hparam comparison uses memcpy for floating point comparison, which is in general a bad idea

llama.cpp

@@ -123,6 +123,28 @@ static void replace_all(std::string & s, const std::string & search, const std::
     }
     s = std::move(result);
 }
+
+bool is_float_eq(float a, float b, float abs_tol) {
+    // Check for non-negative tolerance
+    if (abs_tol < 0.0) {
+        throw std::invalid_argument("Tolerance must be non-negative");
+    }
+
+    // Exact equality check
+    if (a == b) {
+        return true;
+    }
+
+    // Check for infinities
+    if (std::isinf(a) || std::isinf(b)) {
+        return false;
+    }
+
+    // Regular comparison using the provided absolute tolerance
+    double diff = std::fabs(b - a);
+    return (diff <= abs_tol);
+}
+
 #ifdef GGML_USE_CPU_HBM
 #include <hbwmalloc.h>
 #endif
@@ -947,8 +969,30 @@ struct llama_hparams {
     float rope_freq_base_train;
     float rope_freq_scale_train;
 
+    bool operator==(const llama_hparams & other) const {
+        if (this->vocab_only != other.vocab_only) return false;
+        if (this->n_vocab != other.n_vocab) return false;
+        if (this->n_ctx_train != other.n_ctx_train) return false;
+        if (this->n_embd != other.n_embd) return false;
+        if (this->n_head != other.n_head) return false;
+        if (this->n_head_kv != other.n_head_kv) return false;
+        if (this->n_layer != other.n_layer) return false;
+        if (this->n_rot != other.n_rot) return false;
+        if (this->n_ff != other.n_ff) return false;
+
+        const float EPSILON = 1e-9;
+
+        if (!is_float_eq(this->f_norm_eps, other.f_norm_eps, EPSILON)) return false;
+        if (!is_float_eq(this->f_norm_rms_eps, other.f_norm_rms_eps, EPSILON)) return false;
+        if (!is_float_eq(this->rope_freq_base_train, other.rope_freq_base_train, EPSILON)) return false;
+        if (!is_float_eq(this->rope_freq_scale_train, other.rope_freq_scale_train, EPSILON)) return false;
+
+        return true;
+    }
+
+    // implement != explicitly using the "==" implementation above so we don't get a warning about it
     bool operator!=(const llama_hparams & other) const {
-        return static_cast<bool>(memcmp(this, &other, sizeof(llama_hparams))); // NOLINT
+        return !(*this == other);
     }
 
     uint32_t n_gqa() const {