Add Matrix.rows

packages/simulator/src/matrix.ts

@@ -22,14 +22,26 @@ export class Matrix {
   public buffer: Float64Array
 
   /**
-   * Return a column vector.
-   *
-   * @param elements - The elements of the vector
-   * @returns A column vector (Matrix with 1 column)
+   * Creates a new Matrix object from the given rows.
    */
-  static col(...elements: Array<number | Complex>): Matrix {
-    const res = Matrix.build(elements.length, 1, row => elements[row])
-    return res._unsafeUnwrap()
+  static rows(rows: Array<Array<number | Complex>>): Result<Matrix, Error> {
+    const height = rows.length
+    if (height === 0) {
+      return err(Error('rows is empty'))
+    }
+    const width = rows[0].length
+    if (rows[0].length === 0) {
+      return err(Error('rows[0] is empty'))
+    }
+
+    return Matrix.build(height, width, (row, col) => rows[row][col])
+  }
+
+  /**
+   * Creates a column vector from the given elements.
+   */
+  static column_vector(...elements: Array<number | Complex>): Result<Matrix, Error> {
+    return Matrix.build(elements.length, 1, row => elements[row])
   }
 
   /**

packages/simulator/src/state-vector.ts

@@ -96,32 +96,32 @@ export class StateVector {
       switch (char) {
         case '0': {
           if (paren) throw invalidBitStringError
-          kets.push(Matrix.col(1, 0))
+          kets.push(Matrix.column_vector(1, 0)._unsafeUnwrap())
           break
         }
         case '1': {
           if (paren) throw invalidBitStringError
-          kets.push(Matrix.col(0, 1))
+          kets.push(Matrix.column_vector(0, 1)._unsafeUnwrap())
           break
         }
         case '+': {
           if (paren) throw invalidBitStringError
-          kets.push(Matrix.col(1, 1).mult(Math.sqrt(0.5))._unsafeUnwrap())
+          kets.push(Matrix.column_vector(1, 1)._unsafeUnwrap().mult(Math.sqrt(0.5))._unsafeUnwrap())
           break
         }
         case '-': {
           if (paren) {
             parenToken += '-'
           } else {
-            kets.push(Matrix.col(1, -1).mult(Math.sqrt(0.5))._unsafeUnwrap())
+            kets.push(Matrix.column_vector(1, -1)._unsafeUnwrap().mult(Math.sqrt(0.5))._unsafeUnwrap())
           }
           break
         }
         case 'i': {
           if (paren) {
             parenToken += 'i'
           } else {
-            kets.push(Matrix.col(1, new Complex(0, 1)).mult(Math.sqrt(0.5))._unsafeUnwrap())
+            kets.push(Matrix.column_vector(1, new Complex(0, 1))._unsafeUnwrap().mult(Math.sqrt(0.5))._unsafeUnwrap())
           }
           break
         }
@@ -134,7 +134,7 @@ export class StateVector {
         case ')': {
           if (!paren) throw invalidBitStringError
           if (parenToken !== '-i') throw invalidBitStringError
-          kets.push(Matrix.col(1, new Complex(0, -1)).mult(Math.sqrt(0.5))._unsafeUnwrap())
+          kets.push(Matrix.column_vector(1, new Complex(0, -1))._unsafeUnwrap().mult(Math.sqrt(0.5))._unsafeUnwrap())
           paren = false
           break
         }
@@ -181,7 +181,10 @@ export class StateVector {
           .times(this.matrix.element(0, bra)._unsafeUnwrap().conjugate())
         if (amp.isEqualTo(0)) continue
 
-        const ketMat = removeBits(ket, traceBits) === 0 ? Matrix.col(1, 0) : Matrix.col(0, 1)
+        const ketMat =
+          removeBits(ket, traceBits) === 0
+            ? Matrix.column_vector(1, 0)._unsafeUnwrap()
+            : Matrix.column_vector(0, 1)._unsafeUnwrap()
         const braMat = removeBits(bra, traceBits) === 0 ? Matrix.row(1, 0) : Matrix.row(0, 1)
         const ketBra = ketMat.mult(braMat)._unsafeUnwrap()