alternative growth series"
formula: "=LOGEST({3,6,12},{1,2,3})"
expected:
  - [2, 1.5]

Trait Implementations

impl Debug for LogestFn

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Function for LogestFn

[formualizer-docgen:schema:start] Name: LOGEST Type: LogestFn Min args: 1 Max args: variadic Variadic: true Signature: LOGEST(arg1…: number@range) Arg schema: arg1{kinds=number,required=true,shape=range,by_ref=false,coercion=NumberLenientText,max=None,repeating=None,default=false} Caps: PURE, NUMERIC_ONLY [formualizer-docgen:schema:end]

fn caps(&self) -> FnCaps

Capability flags for this function

fn name(&self) -> &'static str

fn min_args(&self) -> usize

fn variadic(&self) -> bool

fn arg_schema(&self) -> &'static [ArgSchema]

fn eval<'a, 'b, 'c>( &self, args: &'c [ArgumentHandle<'a, 'b>], _ctx: &dyn FunctionContext<'b>, ) -> Result<CalcValue<'b>, ExcelError>

The unified evaluation path.

fn namespace(&self) -> &'static str

fn volatile(&self) -> bool

fn aliases(&self) -> &'static [&'static str]

Optional list of additional alias names (case-insensitive) that should resolve to this function. Default: empty slice. Implementors can override to expose legacy names. Returned slice must have ’static lifetime (typically a static array reference).

fn function_salt(&self) -> u64

fn eval_reference<'a, 'b, 'c>( &self, _args: &'c [ArgumentHandle<'a, 'b>], _ctx: &dyn FunctionContext<'b>, ) -> Option<Result<ReferenceType, ExcelError>>

Optional reference result path. Only called by the interpreter/engine when the callsite expects a reference (e.g., range combinators, by-ref argument positions, or spill sources).

fn dispatch<'a, 'b, 'c>( &self, args: &'c [ArgumentHandle<'a, 'b>], ctx: &dyn FunctionContext<'b>, ) -> Result<CalcValue<'b>, ExcelError>

Dispatch to the unified evaluation path with automatic argument validation.