From 7e7dc9f9aa8221fa0948f444bb42a36714942b7b Mon Sep 17 00:00:00 2001
From: margarita0303 <lashina.2000@gmail.com>
Date: Sat, 30 Jul 2022 21:09:50 +0300
Subject: [PATCH] added epsilon as a parameter to svdGolubKahan

---
 .../space/kscience/kmath/tensors/core/DoubleTensorAlgebra.kt | 5 +++--
 .../space/kscience/kmath/tensors/core/internal/linUtils.kt   | 3 +--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/DoubleTensorAlgebra.kt b/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/DoubleTensorAlgebra.kt
index 742a3d7a7..d83c70bd9 100644
--- a/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/DoubleTensorAlgebra.kt
+++ b/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/DoubleTensorAlgebra.kt
@@ -837,7 +837,7 @@ public open class DoubleTensorAlgebra :
         return this.svdGolubKahan()
     }
 
-    public fun StructureND<Double>.svdGolubKahan(iterations: Int = 30): Triple<DoubleTensor, DoubleTensor, DoubleTensor> {
+    public fun StructureND<Double>.svdGolubKahan(iterations: Int = 30, epsilon: Double = 1e-10): Triple<DoubleTensor, DoubleTensor, DoubleTensor> {
         val size = tensor.dimension
         val commonShape = tensor.shape.sliceArray(0 until size - 2)
         val (n, m) = tensor.shape.sliceArray(size - 2 until size)
@@ -859,7 +859,8 @@ public open class DoubleTensorAlgebra :
                     .slice(matrix.bufferStart until matrix.bufferStart + matrixSize)
                     .toDoubleArray()
             )
-            curMatrix.as2D().svdGolubKahanHelper(uTensors[index].as2D(), sTensorVectors[index], vTensors[index].as2D(), iterations)
+            curMatrix.as2D().svdGolubKahanHelper(uTensors[index].as2D(), sTensorVectors[index], vTensors[index].as2D(),
+                iterations, epsilon)
         }
 
         return Triple(uTensor.transpose(), sTensor, vTensor)
diff --git a/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/internal/linUtils.kt b/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/internal/linUtils.kt
index f6cb82bfd..9724fc335 100644
--- a/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/internal/linUtils.kt
+++ b/kmath-tensors/src/commonMain/kotlin/space/kscience/kmath/tensors/core/internal/linUtils.kt
@@ -373,7 +373,7 @@ private fun SIGN(a: Double, b: Double): Double {
         return -abs(a)
 }
 internal fun MutableStructure2D<Double>.svdGolubKahanHelper(u: MutableStructure2D<Double>, w: BufferedTensor<Double>,
-                                                            v: MutableStructure2D<Double>, iterations: Int) {
+                                                            v: MutableStructure2D<Double>, iterations: Int, epsilon: Double) {
     val shape = this.shape
     val m = shape.component1()
     val n = shape.component2()
@@ -384,7 +384,6 @@ internal fun MutableStructure2D<Double>.svdGolubKahanHelper(u: MutableStructure2
     var anorm = 0.0
     var g = 0.0
     var l = 0
-    val epsilon = 1e-10
 
     val wStart = w.bufferStart
     val wBuffer = w.mutableBuffer