feat(kokoro): F16-quantize voice_tensors

Author: danielzgtg

src/kokoro_model.cpp

@@ -1,5 +1,7 @@
 #include "kokoro_model.h"
 
+#define ggml_cast_if_needed(ctx, x, qtype) (x->type == qtype ? x : ggml_cast(ctx, x, qtype))
+
 static struct ggml_tensor * build_albert_attn_mask(ggml_context * ctx, struct kokoro_duration_context *kctx, const kokoro_ubatch & batch) {
     kctx->attn_mask = ggml_new_tensor_2d(ctx, GGML_TYPE_F32, (int64_t) batch.n_tokens, (int64_t) batch.n_tokens);
     ggml_set_input(kctx->attn_mask);
@@ -943,7 +945,7 @@ struct ggml_cgraph * kokoro_duration_runner::build_kokoro_duration_graph(kokoro_
     // In order to side step this problem I computed the graph and determined the size in advance and use that constant value here.
     struct ggml_cgraph * gf = ggml_new_graph_custom(ctx, 110000, false);
 
-    struct ggml_tensor * voice = model->voices[kctx->voice];
+    struct ggml_tensor * voice = ggml_cast_if_needed(ctx, model->voices[kctx->voice], GGML_TYPE_F32);
     struct ggml_tensor * cur;
     struct ggml_tensor * inpL;
 
@@ -1146,7 +1148,7 @@ struct ggml_cgraph * kokoro_runner::build_kokoro_graph(kokoro_ubatch & batch) {
     // In order to side step this problem I computed the graph and determined the size in advance and use that constant value here.
     struct ggml_cgraph * gf = ggml_new_graph_custom(ctx, 570000, false);
 
-    struct ggml_tensor * voice = model->voices[kctx->voice];
+    struct ggml_tensor * voice = ggml_cast_if_needed(ctx, model->voices[kctx->voice], GGML_TYPE_F32);
     struct ggml_tensor * style_half = ggml_view_1d(ctx, voice, voice->ne[0]/2, voice->ne[0] / 2 * voice->nb[0] + (batch.n_tokens - 3) * voice->nb[1]);
     struct ggml_tensor * cur;
 

src/tts.cpp

@@ -191,8 +191,7 @@ void update_conditional_prompt(tts_runner * runner, const std::string file_path,
 }
 
 bool kokoro_is_f16_compatible(std::string name) {
-    return name.find("voice_tensors") == std::string::npos && 
-           name.find("bias") == std::string::npos &&
+    return name.find("bias") == std::string::npos &&
            name.find("gamma") == std::string::npos &&
            name.find("beta") == std::string::npos &&
            name.find("alpha") == std::string::npos &&