ggml : require mask when using ALiBi

ggml-ci

Author: ggerganov

ggml.c

@@ -5657,6 +5657,10 @@ static struct ggml_tensor * ggml_soft_max_impl(
         GGML_ASSERT(mask->ne[1] >= a->ne[1]);
     }
 
+    if (max_bias > 0.0f) {
+        GGML_ASSERT(mask);
+    }
+
     bool is_node = false;
 
     if (a->grad) {
@@ -6440,6 +6444,7 @@ struct ggml_tensor * ggml_flash_attn_ext(
         float                 max_bias) {
     GGML_ASSERT(ggml_can_mul_mat(k, q));
     // TODO: check if vT can be multiplied by (k*qT)
+
     if (mask) {
         GGML_ASSERT(ggml_is_contiguous(mask));
         GGML_ASSERT(mask->ne[2] == 1);
@@ -6449,6 +6454,10 @@ struct ggml_tensor * ggml_flash_attn_ext(
         //GGML_ASSERT(ggml_can_repeat_rows(mask, qk));
     }
 
+    if (max_bias > 0.0f) {
+        GGML_ASSERT(mask);
+    }
+
     bool is_node = false;
 
     if (q->grad || k->grad || v->grad) {

tests/test-backend-ops.cpp

@@ -2126,6 +2126,7 @@ static bool test_backend(ggml_backend_t backend, test_mode mode, const char * op
 #endif
     for (bool mask : {false, true}) {
         for (float max_bias : {0.0f, 8.0f}) {
+            if (!mask && max_bias > 0.0f) continue;
             for (float scale : {1.0f, 0.1f}) {
                 for (int64_t ne0 : {16, 1024}) {
                     for (int64_t ne1 : {16, 1024}) {
@@ -2139,7 +2140,6 @@ static bool test_backend(ggml_backend_t backend, test_mode mode, const char * op
 
     test_cases.emplace_back(new test_soft_max(GGML_TYPE_F32, {16, 2, 32, 1}, false, 0.1f, 0.0f));
     test_cases.emplace_back(new test_soft_max(GGML_TYPE_F32, {32, 2, 32, 1}, true,  0.1f, 0.0f));
-    test_cases.emplace_back(new test_soft_max(GGML_TYPE_F32, {16, 2, 32, 1}, false, 0.1f, 8.0f));
     test_cases.emplace_back(new test_soft_max(GGML_TYPE_F32, {32, 2, 32, 1}, true,  0.1f, 8.0f));
 
     for (ggml_type type : {GGML_TYPE_F32, GGML_TYPE_F16}) {