diff --git a/examples/src/main/kotlin/space/kscience/kmath/structures/typeSafeDimensions.kt b/examples/src/main/kotlin/space/kscience/kmath/structures/typeSafeDimensions.kt
index 955f86fa9..c28b566b9 100644
--- a/examples/src/main/kotlin/space/kscience/kmath/structures/typeSafeDimensions.kt
+++ b/examples/src/main/kotlin/space/kscience/kmath/structures/typeSafeDimensions.kt
@@ -19,7 +19,7 @@ private fun DMatrixContext<Double, *>.simple() {
 }
 
 private object D5 : Dimension {
-    override val dim: UInt = 5u
+    override val dim: Int = 5
 }
 
 private fun DMatrixContext<Double, *>.custom() {
diff --git a/kmath-commons/src/main/kotlin/space/kscience/kmath/commons/random/CMRandomGeneratorWrapper.kt b/kmath-commons/src/main/kotlin/space/kscience/kmath/commons/random/CMRandomGeneratorWrapper.kt
index afbfd9a24..6aeebb68c 100644
--- a/kmath-commons/src/main/kotlin/space/kscience/kmath/commons/random/CMRandomGeneratorWrapper.kt
+++ b/kmath-commons/src/main/kotlin/space/kscience/kmath/commons/random/CMRandomGeneratorWrapper.kt
@@ -8,6 +8,7 @@ package space.kscience.kmath.commons.random
 import kotlinx.coroutines.runBlocking
 import space.kscience.kmath.misc.PerformancePitfall
 import space.kscience.kmath.samplers.GaussianSampler
+import space.kscience.kmath.misc.toIntExact
 import space.kscience.kmath.stat.RandomGenerator
 import space.kscience.kmath.stat.next
 
@@ -28,7 +29,7 @@ public class CMRandomGeneratorWrapper(
     }
 
     override fun setSeed(seed: Long) {
-        setSeed(seed.toInt())
+        setSeed(seed.toIntExact())
     }
 
     override fun nextBytes(bytes: ByteArray) {
diff --git a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/misc/numbers.kt b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/misc/numbers.kt
new file mode 100644
index 000000000..f879a06d5
--- /dev/null
+++ b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/misc/numbers.kt
@@ -0,0 +1,8 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.misc
+
+public expect fun Long.toIntExact(): Int
diff --git a/kmath-core/src/jsMain/kotlin/space/kscience/kmath/misc/numbers.kt b/kmath-core/src/jsMain/kotlin/space/kscience/kmath/misc/numbers.kt
new file mode 100644
index 000000000..68a3c995b
--- /dev/null
+++ b/kmath-core/src/jsMain/kotlin/space/kscience/kmath/misc/numbers.kt
@@ -0,0 +1,12 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.misc
+
+public actual fun Long.toIntExact(): Int {
+    val i = toInt()
+    if (i.toLong() == this) throw ArithmeticException("integer overflow")
+    return i
+}
diff --git a/kmath-core/src/jvmMain/kotlin/space/kscience/kmath/misc/numbersJVM.kt b/kmath-core/src/jvmMain/kotlin/space/kscience/kmath/misc/numbersJVM.kt
new file mode 100644
index 000000000..5ba0dbc9b
--- /dev/null
+++ b/kmath-core/src/jvmMain/kotlin/space/kscience/kmath/misc/numbersJVM.kt
@@ -0,0 +1,8 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.misc
+
+public actual fun Long.toIntExact(): Int = Math.toIntExact(this)
diff --git a/kmath-core/src/nativeMain/kotlin/space/kscience/kmath/misc/numbers.kt b/kmath-core/src/nativeMain/kotlin/space/kscience/kmath/misc/numbers.kt
new file mode 100644
index 000000000..68a3c995b
--- /dev/null
+++ b/kmath-core/src/nativeMain/kotlin/space/kscience/kmath/misc/numbers.kt
@@ -0,0 +1,12 @@
+/*
+ * Copyright 2018-2021 KMath contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package space.kscience.kmath.misc
+
+public actual fun Long.toIntExact(): Int {
+    val i = toInt()
+    if (i.toLong() == this) throw ArithmeticException("integer overflow")
+    return i
+}
diff --git a/kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Dimensions.kt b/kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
similarity index 67%
rename from kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Dimensions.kt
rename to kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
index 8b17d252f..e57c22834 100644
--- a/kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Dimensions.kt
+++ b/kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
@@ -8,47 +8,47 @@ package space.kscience.kmath.dimensions
 import kotlin.reflect.KClass
 
 /**
- * Represents a quantity of dimensions in certain structure.
+ * Represents a quantity of dimensions in certain structure. **This interface must be implemented only by objects.**
  *
  * @property dim The number of dimensions.
  */
 public interface Dimension {
-    public val dim: UInt
+    public val dim: Int
 
     public companion object
 }
 
-public fun <D : Dimension> KClass<D>.dim(): UInt = Dimension.resolve(this).dim
+public fun <D : Dimension> KClass<D>.dim(): Int = Dimension.resolve(this).dim
 
 public expect fun <D : Dimension> Dimension.Companion.resolve(type: KClass<D>): D
 
 /**
  * Finds or creates [Dimension] with [Dimension.dim] equal to [dim].
  */
-public expect fun Dimension.Companion.of(dim: UInt): Dimension
+public expect fun Dimension.Companion.of(dim: Int): Dimension
 
 /**
  * Finds [Dimension.dim] of given type [D].
  */
-public inline fun <reified D : Dimension> Dimension.Companion.dim(): UInt = D::class.dim()
+public inline fun <reified D : Dimension> Dimension.Companion.dim(): Int = D::class.dim()
 
 /**
  * Type representing 1 dimension.
  */
 public object D1 : Dimension {
-    override val dim: UInt get() = 1U
+    override val dim: Int get() = 1
 }
 
 /**
  * Type representing 2 dimensions.
  */
 public object D2 : Dimension {
-    override val dim: UInt get() = 2U
+    override val dim: Int get() = 2
 }
 
 /**
  * Type representing 3 dimensions.
  */
 public object D3 : Dimension {
-    override val dim: UInt get() = 3U
+    override val dim: Int get() = 3
 }
diff --git a/kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Wrappers.kt b/kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Wrappers.kt
index a2ee14301..deb297913 100644
--- a/kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Wrappers.kt
+++ b/kmath-dimensions/src/commonMain/kotlin/space/kscience/kmath/dimensions/Wrappers.kt
@@ -23,11 +23,11 @@ public interface DMatrix<out T, R : Dimension, C : Dimension> : Structure2D<T> {
          * Coerces a regular matrix to a matrix with type-safe dimensions and throws a error if coercion failed
          */
         public inline fun <T, reified R : Dimension, reified C : Dimension> coerce(structure: Structure2D<T>): DMatrix<T, R, C> {
-            require(structure.rowNum == Dimension.dim<R>().toInt()) {
+            require(structure.rowNum == Dimension.dim<R>()) {
                 "Row number mismatch: expected ${Dimension.dim<R>()} but found ${structure.rowNum}"
             }
 
-            require(structure.colNum == Dimension.dim<C>().toInt()) {
+            require(structure.colNum == Dimension.dim<C>()) {
                 "Column number mismatch: expected ${Dimension.dim<C>()} but found ${structure.colNum}"
             }
 
@@ -61,7 +61,7 @@ public value class DMatrixWrapper<out T, R : Dimension, C : Dimension>(
 public interface DPoint<out T, D : Dimension> : Point<T> {
     public companion object {
         public inline fun <T, reified D : Dimension> coerce(point: Point<T>): DPoint<T, D> {
-            require(point.size == Dimension.dim<D>().toInt()) {
+            require(point.size == Dimension.dim<D>()) {
                 "Vector dimension mismatch: expected ${Dimension.dim<D>()}, but found ${point.size}"
             }
 
@@ -92,11 +92,11 @@ public value class DPointWrapper<out T, D : Dimension>(public val point: Point<T
 @JvmInline
 public value class DMatrixContext<T : Any, out A : Ring<T>>(public val context: LinearSpace<T, A>) {
     public inline fun <reified R : Dimension, reified C : Dimension> Matrix<T>.coerce(): DMatrix<T, R, C> {
-        require(rowNum == Dimension.dim<R>().toInt()) {
+        require(rowNum == Dimension.dim<R>()) {
             "Row number mismatch: expected ${Dimension.dim<R>()} but found $rowNum"
         }
 
-        require(colNum == Dimension.dim<C>().toInt()) {
+        require(colNum == Dimension.dim<C>()) {
             "Column number mismatch: expected ${Dimension.dim<C>()} but found $colNum"
         }
 
@@ -111,7 +111,7 @@ public value class DMatrixContext<T : Any, out A : Ring<T>>(public val context:
     ): DMatrix<T, R, C> {
         val rows = Dimension.dim<R>()
         val cols = Dimension.dim<C>()
-        return context.buildMatrix(rows.toInt(), cols.toInt(), initializer).coerce()
+        return context.buildMatrix(rows, cols, initializer).coerce()
     }
 
     public inline fun <reified D : Dimension> point(noinline initializer: A.(Int) -> T): DPoint<T, D> {
@@ -119,7 +119,7 @@ public value class DMatrixContext<T : Any, out A : Ring<T>>(public val context:
 
         return DPoint.coerceUnsafe(
             context.buildVector(
-                size.toInt(),
+                size,
                 initializer
             )
         )
@@ -167,4 +167,4 @@ public inline fun <reified D : Dimension> DMatrixContext<Double, DoubleField>.on
 public inline fun <reified R : Dimension, reified C : Dimension> DMatrixContext<Double, DoubleField>.zero(): DMatrix<Double, R, C> =
     produce { _, _ ->
         0.0
-    }
\ No newline at end of file
+    }
diff --git a/kmath-dimensions/src/jsMain/kotlin/space/kscience/kmath/dimensions/dimJs.kt b/kmath-dimensions/src/jsMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
similarity index 62%
rename from kmath-dimensions/src/jsMain/kotlin/space/kscience/kmath/dimensions/dimJs.kt
rename to kmath-dimensions/src/jsMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
index 27912f5bc..610e8b4c0 100644
--- a/kmath-dimensions/src/jsMain/kotlin/space/kscience/kmath/dimensions/dimJs.kt
+++ b/kmath-dimensions/src/jsMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
@@ -7,17 +7,17 @@ package space.kscience.kmath.dimensions
 
 import kotlin.reflect.KClass
 
-private val dimensionMap: MutableMap<UInt, Dimension> = hashMapOf(1u to D1, 2u to D2, 3u to D3)
+private val dimensionMap: MutableMap<Int, Dimension> = hashMapOf(1 to D1, 2 to D2, 3 to D3)
 
 @Suppress("UNCHECKED_CAST")
 public actual fun <D : Dimension> Dimension.Companion.resolve(type: KClass<D>): D = dimensionMap
     .entries
-    .map(MutableMap.MutableEntry<UInt, Dimension>::value)
+    .map(MutableMap.MutableEntry<Int, Dimension>::value)
     .find { it::class == type } as? D
     ?: error("Can't resolve dimension $type")
 
-public actual fun Dimension.Companion.of(dim: UInt): Dimension = dimensionMap.getOrPut(dim) {
+public actual fun Dimension.Companion.of(dim: Int): Dimension = dimensionMap.getOrPut(dim) {
     object : Dimension {
-        override val dim: UInt get() = dim
+        override val dim: Int get() = dim
     }
 }
diff --git a/kmath-dimensions/src/jvmMain/kotlin/space/kscience/kmath/dimensions/dimJvm.kt b/kmath-dimensions/src/jvmMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
similarity index 69%
rename from kmath-dimensions/src/jvmMain/kotlin/space/kscience/kmath/dimensions/dimJvm.kt
rename to kmath-dimensions/src/jvmMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
index f21a3e18f..e6d8b3b35 100644
--- a/kmath-dimensions/src/jvmMain/kotlin/space/kscience/kmath/dimensions/dimJvm.kt
+++ b/kmath-dimensions/src/jvmMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
@@ -3,6 +3,8 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
+@file:JvmName("DimensionJVM")
+
 package space.kscience.kmath.dimensions
 
 import kotlin.reflect.KClass
@@ -10,12 +12,12 @@ import kotlin.reflect.KClass
 public actual fun <D : Dimension> Dimension.Companion.resolve(type: KClass<D>): D =
     type.objectInstance ?: error("No object instance for dimension class")
 
-public actual fun Dimension.Companion.of(dim: UInt): Dimension = when (dim) {
-    1u -> D1
-    2u -> D2
-    3u -> D3
+public actual fun Dimension.Companion.of(dim: Int): Dimension = when (dim) {
+    1 -> D1
+    2 -> D2
+    3 -> D3
 
     else -> object : Dimension {
-        override val dim: UInt get() = dim
+        override val dim: Int get() = dim
     }
-}
\ No newline at end of file
+}
diff --git a/kmath-dimensions/src/nativeMain/kotlin/space/kscience/kmath/dimensions/dimNative.kt b/kmath-dimensions/src/nativeMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
similarity index 65%
rename from kmath-dimensions/src/nativeMain/kotlin/space/kscience/kmath/dimensions/dimNative.kt
rename to kmath-dimensions/src/nativeMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
index 9aa58e64a..64edbe935 100644
--- a/kmath-dimensions/src/nativeMain/kotlin/space/kscience/kmath/dimensions/dimNative.kt
+++ b/kmath-dimensions/src/nativeMain/kotlin/space/kscience/kmath/dimensions/Dimension.kt
@@ -9,17 +9,17 @@ import kotlin.native.concurrent.ThreadLocal
 import kotlin.reflect.KClass
 
 @ThreadLocal
-private val dimensionMap: MutableMap<UInt, Dimension> = hashMapOf(1u to D1, 2u to D2, 3u to D3)
+private val dimensionMap: MutableMap<Int, Dimension> = hashMapOf(1 to D1, 2 to D2, 3 to D3)
 
 @Suppress("UNCHECKED_CAST")
 public actual fun <D : Dimension> Dimension.Companion.resolve(type: KClass<D>): D = dimensionMap
     .entries
-    .map(MutableMap.MutableEntry<UInt, Dimension>::value)
+    .map(MutableMap.MutableEntry<Int, Dimension>::value)
     .find { it::class == type } as? D
     ?: error("Can't resolve dimension $type")
 
-public actual fun Dimension.Companion.of(dim: UInt): Dimension = dimensionMap.getOrPut(dim) {
+public actual fun Dimension.Companion.of(dim: Int): Dimension = dimensionMap.getOrPut(dim) {
     object : Dimension {
-        override val dim: UInt get() = dim
+        override val dim: Int get() = dim
     }
 }
diff --git a/kmath-nd4j/src/main/kotlin/space/kscience/kmath/nd4j/arrays.kt b/kmath-nd4j/src/main/kotlin/space/kscience/kmath/nd4j/arrays.kt
index 75a334ca7..3ca756600 100644
--- a/kmath-nd4j/src/main/kotlin/space/kscience/kmath/nd4j/arrays.kt
+++ b/kmath-nd4j/src/main/kotlin/space/kscience/kmath/nd4j/arrays.kt
@@ -5,4 +5,6 @@
 
 package space.kscience.kmath.nd4j
 
-internal fun LongArray.toIntArray(): IntArray = IntArray(size) { this[it].toInt() }
+import space.kscience.kmath.misc.toIntExact
+
+internal fun LongArray.toIntArray(): IntArray = IntArray(size) { this[it].toIntExact() }
diff --git a/kmath-stat/src/commonMain/kotlin/space/kscience/kmath/samplers/PoissonSampler.kt b/kmath-stat/src/commonMain/kotlin/space/kscience/kmath/samplers/PoissonSampler.kt
index 2177e41ab..96131aa4b 100644
--- a/kmath-stat/src/commonMain/kotlin/space/kscience/kmath/samplers/PoissonSampler.kt
+++ b/kmath-stat/src/commonMain/kotlin/space/kscience/kmath/samplers/PoissonSampler.kt
@@ -7,6 +7,7 @@ package space.kscience.kmath.samplers
 
 import space.kscience.kmath.chains.BlockingIntChain
 import space.kscience.kmath.internal.InternalUtils
+import space.kscience.kmath.misc.toIntExact
 import space.kscience.kmath.stat.RandomGenerator
 import space.kscience.kmath.stat.Sampler
 import space.kscience.kmath.structures.IntBuffer
@@ -119,7 +120,7 @@ public class LargeMeanPoissonSampler(public val mean: Double) : Sampler<Int> {
             val gaussian = ZigguratNormalizedGaussianSampler.sample(generator)
 
             val smallMeanPoissonSampler = if (mean - lambda < Double.MIN_VALUE) {
-               null
+                null
             } else {
                 KempSmallMeanPoissonSampler(mean - lambda).sample(generator)
             }
@@ -188,7 +189,7 @@ public class LargeMeanPoissonSampler(public val mean: Double) : Sampler<Int> {
                 }
             }
 
-            return min(y2 + y.toLong(), Int.MAX_VALUE.toLong()).toInt()
+            return min(y2 + y.toLong(), Int.MAX_VALUE.toLong()).toIntExact()
         }
 
         override fun nextBufferBlocking(size: Int): IntBuffer = IntBuffer(size) { nextBlocking() }
diff --git a/kmath-stat/src/commonMain/kotlin/space/kscience/kmath/samplers/ZigguratNormalizedGaussianSampler.kt b/kmath-stat/src/commonMain/kotlin/space/kscience/kmath/samplers/ZigguratNormalizedGaussianSampler.kt
index 24148271d..81b8c3d4b 100644
--- a/kmath-stat/src/commonMain/kotlin/space/kscience/kmath/samplers/ZigguratNormalizedGaussianSampler.kt
+++ b/kmath-stat/src/commonMain/kotlin/space/kscience/kmath/samplers/ZigguratNormalizedGaussianSampler.kt
@@ -6,6 +6,7 @@
 package space.kscience.kmath.samplers
 
 import space.kscience.kmath.chains.BlockingDoubleChain
+import space.kscience.kmath.misc.toIntExact
 import space.kscience.kmath.stat.RandomGenerator
 import space.kscience.kmath.structures.DoubleBuffer
 import kotlin.math.*
@@ -58,7 +59,7 @@ public object ZigguratNormalizedGaussianSampler : NormalizedGaussianSampler {
 
     private fun sampleOne(generator: RandomGenerator): Double {
         val j = generator.nextLong()
-        val i = (j and LAST.toLong()).toInt()
+        val i = (j and LAST.toLong()).toIntExact()
         return if (abs(j) < K[i]) j * W[i] else fix(generator, j, i)
     }