diff --git a/examples/build.gradle.kts b/examples/build.gradle.kts
index 3f3c06764..26fa9e76b 100644
--- a/examples/build.gradle.kts
+++ b/examples/build.gradle.kts
@@ -36,8 +36,8 @@ dependencies {
     implementation(project(":kmath-memory"))
     implementation("com.kyonifer:koma-core-ejml:0.12")
     implementation("org.jetbrains.kotlinx:kotlinx-io-jvm:0.2.0-npm-dev-6")
-    implementation("org.jetbrains.kotlinx:kotlinx.benchmark.runtime:0.2.0-dev-8")
-    "benchmarksCompile"(sourceSets.main.get().output + sourceSets.main.get().compileClasspath) //sourceSets.main.output + sourceSets.main.runtimeClasspath
+    "benchmarksImplementation"("org.jetbrains.kotlinx:kotlinx.benchmark.runtime-jvm:0.2.0-dev-8")
+    "benchmarksImplementation"(sourceSets.main.get().output.plus(sourceSets.main.get().runtimeClasspath))
 }
 
 // Configure benchmark
diff --git a/examples/src/benchmarks/kotlin/scientifik/kmath/bignum/BigIntegerBenchmark.kt b/examples/src/benchmarks/kotlin/scientifik/kmath/bignum/BigIntegerBenchmark.kt
new file mode 100644
index 000000000..fca4e22ba
--- /dev/null
+++ b/examples/src/benchmarks/kotlin/scientifik/kmath/bignum/BigIntegerBenchmark.kt
@@ -0,0 +1,38 @@
+package scientifik.kmath.bignum
+
+import org.openjdk.jmh.annotations.Benchmark
+import org.openjdk.jmh.annotations.Scope
+import org.openjdk.jmh.annotations.State
+import scientifik.kmath.operations.BigIntField
+import scientifik.kmath.operations.JBigIntegerField
+import scientifik.kmath.operations.invoke
+import kotlin.random.Random
+
+@State(Scope.Benchmark)
+class BigIntegerBenchmark {
+    var times: Int = 1000000
+
+    @Benchmark
+    fun java() {
+        val random = Random(0)
+        var sum = JBigIntegerField.zero
+        repeat(times) { sum += JBigIntegerField { number(random.nextInt()) * random.nextInt() } }
+        println("java:$sum")
+    }
+
+    @Benchmark
+    fun bignum() {
+        val random = Random(0)
+        var sum = BigIntegerRing.zero
+        repeat(times) { sum += BigIntegerRing { number(random.nextInt()) * random.nextInt() } }
+        println("bignum:$sum")
+    }
+
+    @Benchmark
+    fun bigint() {
+        val random = Random(0)
+        var sum = BigIntField.zero
+        repeat(times) { sum += BigIntField { number(random.nextInt()) * random.nextInt() } }
+        println("bigint:$sum")
+    }
+}
diff --git a/examples/src/main/kotlin/scientifik/kmath/bignum/BigIntegerBenchmark.kt b/examples/src/main/kotlin/scientifik/kmath/bignum/BigIntegerBenchmark.kt
deleted file mode 100644
index d7c97a96b..000000000
--- a/examples/src/main/kotlin/scientifik/kmath/bignum/BigIntegerBenchmark.kt
+++ /dev/null
@@ -1,52 +0,0 @@
-package scientifik.kmath.bignum
-
-import scientifik.kmath.operations.BigIntField
-import scientifik.kmath.operations.JBigIntegerField
-import scientifik.kmath.operations.invoke
-import kotlin.concurrent.thread
-import kotlin.random.Random
-import kotlin.system.measureTimeMillis
-
-private class BigIntegerBenchmark {
-    fun java() {
-        val random = Random(0)
-        var sum = JBigIntegerField.zero
-        repeat(1000000) {
-            sum += JBigIntegerField { number(random.nextInt()) * random.nextInt() }
-        }
-        println("java:$sum")
-    }
-
-    fun bignum() {
-        val random = Random(0)
-        var sum = BigIntegerRing.zero
-        repeat(1000000) { sum += BigIntegerRing { number(random.nextInt()) * random.nextInt() } }
-        println("bignum:$sum")
-    }
-
-    fun bigint() {
-        val random = Random(0)
-        var sum = BigIntField.zero
-        repeat(1000000) { sum += BigIntField { number(random.nextInt()) * random.nextInt() } }
-        println("bigint:$sum")
-    }
-}
-
-fun main() {
-    val benchmark = BigIntegerBenchmark()
-
-    thread {
-        val java = measureTimeMillis(benchmark::java)
-        println("java=$java")
-    }
-
-    thread {
-        val bignum = measureTimeMillis(benchmark::bignum)
-        println("bignum=$bignum")
-    }
-
-    thread {
-        val bigint = measureTimeMillis(benchmark::bigint)
-        println("bigint=$bigint")
-    }
-}
diff --git a/kmath-bignum/build.gradle.kts b/kmath-bignum/build.gradle.kts
index cb23be68b..659e71208 100644
--- a/kmath-bignum/build.gradle.kts
+++ b/kmath-bignum/build.gradle.kts
@@ -3,7 +3,7 @@ plugins { id("scientifik.mpp") }
 kotlin.sourceSets {
     commonMain {
         dependencies {
-            api("com.ionspin.kotlin:bignum:0.2.0")
+            api("com.ionspin.kotlin:bignum:0.1.5")
             api(project(":kmath-core"))
         }
     }
diff --git a/kmath-bignum/src/commonMain/kotlin/scientifik/kmath/bignum/BigIntegerRing.kt b/kmath-bignum/src/commonMain/kotlin/scientifik/kmath/bignum/BigIntegerRing.kt
index d99d4934b..3608256b9 100644
--- a/kmath-bignum/src/commonMain/kotlin/scientifik/kmath/bignum/BigIntegerRing.kt
+++ b/kmath-bignum/src/commonMain/kotlin/scientifik/kmath/bignum/BigIntegerRing.kt
@@ -14,8 +14,6 @@ object BigIntegerRing : Ring<BigInteger> {
     override fun add(a: BigInteger, b: BigInteger): BigInteger = a + b
     override fun multiply(a: BigInteger, k: Number): BigInteger = a * (number(k))
     override fun multiply(a: BigInteger, b: BigInteger): BigInteger = a * b
-    override fun BigInteger.unaryMinus(): BigInteger = negate()
-    override fun BigInteger.minus(b: BigInteger): BigInteger = minus(b)
     override fun BigInteger.plus(b: Number): BigInteger = plus(number(b))
     override fun BigInteger.minus(b: Number): BigInteger = minus(number(b))
     override fun BigInteger.div(k: Number): BigInteger = divide(number(k))