From 5b8d6b601e54526c0148bd391e380d305ad4496a Mon Sep 17 00:00:00 2001
From: Gleb Minaev <43728100+lounres@users.noreply.github.com>
Date: Tue, 22 Mar 2022 15:37:19 +0300
Subject: [PATCH] Added `degreeBy` to `Numbered...`.

---
 .../kscience/kmath/functions/NumberedPolynomial.kt   | 12 ++++++++++++
 .../kmath/functions/NumberedRationalFunction.kt      |  8 ++++++++
 2 files changed, 20 insertions(+)

diff --git a/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedPolynomial.kt b/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedPolynomial.kt
index 1f37a1c2b..570ccce8e 100644
--- a/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedPolynomial.kt
+++ b/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedPolynomial.kt
@@ -471,6 +471,18 @@ public open class NumberedPolynomialSpace<C, A : Ring<C>>(
                     }
                 }
             }
+    /**
+     * Counts degree of the polynomial by the specified [variable].
+     */
+    public fun NumberedPolynomial<C>.degreeBy(variable: Int): UInt =
+        coefficients.entries.maxOfOrNull { (degs, c) -> if (c.isZero()) 0u else degs.getOrElse(variable) { 0u } } ?: 0u
+    /**
+     * Counts degree of the polynomial by the specified [variables].
+     */
+    public fun NumberedPolynomial<C>.degreeBy(variables: Collection<Int>): UInt =
+        coefficients.entries.maxOfOrNull { (degs, c) ->
+            if (c.isZero()) 0u else degs.withIndex().filter { (index, _) -> index in variables }.sumOf { it.value }
+        } ?: 0u
     /**
      * Count of variables occurring in the polynomial with positive power. If there is no such variable,
      * the result is `0`.
diff --git a/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedRationalFunction.kt b/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedRationalFunction.kt
index b32f01f2a..2a4d942a6 100644
--- a/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedRationalFunction.kt
+++ b/kmath-functions/src/commonMain/kotlin/space/kscience/kmath/functions/NumberedRationalFunction.kt
@@ -126,6 +126,14 @@ public class NumberedRationalFunctionSpace<C, A: Ring<C>> (
      * And last index of the list is [lastVariable].
      */
     public val NumberedPolynomial<C>.degrees: List<UInt> get() = polynomialRing { degrees }
+    /**
+     * Counts degree of the polynomial by the specified [variable].
+     */
+    public fun NumberedPolynomial<C>.degreeBy(variable: Int): UInt = polynomialRing { degreeBy(variable) }
+    /**
+     * Counts degree of the polynomial by the specified [variables].
+     */
+    public fun NumberedPolynomial<C>.degreeBy(variables: Collection<Int>): UInt = polynomialRing { degreeBy(variables) }
     /**
      * Count of variables occurring in the polynomial with positive power. If there is no such variable,
      * the result is `0`.