From 0e215c74756a539a503a2fd8fe784e081778ab8c Mon Sep 17 00:00:00 2001
From: mehbark <terezi@pyrope.net>
Date: Sun, 15 Jan 2023 20:36:26 -0500
Subject: [PATCH] remove redundant row-ops

---
 src/matrix/auto.clj |  3 ++-
 src/matrix/base.clj | 11 +++++++++++
 src/matrix/core.clj |  2 +-
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/matrix/auto.clj b/src/matrix/auto.clj
index dbe4df4..cd0e181 100644
--- a/src/matrix/auto.clj
+++ b/src/matrix/auto.clj
@@ -76,7 +76,8 @@
         after-g-elim (apply-all-at-once m g-elim-steps)
         bsub-steps   (back-sub after-g-elim)
         after-bsub   (apply-all-at-once after-g-elim bsub-steps)]
-    [(concat g-elim-steps bsub-steps)
+    [(filter (comp not is-redundant)
+             (concat g-elim-steps bsub-steps))
      after-bsub]))
 
 (def auto-steps (comp first auto-steps-and-final))
diff --git a/src/matrix/base.clj b/src/matrix/base.clj
index b8aad46..601e213 100644
--- a/src/matrix/base.clj
+++ b/src/matrix/base.clj
@@ -113,3 +113,14 @@
         (map #(map f %))
         (map to-vec)
         to-vec)))
+
+(defn is-redundant
+  "Takes a row op and returns whether it IS redundant"
+  [op]
+  (if-let [[op-type inner] (opspec/conform op)]
+    (case op-type
+      :swap (= (:swap inner)     ; swapping a row with itself
+               (:with inner))
+      :add  (= 0 (:times inner)) ; adding 0 times a row to another row
+      :mul  (= 1 (:by inner))    ; multiplying a row by 1
+      )))
diff --git a/src/matrix/core.clj b/src/matrix/core.clj
index c051ae4..7fec08c 100644
--- a/src/matrix/core.clj
+++ b/src/matrix/core.clj
@@ -25,4 +25,4 @@
 ; DONE: solving id-matrix
 ; DONE: solving gaussian-eliminated matrix
 ; DONE: automation 
-; TODO: remove redundant row ops
+; DONE: remove redundant row ops