Make index method in tensor class

lib/model/nns/layer/gru.js

@@ -45,7 +45,7 @@ export default class GRULayer extends Layer {
 		x = x.transpose(1, 0, 2)
 		this._x = []
 		for (let k = 0; k < x.sizes[0]; k++) {
-			this._x[k] = x.at(k).toMatrix()
+			this._x[k] = x.index(k).toMatrix()
 		}
 
 		const s = []
@@ -69,7 +69,7 @@ export default class GRULayer extends Layer {
 		if (this._return_sequences) {
 			bo = bo.transpose(1, 0, 2)
 			for (let i = 0; i < s; i++) {
-				this._bo[i] = bo.at(i).toMatrix()
+				this._bo[i] = bo.index(i).toMatrix()
 			}
 		} else {
 			this._bo[s - 1] = bo

lib/model/nns/layer/lstm.js

@@ -74,7 +74,7 @@ export default class LSTMLayer extends Layer {
 		x = x.transpose(1, 0, 2)
 		this._x = []
 		for (let k = 0; k < x.sizes[0]; k++) {
-			this._x[k] = x.at(k).toMatrix()
+			this._x[k] = x.index(k).toMatrix()
 		}
 		this._y = []
 
@@ -98,7 +98,7 @@ export default class LSTMLayer extends Layer {
 		if (this._return_sequences) {
 			bo = bo.transpose(1, 0, 2)
 			for (let i = 0; i < s; i++) {
-				this._bo[i] = bo.at(i).toMatrix()
+				this._bo[i] = bo.index(i).toMatrix()
 			}
 		} else {
 			this._bo[s - 1] = bo

lib/model/nns/layer/rnn.js

@@ -66,7 +66,7 @@ export default class RNNLayer extends Layer {
 		x = x.transpose(1, 0, 2)
 		this._i = []
 		for (let k = 0; k < x.sizes[0]; k++) {
-			this._i[k] = x.at(k).toMatrix()
+			this._i[k] = x.index(k).toMatrix()
 		}
 		this._o = []
 		this._z = []
@@ -97,7 +97,7 @@ export default class RNNLayer extends Layer {
 		if (this._return_sequences) {
 			bo = bo.transpose(1, 0, 2)
 			for (let i = 0; i < s; i++) {
-				this._bo[i] = bo.at(i).toMatrix()
+				this._bo[i] = bo.index(i).toMatrix()
 			}
 		} else {
 			this._bo[s - 1] = bo

lib/util/tensor.js

@@ -287,17 +287,30 @@ export default class Tensor {
 	}
 
 	/**
-	 * Returns value(s) at the index position.
+	 * Returns value at the index position.
 	 *
 	 * @param  {...number} i Index values
-	 * @returns {number | Tensor} The value or sub tensor
+	 * @returns {number} The value
 	 */
 	at(...i) {
 		if (Array.isArray(i[0])) {
 			i = i[0]
 		}
-		if (i.length === this.dimension) {
-			return this._value[this._to_position(...i)]
+		if (i.length !== this.dimension) {
+			throw new MatrixException('Length is invalid.')
+		}
+		return this._value[this._to_position(...i)]
+	}
+
+	/**
+	 * Returns tensor at the index position.
+	 *
+	 * @param  {...number} i Index values
+	 * @returns {Tensor} Sub tensor
+	 */
+	index(...i) {
+		if (Array.isArray(i[0])) {
+			i = i[0]
 		}
 
 		let s = 0

tests/lib/util/tensor.test.js

@@ -353,6 +353,51 @@ describe('Tensor', () => {
 			expect(() => ten.at([i, j, k])).toThrow('Index out of bounds.')
 		})
 
+		test.each([[0], [0, 0]])('fail[%i]', i => {
+			const ten = new Tensor([2, 3, 4])
+			expect(() => ten.at(i)).toThrow('Length is invalid.')
+			expect(() => ten.at([i])).toThrow('Length is invalid.')
+		})
+	})
+
+	describe('index', () => {
+		test('default', () => {
+			const data = [
+				[
+					[1, 2],
+					[3, 4],
+					[5, 6],
+				],
+				[
+					[7, 8],
+					[9, 10],
+					[11, 12],
+				],
+			]
+			const ten = new Tensor([2, 3, 2], data)
+			for (let i = 0; i < 2; i++) {
+				for (let j = 0; j < 3; j++) {
+					for (let k = 0; k < 2; k++) {
+						expect(ten.index(i, j, k).at()).toBe(data[i][j][k])
+						expect(ten.index([i, j, k]).at()).toBe(data[i][j][k])
+					}
+				}
+			}
+		})
+
+		test.each([
+			[-1, 0, 0],
+			[2, 0, 0],
+			[0, -1, 0],
+			[0, 3, 0],
+			[0, 0, -1],
+			[0, 0, 4],
+		])('fail[%i, %i, %i]', (i, j, k) => {
+			const ten = new Tensor([2, 3, 4])
+			expect(() => ten.index(i, j, k)).toThrow('Index out of bounds.')
+			expect(() => ten.index([i, j, k])).toThrow('Index out of bounds.')
+		})
+
 		test('multi', () => {
 			const data = [
 				[
@@ -368,16 +413,16 @@ describe('Tensor', () => {
 			]
 			const ten = new Tensor([2, 3, 2], data)
 
-			const at = ten.at(1, 1)
+			const at = ten.index(1, 1)
 			expect(at.sizes).toEqual([2])
 			expect(at.at(0)).toBe(9)
 			expect(at.at(1)).toBe(10)
 		})
 
 		test.each([[-1], [2]])('fail[%i]', i => {
 			const ten = new Tensor([2, 3, 4])
-			expect(() => ten.at(i)).toThrow('Index out of bounds.')
-			expect(() => ten.at([i])).toThrow('Index out of bounds.')
+			expect(() => ten.index(i)).toThrow('Index out of bounds.')
+			expect(() => ten.index([i])).toThrow('Index out of bounds.')
 		})
 
 		test.each([
@@ -387,8 +432,8 @@ describe('Tensor', () => {
 			[0, 3],
 		])('fail[%i, %i]', (i, j) => {
 			const ten = new Tensor([2, 3, 4])
-			expect(() => ten.at(i, j)).toThrow('Index out of bounds.')
-			expect(() => ten.at([i, j])).toThrow('Index out of bounds.')
+			expect(() => ten.index(i, j)).toThrow('Index out of bounds.')
+			expect(() => ten.index([i, j])).toThrow('Index out of bounds.')
 		})
 	})