# Function setMultiplicity Count the multiplicity of an element in a multiset. A multi-dimension array will be converted to a single-dimension array before the operation. ## Syntax ```js math.setMultiplicity(element, set) ``` ### Parameters Parameter | Type | Description --------- | ---- | ----------- `e` | number | BigNumber | Fraction | Complex | An element in the multiset `a` | Array | Matrix | A multiset ### Returns Type | Description ---- | ----------- number | The number of how many times the multiset contains the element ### Throws Type | Description ---- | ----------- ## Examples ```js math.setMultiplicity(1, [1, 2, 2, 4]) // returns 1 math.setMultiplicity(2, [1, 2, 2, 4]) // returns 2 ``` ## See also [setDistinct](setDistinct.md), [setSize](setSize.md)