Struct TrendFn 

pub struct TrendFn;

Returns fitted y-values along a linear trend derived from known data.

TREND performs simple linear regression and returns predictions for new_x (or defaults).

Remarks

• known_y is required; known_x defaults to 1..n when omitted.
• new_x defaults to known_x when omitted.
• const defaults to TRUE; set to FALSE to force a zero intercept.
• Returns spreadsheet errors for empty data, mismatched lengths, or degenerate x-variance.

Examples

title: "Predict two future points on a line"
formula: "=TREND({2,4,6},{1,2,3},{4,5})"
expected:
  - [8, 10]

title: "Default x-values with fitted trend"
formula: "=TREND({3,5,7})"
expected:
  - [3, 5, 7]

Trait Implementations

impl Debug for TrendFn

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

Formats the value using the given formatter.

impl Function for TrendFn

[formualizer-docgen:schema:start] Name: TREND Type: TrendFn Min args: 1 Max args: variadic Variadic: true Signature: TREND(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.