From 076894989703bbac47fec55eaf1dd319b33f1572 Mon Sep 17 00:00:00 2001
From: Helmut Merz <helmutm@cy55.de>
Date: Wed, 28 May 2025 09:36:22 +0200
Subject: [PATCH] gradient-descent working with line

---
 decons.lisp      | 36 ++++++++++++++----------------------
 test-decons.lisp |  4 +---
 2 files changed, 15 insertions(+), 25 deletions(-)

diff --git a/decons.lisp b/decons.lisp
index 0915117..e345a76 100644
--- a/decons.lisp
+++ b/decons.lisp
@@ -5,10 +5,11 @@
   (:local-nicknames (:shape :scopes/shape)
                     (:util :scopes/util))
   (:export #:rapply #:rreduce #:radd #:rmul #:rsub #:rdiv
-           #:default-deviation #:l2-loss #:trial #:gradient
-           #:nabla-xp #:diff
+           #:default-deviation #:l2-loss 
+           *revisions* *alpha* #:gradient-descent
+           #:nabla-xp
            #:line
-           #:*obj* #:*trials* #:try))
+           #:*obj*))
 
 (in-package :decons)
 
@@ -60,22 +61,18 @@
              (calculated (funcall objective theta)))
         (funcall deviation (cadr dataset) calculated)))))
 
-(defclass trial ()
-  ((theta :reader theta :initarg :theta)
-   (loss :reader loss :initarg :loss)))
-
-(defmethod print-object ((tr trial) stream)
-  (shape:print-slots tr stream 'theta 'loss))
-
-(defun gradient (target dataset)
-  (let ((obj (funcall (l2-loss target) dataset)))
-    (lambda (theta)
-      (nabla-xp obj theta))))
-
 ;;;; optimization by revision (= gradient descent)
 
-(defvar *revisions* 10)
-(defvar *alpha* 0.01)
+(defparameter *revisions* 1000)
+(defparameter *alpha* 0.01)
+
+(defun gradient-descent (obj theta)
+  (flet ((try-theta (th) 
+           (mapcar (lambda (p g) (- p (* *alpha* g))) 
+                   th (nabla-xp obj th))))
+    (dotimes (ix *revisions*) 
+      (setf theta (try-theta theta)))
+    theta))
 
 ;;;; experimental differentiation
 
@@ -109,8 +106,3 @@
 ;;;; working area
 
 (defvar *obj* nil)
-
-(defvar *trials* nil)
-
-(defun try (obj theta)
-  (push (make-instance 'trial :theta theta :loss (funcall obj theta)) *trials*))
diff --git a/test-decons.lisp b/test-decons.lisp
index ca52b5e..2e39246 100644
--- a/test-decons.lisp
+++ b/test-decons.lisp
@@ -68,8 +68,6 @@
     (setf objective (funcall (decons:l2-loss #'decons:line) *ds1*))
     (setf decons:*obj* objective)
     (== (funcall objective '(0.0 0.0)) 33.21)
-    (setf decons:*trials* nil)
-    (decons:try objective '(0.0 0.0))
-    (decons:try objective '(0.0099 0.0))
     (== (decons:nabla-xp objective '(0.0 0.0)) '(-62.999725 -21.0001))
+    (== (decons:gradient-descent objective '(0.0 0.0)) '(1.0499986 3.6358833e-6))
 ))