Merge pull request #59 from gyrdym/matrix-from-columns-constructor-em…

…pty-list

Empty list-based source support for `Float32Matrix.rows` and `Float32Matrix.columns` added

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 10.0.3
+- `Float32Matrix.columns`: empty list supported as a source
+- `Float32Matrix.rows`: empty list supported as a source
+
 ## 10.0.2
 - `Float32Matrix.fromList`: empty list supported as a source
 

lib/src/common/helper/get_length_of_first_or_zero.dart

@@ -1,2 +1,2 @@
-int getLengthOfFirstOrZero(List<List<double>> collection) =>
+int getLengthOfFirstOrZero<T extends Iterable<double>>(List<T> collection) =>
     collection.isNotEmpty ? collection.first.length : 0;

lib/src/matrix/common/data_manager/data_manager_impl.dart

@@ -16,14 +16,14 @@ class DataManagerImpl implements DataManager {
       this._typedListHelper,
   ) :
         rowsNum = source.length,
-        columnsNum = getLengthOfFirstOrZero(source),
+        columnsNum = getLengthOfFirstOrZero<List<double>>(source),
         _rowsIndicesRange = ZRange.closedOpen(0, source.length),
         _colsIndicesRange = ZRange
-            .closedOpen(0, getLengthOfFirstOrZero(source)),
+            .closedOpen(0, getLengthOfFirstOrZero<List<double>>(source)),
         _rowsCache = List<Vector>(source.length),
-        _colsCache = List<Vector>(getLengthOfFirstOrZero(source)),
-        _data = ByteData(source.length * getLengthOfFirstOrZero(source) *
-            bytesPerElement) {
+        _colsCache = List<Vector>(getLengthOfFirstOrZero<List<double>>(source)),
+        _data = ByteData(source.length *
+            getLengthOfFirstOrZero<List<double>>(source) * bytesPerElement) {
     _updateByteDataBy2dimIterable(source, (i, j) => i * columnsNum + j,
         bytesPerElement);
   }
@@ -35,13 +35,14 @@ class DataManagerImpl implements DataManager {
       this._typedListHelper,
   ) :
         rowsNum = source.length,
-        columnsNum = source.first.length,
+        columnsNum = getLengthOfFirstOrZero<Vector>(source),
         _rowsIndicesRange = ZRange.closedOpen(0, source.length),
-        _colsIndicesRange = ZRange.closedOpen(0, source.first.length),
+        _colsIndicesRange = ZRange
+            .closedOpen(0, getLengthOfFirstOrZero<Vector>(source)),
         _rowsCache = source.toList(growable: false),
-        _colsCache = List<Vector>(source.first.length),
-        _data = ByteData(source.length * source.first.length *
-            bytesPerElement) {
+        _colsCache = List<Vector>(getLengthOfFirstOrZero<Vector>(source)),
+        _data = ByteData(source.length *
+            getLengthOfFirstOrZero<Vector>(source) * bytesPerElement) {
     _updateByteDataBy2dimIterable(source, (i, j) => i * columnsNum + j,
         bytesPerElement);
   }
@@ -52,14 +53,15 @@ class DataManagerImpl implements DataManager {
       this._dtype,
       this._typedListHelper,
   ) :
-        rowsNum = source.first.length,
+        rowsNum = getLengthOfFirstOrZero<Vector>(source),
         columnsNum = source.length,
-        _rowsIndicesRange = ZRange.closedOpen(0, source.first.length),
+        _rowsIndicesRange = ZRange
+            .closedOpen(0, getLengthOfFirstOrZero<Vector>(source)),
         _colsIndicesRange = ZRange.closedOpen(0, source.length),
-        _rowsCache = List<Vector>(source.first.length),
+        _rowsCache = List<Vector>(getLengthOfFirstOrZero<Vector>(source)),
         _colsCache = source.toList(growable: false),
-        _data = ByteData(source.length * source.first.length *
-            bytesPerElement) {
+        _data = ByteData(source.length *
+            getLengthOfFirstOrZero<Vector>(source) * bytesPerElement) {
     _updateByteDataBy2dimIterable(source, (i, j) => j * columnsNum + i,
         bytesPerElement);
   }

pubspec.yaml

@@ -1,6 +1,6 @@
 name: ml_linalg
 description: SIMD-based linear algebra (1 operation on 4 float32 values, 1 operation on 2 float64 values)
-version: 10.0.2
+version: 10.0.3
 author: Ilia Gyrdymov <ilgyrd@gmail.com>
 homepage: https://github.com/gyrdym/ml_linalg
 

test/float32_matrix_test.dart

@@ -23,7 +23,8 @@ void main() {
       expect(actual.columnsNum, 5);
     });
 
-    test('should create an instance based on an empty list', () {
+    test('should create an instance based on an empty list (`fromList` '
+        'constructor)', () {
       final actual = Float32Matrix.fromList([]);
       final expected = <double>[];
       expect(actual, equals(expected));
@@ -46,6 +47,15 @@ void main() {
       expect(actual.columnsNum, 5);
     });
 
+    test('should create an instance based on an empty list (`rows` '
+        'constructor)', () {
+      final actual = Float32Matrix.rows([]);
+      final expected = <double>[];
+      expect(actual, equals(expected));
+      expect(actual.rowsNum, 0);
+      expect(actual.columnsNum, 0);
+    });
+
     test('should create an instance with predefined vectors as matrix columns',
         () {
       final actual = Float32Matrix.columns([
@@ -64,6 +74,15 @@ void main() {
       expect(actual.columnsNum, 2);
     });
 
+    test('should create an instance based on an empty list (`columns` '
+        'constructor)', () {
+      final actual = Float32Matrix.columns([]);
+      final expected = <double>[];
+      expect(actual, equals(expected));
+      expect(actual.rowsNum, 0);
+      expect(actual.columnsNum, 0);
+    });
+
     test('should create an instance from flattened collection', () {
       final actual =
           Float32Matrix.flattened([1.0, 2.0, 3.0, 4.0, 5.0, 6.0], 2, 3);
@@ -76,6 +95,16 @@ void main() {
       expect(actual, equals(expected));
     });
 
+    test('should create an instance based on an empty list (`flattened` '
+        'constructor)', () {
+      final actual =
+      Float32Matrix.flattened([], 0, 0);
+      final expected = <double>[];
+      expect(actual.rowsNum, 0);
+      expect(actual.columnsNum, 0);
+      expect(actual, equals(expected));
+    });
+
     test('should throw an error if one tries to create a matrix from flattened '
         'collection and with unproper specified dimensions', () {
       expect(() => Float32Matrix.flattened([1.0, 2.0, 3.0, 4.0, 5.0], 2, 3),