From 271d7886df6c84a920eac5b88c811ede231c84f4 Mon Sep 17 00:00:00 2001
From: Alexander Nozik <altavir@gmail.com>
Date: Wed, 16 Jan 2019 19:41:36 +0300
Subject: [PATCH] Added equality to matrices

---
 .../kotlin/scientifik/kmath/linear/Matrix.kt  | 19 +++++-------------
 .../kmath/linear/StructureMatrix.kt           | 19 +++++++++++++++++-
 .../scientifik/kmath/linear/VirtualMatrix.kt  | 20 +++++++++++++++++++
 .../kmath/linear/RealLUSolverTest.kt          |  4 ++--
 4 files changed, 45 insertions(+), 17 deletions(-)

diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Matrix.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Matrix.kt
index 8cd9a6b8f..d9a14864b 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Matrix.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/Matrix.kt
@@ -152,25 +152,16 @@ interface Matrix<T : Any> : NDStructure<T> {
 /**
  * Diagonal matrix of ones. The matrix is virtual no actual matrix is created
  */
-fun <T : Any, R : Ring<T>> MatrixContext<T, R>.one(rows: Int, columns: Int): Matrix<T> {
-    return object : Matrix<T> {
-        override val rowNum: Int get() = rows
-        override val colNum: Int get() = columns
-        override val features: Set<MatrixFeature> get() = setOf(DiagonalFeature, UnitFeature)
-        override fun get(i: Int, j: Int): T = if (i == j) elementContext.one else elementContext.zero
-    }
+fun <T : Any, R : Ring<T>> MatrixContext<T, R>.one(rows: Int, columns: Int): Matrix<T>  = VirtualMatrix<T>(rows,columns){i, j->
+    if (i == j) elementContext.one else elementContext.zero
 }
 
+
 /**
  * A virtual matrix of zeroes
  */
-fun <T : Any, R : Ring<T>> MatrixContext<T, R>.zero(rows: Int, columns: Int): Matrix<T> {
-    return object : Matrix<T> {
-        override val rowNum: Int get() = rows
-        override val colNum: Int get() = columns
-        override val features: Set<MatrixFeature> get() = setOf(ZeroFeature)
-        override fun get(i: Int, j: Int): T = elementContext.zero
-    }
+fun <T : Any, R : Ring<T>> MatrixContext<T, R>.zero(rows: Int, columns: Int): Matrix<T>  = VirtualMatrix<T>(rows,columns){i, j->
+    elementContext.zero
 }
 
 
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/StructureMatrix.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/StructureMatrix.kt
index 1109297be..aa061fae2 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/StructureMatrix.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/StructureMatrix.kt
@@ -23,7 +23,7 @@ class StructureMatrixContext<T : Any, R : Ring<T>>(
     override fun point(size: Int, initializer: (Int) -> T): Point<T> = bufferFactory(size, initializer)
 }
 
-data class StructureMatrix<T : Any>(
+class StructureMatrix<T : Any>(
     val structure: NDStructure<T>,
     override val features: Set<MatrixFeature> = emptySet()
 ) : Matrix<T> {
@@ -47,4 +47,21 @@ data class StructureMatrix<T : Any>(
     override fun get(i: Int, j: Int): T = structure[i, j]
 
     override fun elements(): Sequence<Pair<IntArray, T>> = structure.elements()
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        return when (other) {
+            is StructureMatrix<*> -> return this.structure == other.structure
+            is Matrix<*> -> elements().all { (index, value) -> value == other[index] }
+            else -> false
+        }
+    }
+
+    override fun hashCode(): Int {
+        var result = structure.hashCode()
+        result = 31 * result + features.hashCode()
+        return result
+    }
+
+
 }
\ No newline at end of file
diff --git a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/VirtualMatrix.kt b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/VirtualMatrix.kt
index 59c89b197..cb7b0a08e 100644
--- a/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/VirtualMatrix.kt
+++ b/kmath-core/src/commonMain/kotlin/scientifik/kmath/linear/VirtualMatrix.kt
@@ -7,4 +7,24 @@ class VirtualMatrix<T : Any>(
     val generator: (i: Int, j: Int) -> T
 ) : Matrix<T> {
     override fun get(i: Int, j: Int): T = generator(i, j)
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is Matrix<*>) return false
+
+        if (rowNum != other.rowNum) return false
+        if (colNum != other.colNum) return false
+
+        return elements().all { (index, value) -> value == other[index] }
+    }
+
+    override fun hashCode(): Int {
+        var result = rowNum
+        result = 31 * result + colNum
+        result = 31 * result + features.hashCode()
+        result = 31 * result + generator.hashCode()
+        return result
+    }
+
+
 }
\ No newline at end of file
diff --git a/kmath-core/src/commonTest/kotlin/scientifik/kmath/linear/RealLUSolverTest.kt b/kmath-core/src/commonTest/kotlin/scientifik/kmath/linear/RealLUSolverTest.kt
index daf749e8a..54a308761 100644
--- a/kmath-core/src/commonTest/kotlin/scientifik/kmath/linear/RealLUSolverTest.kt
+++ b/kmath-core/src/commonTest/kotlin/scientifik/kmath/linear/RealLUSolverTest.kt
@@ -14,7 +14,7 @@ class RealLUSolverTest {
 //    @Test
 //    fun testInvert() {
 //        val matrix = realMatrix(2,2){}
-//        val inverted = RealLUSolver.inverse(matrix)
-//        assertTrue { Matrix.equals(matrix,inverted) }
+//        val inverted = LUSolver.real.inverse(matrix)
+//        assertEquals(matrix, inverted)
 //    }
 }
\ No newline at end of file