diff --git a/kmath-core/api/kmath-core.api b/kmath-core/api/kmath-core.api
index 502628920..a109aaab5 100644
--- a/kmath-core/api/kmath-core.api
+++ b/kmath-core/api/kmath-core.api
@@ -984,6 +984,8 @@ public final class space/kscience/kmath/nd/MutableStructure1D$DefaultImpls {
 }
 
 public abstract interface class space/kscience/kmath/nd/MutableStructure2D : space/kscience/kmath/nd/MutableStructureND, space/kscience/kmath/nd/Structure2D {
+	public abstract fun getColumns ()Ljava/util/List;
+	public abstract fun getRows ()Ljava/util/List;
 	public abstract fun set (IILjava/lang/Object;)V
 }
 
@@ -2608,6 +2610,15 @@ public final class space/kscience/kmath/structures/VirtualBuffer : space/kscienc
 	public fun iterator ()Ljava/util/Iterator;
 }
 
+public final class space/kscience/kmath/structures/VirtualMutableBuffer : space/kscience/kmath/structures/MutableBuffer {
+	public fun <init> (ILkotlin/jvm/functions/Function1;)V
+	public fun copy ()Lspace/kscience/kmath/structures/MutableBuffer;
+	public fun get (I)Ljava/lang/Object;
+	public fun getSize ()I
+	public fun iterator ()Ljava/util/Iterator;
+	public fun set (ILjava/lang/Object;)V
+}
+
 public abstract interface class space/kscience/kmath/tensors/AnalyticTensorAlgebra : space/kscience/kmath/tensors/OrderedTensorAlgebra, space/kscience/kmath/tensors/TensorPartialDivisionAlgebra {
 	public abstract fun acos (Lspace/kscience/kmath/nd/MutableStructureND;)Lspace/kscience/kmath/nd/MutableStructureND;
 	public abstract fun acosh (Lspace/kscience/kmath/nd/MutableStructureND;)Lspace/kscience/kmath/nd/MutableStructureND;
@@ -2709,6 +2720,7 @@ public abstract interface class space/kscience/kmath/tensors/TensorAlgebra {
 	public abstract fun cumsum (Lspace/kscience/kmath/nd/MutableStructureND;I)Lspace/kscience/kmath/nd/MutableStructureND;
 	public abstract fun diagonalEmbedding (Lspace/kscience/kmath/nd/MutableStructureND;III)Lspace/kscience/kmath/nd/MutableStructureND;
 	public abstract fun dot (Lspace/kscience/kmath/nd/MutableStructureND;Lspace/kscience/kmath/nd/MutableStructureND;)Lspace/kscience/kmath/nd/MutableStructureND;
+	public abstract fun eq (Lspace/kscience/kmath/nd/MutableStructureND;Lspace/kscience/kmath/nd/MutableStructureND;Ljava/lang/Object;)Z
 	public abstract fun eye (I)Lspace/kscience/kmath/nd/MutableStructureND;
 	public abstract fun flatten (Lspace/kscience/kmath/nd/MutableStructureND;II)Lspace/kscience/kmath/nd/MutableStructureND;
 	public abstract fun full (Ljava/lang/Object;[I)Lspace/kscience/kmath/nd/MutableStructureND;
@@ -2970,9 +2982,10 @@ public class space/kscience/kmath/tensors/core/DoubleTensorAlgebra : space/kscie
 	public fun divAssign (Lspace/kscience/kmath/tensors/core/DoubleTensor;Lspace/kscience/kmath/tensors/core/DoubleTensor;)V
 	public synthetic fun dot (Lspace/kscience/kmath/nd/MutableStructureND;Lspace/kscience/kmath/nd/MutableStructureND;)Lspace/kscience/kmath/nd/MutableStructureND;
 	public fun dot (Lspace/kscience/kmath/tensors/core/DoubleTensor;Lspace/kscience/kmath/tensors/core/DoubleTensor;)Lspace/kscience/kmath/tensors/core/DoubleTensor;
-	public final fun eq (Lspace/kscience/kmath/tensors/core/DoubleTensor;Lspace/kscience/kmath/tensors/core/DoubleTensor;D)Z
+	public synthetic fun eq (Lspace/kscience/kmath/nd/MutableStructureND;Lspace/kscience/kmath/nd/MutableStructureND;Ljava/lang/Object;)Z
+	public final fun eq (Lspace/kscience/kmath/tensors/core/DoubleTensor;Lspace/kscience/kmath/tensors/core/DoubleTensor;)Z
+	public fun eq (Lspace/kscience/kmath/tensors/core/DoubleTensor;Lspace/kscience/kmath/tensors/core/DoubleTensor;D)Z
 	public final fun eq (Lspace/kscience/kmath/tensors/core/DoubleTensor;Lspace/kscience/kmath/tensors/core/DoubleTensor;Lkotlin/jvm/functions/Function2;)Z
-	public static synthetic fun eq$default (Lspace/kscience/kmath/tensors/core/DoubleTensorAlgebra;Lspace/kscience/kmath/tensors/core/DoubleTensor;Lspace/kscience/kmath/tensors/core/DoubleTensor;DILjava/lang/Object;)Z
 	public synthetic fun eye (I)Lspace/kscience/kmath/nd/MutableStructureND;
 	public fun eye (I)Lspace/kscience/kmath/tensors/core/DoubleTensor;
 	public synthetic fun flatten (Lspace/kscience/kmath/nd/MutableStructureND;II)Lspace/kscience/kmath/nd/MutableStructureND;
diff --git a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/LinearSpace.kt b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/LinearSpace.kt
index 6a587270b..4f2afc6fa 100644
--- a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/LinearSpace.kt
+++ b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/linear/LinearSpace.kt
@@ -14,6 +14,7 @@ import kotlin.reflect.KClass
  * @param T the type of items.
  */
 public typealias Matrix<T> = Structure2D<T>
+public typealias MutableMatrix<T> = MutableStructure2D<T>
 
 /**
  * Alias or using [Buffer] as a point/vector in a many-dimensional space.
diff --git a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/Structure2D.kt b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/Structure2D.kt
index d49438b2c..762b59b28 100644
--- a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/Structure2D.kt
+++ b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/nd/Structure2D.kt
@@ -2,7 +2,9 @@ package space.kscience.kmath.nd
 
 import space.kscience.kmath.misc.UnstableKMathAPI
 import space.kscience.kmath.structures.Buffer
+import space.kscience.kmath.structures.MutableBuffer
 import space.kscience.kmath.structures.VirtualBuffer
+import space.kscience.kmath.structures.VirtualMutableBuffer
 import kotlin.reflect.KClass
 
 /**
@@ -69,6 +71,18 @@ public interface MutableStructure2D<T> : Structure2D<T>, MutableStructureND<T> {
      * @param value the value.
      */
     public operator fun set(i: Int, j: Int, value: T)
+
+    /**
+     * The buffer of rows of this structure. It gets elements from the structure dynamically.
+     */
+    override val rows: List<MutableBuffer<T>>
+        get() = List(rowNum) { i -> VirtualMutableBuffer(colNum) { j -> get(i, j) } }
+
+    /**
+     * The buffer of columns of this structure. It gets elements from the structure dynamically.
+     */
+    override val columns: List<MutableBuffer<T>>
+        get() = List(colNum) { j -> VirtualMutableBuffer(rowNum) { i -> get(i, j) } }
 }
 
 /**
diff --git a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/Buffer.kt b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/Buffer.kt
index c85c6c5e3..72a6e3cae 100644
--- a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/Buffer.kt
+++ b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/structures/Buffer.kt
@@ -223,11 +223,7 @@ public inline class MutableListBuffer<T>(public val list: MutableList<T>) : Muta
 }
 
 /**
-<<<<<<< HEAD
  * Returns an [MutableListBuffer] that wraps the original list.
-=======
- * Returns an [ListBuffer] that wraps the original list.
->>>>>>> dev
  */
 public fun <T> MutableList<T>.asMutableBuffer(): MutableListBuffer<T> = MutableListBuffer(this)
 
@@ -286,6 +282,24 @@ public class VirtualBuffer<T>(override val size: Int, private val generator: (In
     override operator fun iterator(): Iterator<T> = (0 until size).asSequence().map(generator).iterator()
 }
 
+public class VirtualMutableBuffer<T>(override val size: Int, private val generator: (Int) -> T) : MutableBuffer<T> {
+
+    private val bufferHolder: MutableListBuffer<T> = (0 until size).map(generator).toMutableList().asMutableBuffer()
+
+    override operator fun get(index: Int): T {
+        if (index < 0 || index >= size) throw IndexOutOfBoundsException("Expected index from 0 to ${size - 1}, but found $index")
+        return bufferHolder[index]
+    }
+
+    override operator fun iterator(): Iterator<T> = bufferHolder.iterator()
+
+    override fun set(index: Int, value: T) {
+        bufferHolder[index] = value
+    }
+
+    override fun copy(): MutableBuffer<T> = bufferHolder.copy()
+}
+
 /**
  * Convert this buffer to read-only buffer.
  */
diff --git a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/tensors/TensorPartialDivisionAlgebra.kt b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/tensors/TensorPartialDivisionAlgebra.kt
index 9f70f9621..54417e842 100644
--- a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/tensors/TensorPartialDivisionAlgebra.kt
+++ b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/tensors/TensorPartialDivisionAlgebra.kt
@@ -9,8 +9,8 @@ public interface TensorPartialDivisionAlgebra<T, TensorType : TensorStructure<T>
     public operator fun TensorType.divAssign(other: TensorType)
 
     //https://pytorch.org/docs/stable/generated/torch.mean.html#torch.mean
-    public fun TensorType.mean(dim: Int, keepDim: Boolean): TensorType
+    public fun TensorType.mean(dim: Int = 0, keepDim: Boolean = false): TensorType
 
     //https://pytorch.org/docs/stable/generated/torch.var.html#torch.var
-    public fun TensorType.variance(dim: Int, unbiased: Boolean, keepDim: Boolean): TensorType
+    public fun TensorType.variance(dim: Int = 0, unbiased: Boolean = true, keepDim: Boolean = false): TensorType
 }
diff --git a/kmath-core/src/commonTest/kotlin/space/kscience/kmath/tensors/core/TestDoubleLinearOpsAlgebra.kt b/kmath-core/src/commonTest/kotlin/space/kscience/kmath/tensors/core/TestDoubleLinearOpsAlgebra.kt
index 2da79382f..d77f33f9d 100644
--- a/kmath-core/src/commonTest/kotlin/space/kscience/kmath/tensors/core/TestDoubleLinearOpsAlgebra.kt
+++ b/kmath-core/src/commonTest/kotlin/space/kscience/kmath/tensors/core/TestDoubleLinearOpsAlgebra.kt
@@ -70,4 +70,14 @@ class TestDoubleLinearOpsTensorAlgebra {
         assertTrue { invTensor.shape contentEquals expectedShape }
         assertTrue { invTensor.buffer.array().epsEqual(expectedBuffer) }
     }
+
+    @Test
+    fun testScalarProduct() = DoubleLinearOpsTensorAlgebra {
+        val a = fromArray(intArrayOf(3), doubleArrayOf(1.8,2.5, 6.8))
+        val b = fromArray(intArrayOf(3), doubleArrayOf(5.5,2.6, 6.4))
+        DoubleReduceOpsTensorAlgebra {
+            assertEquals(a.dot(b).value(), 59.92)
+        }
+
+    }
 }