Fix linear indexing bug when ndarray is noncontiguous

Author: kgryte

lib/node_modules/@stdlib/ndarray/base/ctor/lib/iget.js

@@ -36,13 +36,15 @@ function iget( idx ) {
 	var s;
 	var i;
 
-	// Trivial case where we have all positive strides...
-	if ( this._iterationOrder === 1 ) {
-		return this._buffer[ this._offset + idx ];
-	}
-	// Trivial case where we have all negative strides...
-	if ( this._iterationOrder === -1 ) {
-		return this._buffer[ this._offset - idx ];
+	if ( this._flags.ROW_MAJOR_CONTIGUOUS || this._flags.COLUMN_MAJOR_CONTIGUOUS ) { // eslint-disable-line max-len
+		// Trivial case where we have all positive strides...
+		if ( this._iterationOrder === 1 ) {
+			return this._buffer[ this._offset + idx ];
+		}
+		// Trivial case where we have all negative strides...
+		if ( this._iterationOrder === -1 ) {
+			return this._buffer[ this._offset - idx ];
+		}
 	}
 	// The approach which follows is to resolve a view index to its subscripts and then plug the subscripts into the standard formula for computing the linear index in the underlying data buffer...
 	shape = this._shape;

lib/node_modules/@stdlib/ndarray/base/ctor/lib/iset.js

@@ -37,15 +37,17 @@ function iset( idx, v ) {
 	var s;
 	var i;
 
-	// Trivial case where we have all positive strides...
-	if ( this._iterationOrder === 1 ) {
-		this._buffer[ this._offset + idx ] = v;
-		return this;
-	}
-	// Trivial case where we have all negative strides...
-	if ( this._iterationOrder === -1 ) {
-		this._buffer[ this._offset - idx ] = v;
-		return this;
+	if ( this._flags.ROW_MAJOR_CONTIGUOUS || this._flags.COLUMN_MAJOR_CONTIGUOUS ) { // eslint-disable-line max-len
+		// Trivial case where we have all positive strides...
+		if ( this._iterationOrder === 1 ) {
+			this._buffer[ this._offset + idx ] = v;
+			return this;
+		}
+		// Trivial case where we have all negative strides...
+		if ( this._iterationOrder === -1 ) {
+			this._buffer[ this._offset - idx ] = v;
+			return this;
+		}
 	}
 	// The approach which follows is to resolve a view index to its subscripts and then plug the subscripts into the standard formula for computing the linear index in the underlying data buffer...
 	shape = this._shape;

lib/node_modules/@stdlib/ndarray/base/ctor/test/test.js

@@ -1136,6 +1136,38 @@ tape( 'an ndarray constructor returns an instance which has an `iget` method for
 	t.end();
 });
 
+tape( 'an ndarray constructor returns an instance which has an `iget` method for retrieving an array element using a linear index (row-major; noncontiguous)', function test( t ) {
+	var strides;
+	var buffer;
+	var offset;
+	var dtype;
+	var order;
+	var shape;
+	var arr;
+	var f;
+
+	dtype = 'float64';
+	buffer = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
+	shape = [ 2, 2, 1 ];
+	order = 'row-major';
+	strides = [ 4, 1, 1 ];
+	offset = 0;
+
+	f = ctor( dtype, shape.length );
+	arr = f( buffer, shape, strides, offset, order );
+
+	t.strictEqual( hasOwnProp( arr, 'iget' ), false, 'does not have own property' );
+	t.strictEqual( hasProp( arr, 'iget' ), true, 'has property' );
+	t.strictEqual( isFunction( arr.iget ), true, 'has method' );
+
+	t.strictEqual( arr.iget( 0 ), 1.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 1 ), 2.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 2 ), 5.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 3 ), 6.0, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'an ndarray constructor returns an instance which has an `iget` method for retrieving an array element using a linear index (column-major)', function test( t ) {
 	var strides;
 	var buffer;
@@ -1264,6 +1296,38 @@ tape( 'an ndarray constructor returns an instance which has an `iget` method for
 	t.end();
 });
 
+tape( 'an ndarray constructor returns an instance which has an `iget` method for retrieving an array element using a linear index (column-major; noncontiguous)', function test( t ) {
+	var strides;
+	var buffer;
+	var offset;
+	var dtype;
+	var order;
+	var shape;
+	var arr;
+	var f;
+
+	dtype = 'float64';
+	buffer = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
+	shape = [ 2, 2, 1 ];
+	order = 'column-major';
+	strides = [ 1, 4, 8 ];
+	offset = 0;
+
+	f = ctor( dtype, shape.length );
+	arr = f( buffer, shape, strides, offset, order );
+
+	t.strictEqual( hasOwnProp( arr, 'iget' ), false, 'does not have own property' );
+	t.strictEqual( hasProp( arr, 'iget' ), true, 'has property' );
+	t.strictEqual( isFunction( arr.iget ), true, 'has method' );
+
+	t.strictEqual( arr.iget( 0 ), 1.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 1 ), 2.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 2 ), 5.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 3 ), 6.0, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'an ndarray constructor returns an instance which has a `set` method for setting an array element using subscripts (row-major)', function test( t ) {
 	var strides;
 	var buffer;
@@ -1732,6 +1796,45 @@ tape( 'an ndarray constructor returns an instance which has an `iset` method for
 	t.end();
 });
 
+tape( 'an ndarray constructor returns an instance which has an `iset` method for setting an array element using a linear index (row-major; noncontiguous)', function test( t ) {
+	var strides;
+	var buffer;
+	var offset;
+	var dtype;
+	var order;
+	var shape;
+	var arr;
+	var f;
+
+	dtype = 'generic';
+	buffer = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ];
+	shape = [ 2, 2, 1 ];
+	order = 'row-major';
+	strides = [ 4, 1, 1 ];
+	offset = 0;
+
+	f = ctor( dtype, shape.length );
+	arr = f( buffer, shape, strides, offset, order );
+
+	t.strictEqual( hasOwnProp( arr, 'iset' ), false, 'does not have own property' );
+	t.strictEqual( hasProp( arr, 'iset' ), true, 'has property' );
+	t.strictEqual( isFunction( arr.iset ), true, 'has method' );
+
+	arr.iset( 0, -5.0 );
+	arr.iset( 1, -6.0 );
+	arr.iset( 2, -7.0 );
+	arr.iset( 3, -8.0 );
+
+	t.strictEqual( arr.iget( 0 ), -5.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 1 ), -6.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 2 ), -7.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 3 ), -8.0, 'returns expected value' );
+
+	t.deepEqual( buffer, [ -5.0, -6.0, 3.0, 4.0, -7.0, -8.0, 7.0, 8.0 ], 'has expected values' );
+
+	t.end();
+});
+
 tape( 'an ndarray constructor returns an instance which has an `iset` method for setting an array element using a linear index (column-major)', function test( t ) {
 	var strides;
 	var buffer;
@@ -1888,6 +1991,45 @@ tape( 'an ndarray constructor returns an instance which has an `iset` method for
 	t.end();
 });
 
+tape( 'an ndarray constructor returns an instance which has an `iset` method for setting an array element using a linear index (column-major; noncontiguous)', function test( t ) {
+	var strides;
+	var buffer;
+	var offset;
+	var dtype;
+	var order;
+	var shape;
+	var arr;
+	var f;
+
+	dtype = 'generic';
+	buffer = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ];
+	shape = [ 2, 2, 1 ];
+	order = 'column-major';
+	strides = [ 1, 4, 8 ];
+	offset = 0;
+
+	f = ctor( dtype, shape.length );
+	arr = f( buffer, shape, strides, offset, order );
+
+	t.strictEqual( hasOwnProp( arr, 'iset' ), false, 'does not have own property' );
+	t.strictEqual( hasProp( arr, 'iset' ), true, 'has property' );
+	t.strictEqual( isFunction( arr.iset ), true, 'has method' );
+
+	arr.iset( 0, -5.0 );
+	arr.iset( 1, -6.0 );
+	arr.iset( 2, -7.0 );
+	arr.iset( 3, -8.0 );
+
+	t.strictEqual( arr.iget( 0 ), -5.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 1 ), -6.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 2 ), -7.0, 'returns expected value' );
+	t.strictEqual( arr.iget( 3 ), -8.0, 'returns expected value' );
+
+	t.deepEqual( buffer, [ -5.0, -6.0, 3.0, 4.0, -7.0, -8.0, 7.0, 8.0 ], 'has expected values' );
+
+	t.end();
+});
+
 tape( 'an ndarray constructor returns an instance which has a `get` method for retrieving an array element using subscripts (row-major; codegen=false)', function test( t ) {
 	var strides;
 	var buffer;