From e986572e9095c0f646ddee4ac03c487e586de0aa Mon Sep 17 00:00:00 2001
From: maderix <maderix@max.local>
Date: Wed, 4 Mar 2026 04:41:38 -0800
Subject: [PATCH] Replace assert() with non-fatal bounds checks on token IDs
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Follow-up to PR #31 — assert() aborts on bad tokens, which is too
harsh for training. Skip bad tokens with a warning instead.
---
 training/stories_cpu_ops.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/training/stories_cpu_ops.h b/training/stories_cpu_ops.h
index ae4dfdf..cd103c5 100644
--- a/training/stories_cpu_ops.h
+++ b/training/stories_cpu_ops.h
@@ -1,7 +1,7 @@
 // stories_cpu_ops.h — CPU operations: RMSNorm, cross-entropy, Adam, softmax
 #pragma once
 #include "stories_config.h"
-#include <assert.h>
+
 
 static void rmsnorm(float *out, const float *x, const float *w, int d, int S) {
     float *rms_tmp = (float*)malloc(S * sizeof(float));
@@ -95,7 +95,7 @@ static float cross_entropy_loss(float *dlogits, const float *logits, const uint1
         vDSP_vsmul(row, 1, &inv_sum, row, 1, (vDSP_Length)V);
         // loss
         int tgt = targets[t];
-        assert(tgt >= 0 && tgt < V && "target token ID out of vocab range");
+        if (tgt < 0 || tgt >= V) { fprintf(stderr, "WARN: target token %d out of vocab range [0,%d), skipping\n", tgt, V); continue; }
         total_loss -= logf(row[tgt] + 1e-10f);
         // gradient: softmax - one_hot, then /S
         row[tgt] -= 1.0f;
@@ -112,7 +112,7 @@ static float cross_entropy_loss(float *dlogits, const float *logits, const uint1
 static void embed_lookup(float *x, const float *embed, const uint16_t *tokens, int dim, int seq) {
     for (int t = 0; t < seq; t++) {
         int tok = tokens[t];
-        assert(tok >= 0 && tok < VOCAB && "token ID out of embedding range");
+        if (tok < 0 || tok >= VOCAB) { fprintf(stderr, "WARN: token %d out of range [0,%d)\n", tok, VOCAB); continue; }
         for (int d = 0; d < dim; d++) {
             x[d*seq + t] = embed[tok*dim + d];
         }
@@ -123,7 +123,7 @@ static void embed_lookup(float *x, const float *embed, const uint16_t *tokens, i
 static void embed_backward(float *d_embed, const float *dx, const uint16_t *tokens, int dim, int seq) {
     for (int t = 0; t < seq; t++) {
         int tok = tokens[t];
-        assert(tok >= 0 && tok < VOCAB && "token ID out of embedding range");
+        if (tok < 0 || tok >= VOCAB) { continue; }
         for (int d = 0; d < dim; d++) {
             d_embed[tok*dim + d] += dx[d*seq + t];
         }