From 6183291906184569c2206c34588d118cc77f74bb Mon Sep 17 00:00:00 2001
From: =?utf8?q?Fran=C3=A7ois=20Fleuret?= <francois@fleuret.org>
Date: Sun, 7 Jan 2024 11:54:31 +0100
Subject: [PATCH] Update.

---
 main.py  | 13 ++++++++++++-
 mygpt.py | 19 +++++++++++--------
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/main.py b/main.py
index 18c0730..cae20f8 100755
--- a/main.py
+++ b/main.py
@@ -24,6 +24,17 @@ else:
 
 ######################################################################
 
+
+def str2bool(x):
+    x = x.lower()
+    if x in {"1", "true", "yes"}:
+        return True
+    elif x in {"0", "false", "no"}:
+        return False
+    else:
+        raise ValueError
+
+
 parser = argparse.ArgumentParser(
     description="An implementation of GPT with cache.",
     formatter_class=argparse.ArgumentDefaultsHelpFormatter,
@@ -68,7 +79,7 @@ parser.add_argument("--min_learning_rate", type=float, default=6e-5)
 
 # legacy
 
-parser.add_argument("--legacy_lr_schedule", action="store_true", default=False)
+parser.add_argument("--legacy_lr_schedule", type=str2bool, default=True)
 
 parser.add_argument("--legacy_large_lr", type=float, default=1e-4)
 
diff --git a/mygpt.py b/mygpt.py
index f97af49..f10f1fe 100755
--- a/mygpt.py
+++ b/mygpt.py
@@ -472,15 +472,18 @@ def flash_back_time_src(N, H, t0, t1, CL, CH, proba, device):
     fb_body = fb_body.cumsum(dim=2)
     fb_start = fb_start * (fb_body == 1)
 
-    # pick past starting source times
-    src_time = (
-        fb_start
+    # t_s = t0-(t0//L * R)*L
+
+    t = torch.arange(fb_start.size(2), device=fb_start.device)[None, None, :]
+    src_time = fb_start * (
+        t
+        - CL
         * (
-            torch.rand(fb_start.size(), device=fb_start.device)
-            * (torch.arange(fb_start.size(2), device=fb_start.device) - CL)[
-                None, None, :
-            ]
-        ).long()
+            1
+            + (
+                torch.rand(fb_start.size(), device=fb_start.device) * (t // CL - 1)
+            ).long()
+        )
     )
     src_time[:, :, CL:] -= src_time.clone()[:, :, :-CL]
     src_time = src_time.cumsum(dim=2)
-- 
2.20.1