marcin-kordas-hoc · Oct 15, 2026 · Oct 15, 2026 · Oct 23, 2026 · Oct 23, 2026 · Oct 23, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 - Added `LINEST` for simple and multiple linear regression, with optional intercept and regression statistics. The `stats` argument must be constant because result dimensions are determined before evaluation. [#1769](https://github.com/handsontable/hyperformula/pull/1769)
 - Added the `CONCAT` function, which joins text from values, ranges, and arrays, and the `VALUETOTEXT` function, which returns a value as text in a concise or a strict format. [#1816](https://github.com/handsontable/hyperformula/pull/1816)
+- Added the `MUNIT`, `MDETERM` and `MINVERSE` matrix functions: the identity matrix, the determinant and the inverse of a square matrix. [#1817](https://github.com/handsontable/hyperformula/pull/1817)
 
 ### Fixed
 

diff --git a/docs/guide/known-limitations.md b/docs/guide/known-limitations.md
@@ -44,7 +44,7 @@ a circular reference.
 * For certain inputs, the RATE function might have no solutions, or have multiple solutions. Our implementation uses an iterative algorithm (Newton's method) to find an approximation for one of the solutions to within 1e-7. If the approximation is not found after 50 iterations, the RATE function returns the `#NUM!` error.
 * The INDEX function doesn't support returning whole rows or columns of the source range – it always returns the contents of a single cell.
 * The FILTER function accepts either single rows of equal width or single columns of equal height. In other words, all arrays passed to the FILTER function must have equal dimensions, and at least one of those dimensions must be 1.
-* Array-producing functions (e.g., SEQUENCE, FILTER) require their output dimensions to be determinable at parse time. Passing cell references or formulas as dimension arguments (e.g., `=SEQUENCE(A1)`) results in a `#VALUE!` error, because the output size cannot be resolved before evaluation.
+* Array-producing functions (e.g., SEQUENCE, MUNIT, FILTER) require their output dimensions to be determinable at parse time. Passing cell references or formulas as dimension arguments (e.g., `=SEQUENCE(A1)`) results in a `#VALUE!` error, because the output size cannot be resolved before evaluation.
 * The TEXT function does not accept embedded double-quote literals in the format string. In Excel, `""` inside a format string is an escape sequence for a literal `"` character — e.g. `=TEXT(1234.5, "#,##0.00 ""zł""")` returns `"1,234.50 zł"`. If your application requires this escape sequence, supply a custom [`stringifyCurrency`](currency-handling.md) callback.
 
 ### UNIQUE function

diff --git a/docs/guide/list-of-differences.md b/docs/guide/list-of-differences.md
@@ -117,6 +117,7 @@ To remove the differences, create [custom implementations](custom-functions.md)
 | ISODD         | =ISODD(3.5)                                                    |        FALSE |          TRUE |            TRUE |
 | CEILING.MATH  | =CEILING.MATH(-4.3, 2, 2)                                      |           -4 |            -6 |              -6 |
 | FLOOR.MATH    | =FLOOR.MATH(-4.7, 2, 2)                                        |           -6 |            -4 |              -4 |
+| MUNIT         | =ROWS(MUNIT(A1:A2))<br>where A1:A2: 3, 2                       |        VALUE |   Not checked |               2 |
 
 A few of the rows above share a root cause worth stating once:
 

diff --git a/hyperformula/src/error-message.ts b/hyperformula/src/error-message.ts
@@ -15,6 +15,8 @@ export class ErrorMessage {
   public static EmptyArray = 'Empty array not allowed.'
   public static ArrayDimensions = 'Array dimensions are not compatible.'
   public static PoolDimensions = 'Range dimensions are not compatible with the window size and the stride.'
+  public static SingularMatrix = 'Matrix is singular.'
+  public static SquareMatrix = 'Matrix must be square.'
   public static NoSpaceForArrayResult = 'No space for array result.'
   public static ValueSmall = 'Value too small.'
   public static ValueLarge = 'Value too large.'

diff --git a/hyperformula/src/i18n/languages/csCZ.ts b/hyperformula/src/i18n/languages/csCZ.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MINIFS',
     MINUTE: 'MINUTA',
     MIRR: 'MOD.MÍRA.VÝNOSNOSTI',
+    MDETERM: 'DETERMINANT',
+    MINVERSE: 'INVERZE',
     MMULT: 'SOUČIN.MATIC',
+    MUNIT: 'MUNIT',
     MOD: 'MOD',
     MONTH: 'MĚSÍC',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/daDK.ts b/hyperformula/src/i18n/languages/daDK.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MINHVISER',
     MINUTE: 'MINUT',
     MIRR: 'MIA',
+    MDETERM: 'MDETERM',
+    MINVERSE: 'MINVERT',
     MMULT: 'MPRODUKT',
+    MUNIT: 'MENHED',
     MOD: 'REST',
     MONTH: 'MÅNED',
     N: 'TAL',

diff --git a/hyperformula/src/i18n/languages/deDE.ts b/hyperformula/src/i18n/languages/deDE.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MINWENNS',
     MINUTE: 'MINUTE',
     MIRR: 'QIKV',
+    MDETERM: 'MDET',
+    MINVERSE: 'MINV',
     MMULT: 'MMULT',
+    MUNIT: 'MEINHEIT',
     MOD: 'REST',
     MONTH: 'MONAT',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/enGB.ts b/hyperformula/src/i18n/languages/enGB.ts
@@ -163,7 +163,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MINIFS',
     MINUTE: 'MINUTE',
     MIRR: 'MIRR',
+    MDETERM: 'MDETERM',
+    MINVERSE: 'MINVERSE',
     MMULT: 'MMULT',
+    MUNIT: 'MUNIT',
     MOD: 'MOD',
     MONTH: 'MONTH',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/esES.ts b/hyperformula/src/i18n/languages/esES.ts
@@ -162,7 +162,10 @@ export const dictionary: RawTranslationPackage = {
     MINIFS: 'MIN.SI.CONJUNTO',
     MINUTE: 'MINUTO',
     MIRR: 'TIRM',
+    MDETERM: 'MDETERM',
+    MINVERSE: 'MINVERSA',
     MMULT: 'MMULT',
+    MUNIT: 'M.UNIDAD',
     MOD: 'RESIDUO',
     MONTH: 'MES',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/fiFI.ts b/hyperformula/src/i18n/languages/fiFI.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MIN.JOS',
     MINUTE: 'MINUUTIT',
     MIRR: 'MSISÄINEN',
+    MDETERM: 'MDETERM',
+    MINVERSE: 'MKÄÄNTEINEN',
     MMULT: 'MKERRO',
+    MUNIT: 'YKSIKKÖM',
     MOD: 'JAKOJ',
     MONTH: 'KUUKAUSI',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/frFR.ts b/hyperformula/src/i18n/languages/frFR.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MIN.SI',
     MINUTE: 'MINUTE',
     MIRR: 'TRIM',
+    MDETERM: 'DETERMAT',
+    MINVERSE: 'INVERSEMAT',
     MMULT: 'PRODUITMAT',
+    MUNIT: 'MATRICE.UNITAIRE',
     MOD: 'MOD',
     MONTH: 'MOIS',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/huHU.ts b/hyperformula/src/i18n/languages/huHU.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MINHA',
     MINUTE: 'PERCEK',
     MIRR: 'MEGTÉRÜLÉS',
+    MDETERM: 'MDETERM',
+    MINVERSE: 'INVERZ.MÁTRIX',
     MMULT: 'MSZORZAT',
+    MUNIT: 'MMÁTRIX',
     MOD: 'MARADÉK',
     MONTH: 'HÓNAP',
     N: 'S',

diff --git a/hyperformula/src/i18n/languages/idID.ts b/hyperformula/src/i18n/languages/idID.ts
@@ -163,7 +163,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MIN.JIKAS',
     MINUTE: 'MENIT',
     MIRR: 'MIRR',
+    MDETERM: 'MDETERM',
+    MINVERSE: 'MINVERSE',
     MMULT: 'MMULT',
+    MUNIT: 'MUNIT',
     MOD: 'MOD',
     MONTH: 'BULAN',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/itIT.ts b/hyperformula/src/i18n/languages/itIT.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MIN.PIÙ.SE',
     MINUTE: 'MINUTO',
     MIRR: 'TIR.VAR',
+    MDETERM: 'MATR.DETERM',
+    MINVERSE: 'MATR.INVERSA',
     MMULT: 'MATR.PRODOTTO',
+    MUNIT: 'MATR.UNIT',
     MOD: 'RESTO',
     MONTH: 'MESE',
     N: 'NUM',

diff --git a/hyperformula/src/i18n/languages/nbNO.ts b/hyperformula/src/i18n/languages/nbNO.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MIN.HVIS.SETT',
     MINUTE: 'MINUTT',
     MIRR: 'MODIR',
+    MDETERM: 'MDETERM',
+    MINVERSE: 'MINVERS',
     MMULT: 'MMULT',
+    MUNIT: 'MENHET',
     MOD: 'REST',
     MONTH: 'MÅNED',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/nlNL.ts b/hyperformula/src/i18n/languages/nlNL.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MIN.ALS.VOORWAARDEN',
     MINUTE: 'MINUUT',
     MIRR: 'GIR',
+    MDETERM: 'DETERMINANTMAT',
+    MINVERSE: 'INVERSEMAT',
     MMULT: 'PRODUCTMAT',
+    MUNIT: 'EENHEIDMAT',
     MOD: 'REST',
     MONTH: 'MAAND',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/plPL.ts b/hyperformula/src/i18n/languages/plPL.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MIN.WARUNKÓW',
     MINUTE: 'MINUTA',
     MIRR: 'MIRR',
+    MDETERM: 'WYZNACZNIK.MACIERZY',
+    MINVERSE: 'MACIERZ.ODW',
     MMULT: 'MACIERZ.ILOCZYN',
+    MUNIT: 'MACIERZ.JEDNOSTKOWA',
     MOD: 'MOD',
     MONTH: 'MIESIĄC',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/ptPT.ts b/hyperformula/src/i18n/languages/ptPT.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MÍNIMOSES',
     MINUTE: 'MINUTO',
     MIRR: 'MTIR',
+    MDETERM: 'MATRIZ.DETERM',
+    MINVERSE: 'MATRIZ.INVERSA',
     MMULT: 'MATRIZ.MULT',
+    MUNIT: 'UNIDM',
     MOD: 'MOD',
     MONTH: 'MÊS',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/ruRU.ts b/hyperformula/src/i18n/languages/ruRU.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'МИНЕСЛИ',
     MINUTE: 'МИНУТЫ',
     MIRR: 'МВСД',
+    MDETERM: 'МОПРЕД',
+    MINVERSE: 'МОБР',
     MMULT: 'МУМНОЖ',
+    MUNIT: 'МЕДИН',
     MOD: 'ОСТАТ',
     MONTH: 'МЕСЯЦ',
     N: 'Ч',

diff --git a/hyperformula/src/i18n/languages/svSE.ts b/hyperformula/src/i18n/languages/svSE.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'MINIFS',
     MINUTE: 'MINUT',
     MIRR: 'MODIR',
+    MDETERM: 'MDETERM',
+    MINVERSE: 'MINVERT',
     MMULT: 'MMULT',
+    MUNIT: 'MENHET',
     MOD: 'REST',
     MONTH: 'MÅNAD',
     N: 'N',

diff --git a/hyperformula/src/i18n/languages/trTR.ts b/hyperformula/src/i18n/languages/trTR.ts
@@ -162,7 +162,10 @@ const dictionary: RawTranslationPackage = {
     MINIFS: 'ÇOKEĞERMİN',
     MINUTE: 'DAKİKA',
     MIRR: 'D_İÇ_VERİM_ORANI',
+    MDETERM: 'DETERMİNANT',
+    MINVERSE: 'DİZEY_TERS',
     MMULT: 'DÇARP',
+    MUNIT: 'BİRİMMATRİS',
     MOD: 'MOD',
     MONTH: 'AY',
     N: 'S',

diff --git a/hyperformula/src/interpreter/functionMetadata/categories/matrix-functions.ts b/hyperformula/src/interpreter/functionMetadata/categories/matrix-functions.ts
@@ -24,11 +24,32 @@ export const MATRIX_FUNCTIONS_DOCS: Record<string, FunctionDoc> = {
     documentationUrl: 'https://hyperformula.handsontable.com/docs/guide/built-in-functions.html',
     examples: ['=MEDIANPOOL(A1:D4, 2)', '=MEDIANPOOL(A1:D4, 2, 1)'],
   },
+  MDETERM: {
+    category: 'Matrix functions',
+    shortDescription: 'Calculates the determinant of a square array. A non-square array or an array with a non-numeric value returns the #VALUE! error.',
+    parameters: [{name: 'array', description: 'The square range or array of numbers whose determinant is calculated.'}],
+    documentationUrl: 'https://hyperformula.handsontable.com/docs/guide/built-in-functions.html',
+    examples: ['=MDETERM(A1:B2)', '=MDETERM({1,2;3,4})'],
+  },
+  MINVERSE: {
+    category: 'Matrix functions',
+    shortDescription: 'Calculates the inverse of a square array. A non-square array or an array with a non-numeric value returns the #VALUE! error; a singular array returns the #NUM! error.',
+    parameters: [{name: 'array', description: 'The square range or array of numbers to invert.'}],
+    documentationUrl: 'https://hyperformula.handsontable.com/docs/guide/built-in-functions.html',
+    examples: ['=MINVERSE(A1:B2)', '=MINVERSE({1,2;3,4})'],
+  },
   MMULT: {
     category: 'Matrix functions',
     shortDescription: 'Calculates the array product of two arrays.',
     parameters: [{name: 'array1', description: 'The first range of numbers in the matrix multiplication; its column count must equal the row count of array2.'}, {name: 'array2', description: 'The second range of numbers in the matrix multiplication; its row count must equal the column count of array1.'}],
     documentationUrl: 'https://hyperformula.handsontable.com/docs/guide/built-in-functions.html',
     examples: ['=MMULT(A1:B2, D1:E2)', '=MMULT(A1:C2, A4:B6)'],
   },
+  MUNIT: {
+    category: 'Matrix functions',
+    shortDescription: 'Returns the identity matrix of the given dimension. A fractional dimension is truncated; a dimension below 1 or a non-numeric one returns the #VALUE! error.',
+    parameters: [{name: 'dimension', description: 'The number of rows and columns of the returned matrix.'}],
+    documentationUrl: 'https://hyperformula.handsontable.com/docs/guide/built-in-functions.html',
+    examples: ['=MUNIT(3)', '=MMULT(A1:C3, MUNIT(3))'],
+  },
 }
diff --git a/hyperformula/src/interpreter/plugin/FunctionPlugin.ts b/hyperformula/src/interpreter/plugin/FunctionPlugin.ts
@@ -314,6 +314,23 @@ export abstract class FunctionPlugin implements FunctionPluginTypecheck<Function
 
   protected coerceScalarToNumberOrError = (arg: InternalScalarValue): ExtendedNumber | CellError => this.arithmeticHelper.coerceScalarToNumberOrError(arg)
 
+  /**
+   * Reads a number written directly in a formula, with an optional sign, such as `3`, `+3` or `-3`. A function whose
+   * result size depends on an argument uses it to predict that size before the formula is evaluated.
+   *
+   * @param node - an argument of a function call
+   * @returns the number, or undefined when the argument is anything else and its value is known only after evaluation
+   */
+  protected signedNumberLiteral(node: Ast): Maybe<number> {
+    if (node.type === AstNodeType.NUMBER) {
+      return node.value
+    }
+    if ((node.type === AstNodeType.PLUS_UNARY_OP || node.type === AstNodeType.MINUS_UNARY_OP) && node.value.type === AstNodeType.NUMBER) {
+      return node.type === AstNodeType.MINUS_UNARY_OP ? -node.value.value : node.value.value
+    }
+    return undefined
+  }
+
   protected coerceToType(arg: InterpreterValue, coercedType: FunctionArgument, state: InterpreterState): Maybe<InterpreterValue | complex | RawNoErrorScalarValue> {
     let ret
     if (arg instanceof SimpleRangeValue) {