rename Matrix#columnAt -> column

packages/simulator/src/matrix.ts

@@ -128,6 +128,28 @@ export class Matrix {
     return ok(this)
   }
 
+  /**
+   * Retrieves a column from the matrix.
+   */
+  column(colIndex: number): Result<Complex[], Error> {
+    if (colIndex < 0) {
+      return err(Error('colIndex < 0'))
+    }
+    if (colIndex > this.width) {
+      return err(Error('colIndex > this.width'))
+    }
+
+    const col = []
+    for (let row = 0; row < this.height; row++) {
+      const element = this.element(row, colIndex)
+      if (element.isErr()) {
+        return err(element.error)
+      }
+      col.push(element.value)
+    }
+    return ok(col)
+  }
+
   /**
    * Adds another matrix to the current matrix.
    */
@@ -199,27 +221,6 @@ export class Matrix {
     return Matrix.create(h, w, buf)._unsafeUnwrap()
   }
 
-  /**
-   * Returns the `colIndex` column of the matrix.
-   *
-   * @param colIndex - The column index
-   * @returns A result object with the column or an error
-   */
-  columnAt(colIndex: number): Result<Complex[], Error> {
-    if (colIndex < 0) {
-      return err(Error('colIndex < 0'))
-    }
-    if (colIndex > this.width) {
-      return err(Error('colIndex > this.width'))
-    }
-
-    const col = []
-    for (let row = 0; row < this.height; row++) {
-      col.push(this.element(row, colIndex)._unsafeUnwrap())
-    }
-    return ok(col)
-  }
-
   /**
    * Returns the matrix as an array of rows.
    *

packages/simulator/src/simulator.ts

@@ -2462,7 +2462,7 @@ export class Simulator {
   }
 
   amplitudes(): Complex[] {
-    return this.state.matrix.columnAt(0)._unsafeUnwrap()
+    return this.state.matrix.column(0)._unsafeUnwrap()
   }
 
   private u(u: Matrix, ...targets: number[]): void {

packages/simulator/test/matrix.test.ts

@@ -40,6 +40,26 @@ describe('Matrix', () => {
     expect(m._unsafeUnwrap().toString()).toBe('{{0, 10, 20}, {1, 11, 21}}')
   })
 
+  describe('column', () => {
+    const m = M([
+      [2, 3],
+      [5, 7],
+    ])
+
+    test('returns a Complex array', () => {
+      expect(equate(m.column(0)._unsafeUnwrap(), [2, 5])).toBeTruthy()
+      expect(equate(m.column(1)._unsafeUnwrap(), [3, 7])).toBeTruthy()
+    })
+
+    test('negative index error', () => {
+      expect(m.column(-1)._unsafeUnwrapErr().message).toBe('colIndex < 0')
+    })
+
+    test('index too large error', () => {
+      expect(m.column(100)._unsafeUnwrapErr().message).toBe('colIndex > this.width')
+    })
+  })
+
   describe('add', () => {
     test('add Matrix', () => {
       expect(
@@ -216,21 +236,6 @@ describe('Matrix', () => {
     })
   })
 
-  test('columnAt', () => {
-    const m = squareMatrix(2, 3, 5, 7)
-    expect(equate(m.columnAt(0)._unsafeUnwrap(), [2, 5])).toBeTruthy()
-    expect(equate(m.columnAt(1)._unsafeUnwrap(), [3, 7])).toBeTruthy()
-    expect(equate(Matrix.column_vector(1, 2, 3)._unsafeUnwrap().columnAt(0)._unsafeUnwrap(), [1, 2, 3])).toBeTruthy()
-
-    const resErrNegativeIndex = m.columnAt(-1)
-    expect(resErrNegativeIndex.isErr()).toBeTruthy()
-    expect(resErrNegativeIndex._unsafeUnwrapErr().message).toBe('colIndex < 0')
-
-    const resErrIndexTooLarge = m.columnAt(100)
-    expect(resErrIndexTooLarge.isErr()).toBeTruthy()
-    expect(resErrIndexTooLarge._unsafeUnwrapErr().message).toBe('colIndex > this.width')
-  })
-
   test('isHermitian', () => {
     const i = Complex.I