From 0e9d3afd775c4ca466444e26908fd3f9291978b7 Mon Sep 17 00:00:00 2001
From: Laurent Mazare <laurent.mazare@gmail.com>
Date: Mon, 10 Jul 2023 23:22:58 +0100
Subject: [PATCH] Simplify the var-builder layer setup. (#133)

---
 .../examples/musicgen/encodec_model.rs        | 60 ++++++++-----------
 1 file changed, 24 insertions(+), 36 deletions(-)

diff --git a/candle-examples/examples/musicgen/encodec_model.rs b/candle-examples/examples/musicgen/encodec_model.rs
index 242c349c..ed8a66b7 100644
--- a/candle-examples/examples/musicgen/encodec_model.rs
+++ b/candle-examples/examples/musicgen/encodec_model.rs
@@ -262,22 +262,16 @@ struct EncodecResnetBlock {
 impl EncodecResnetBlock {
     fn load(dim: usize, dilations: &[usize], vb: VarBuilder, cfg: &Config) -> Result<Self> {
         let h = dim / cfg.compress;
-        let mut layer = Layer::new("block");
+        let mut layer = Layer::new(vb.pp("block"));
         if dilations.len() != 2 {
             anyhow::bail!("expected dilations of size 2")
         }
         // TODO: Apply dilations!
         layer.inc();
-        let block_conv1 = EncodecConv1d::load(
-            dim,
-            h,
-            cfg.residual_kernel_size,
-            1,
-            vb.pp(&layer.next_name()),
-            cfg,
-        )?;
+        let block_conv1 =
+            EncodecConv1d::load(dim, h, cfg.residual_kernel_size, 1, layer.next(), cfg)?;
         layer.inc();
-        let block_conv2 = EncodecConv1d::load(h, dim, 1, 1, vb.pp(&layer.next_name()), cfg)?;
+        let block_conv2 = EncodecConv1d::load(h, dim, 1, 1, layer.next(), cfg)?;
         let shortcut = if cfg.use_conv_shortcut {
             let conv = EncodecConv1d::load(dim, dim, 1, 1, vb.pp("shortcut"), cfg)?;
             Some(conv)
@@ -292,28 +286,24 @@ impl EncodecResnetBlock {
     }
 }
 
-#[derive(Debug)]
-struct Layer {
-    prefix: String,
+struct Layer<'a> {
+    vb: VarBuilder<'a>,
     cnt: usize,
 }
 
-impl Layer {
-    fn new(prefix: &str) -> Self {
-        Self {
-            prefix: prefix.to_string(),
-            cnt: 0,
-        }
+impl<'a> Layer<'a> {
+    fn new(vb: VarBuilder<'a>) -> Self {
+        Self { vb, cnt: 0 }
     }
 
     fn inc(&mut self) {
         self.cnt += 1;
     }
 
-    fn next_name(&mut self) -> String {
-        let name = format!("{}.{}", self.prefix, self.cnt);
+    fn next(&mut self) -> VarBuilder<'a> {
+        let vb = self.vb.pp(&self.cnt.to_string());
         self.cnt += 1;
-        name
+        vb
     }
 }
 
@@ -327,13 +317,13 @@ struct EncodecEncoder {
 
 impl EncodecEncoder {
     fn load(vb: VarBuilder, cfg: &Config) -> Result<Self> {
-        let mut layer = Layer::new("layers");
+        let mut layer = Layer::new(vb.pp("layers"));
         let init_conv = EncodecConv1d::load(
             cfg.audio_channels,
             cfg.num_filters,
             cfg.kernel_size,
             1,
-            vb.pp(&layer.next_name()),
+            layer.next(),
             cfg,
         )?;
         let mut sampling_layers = vec![];
@@ -345,7 +335,7 @@ impl EncodecEncoder {
                 let resnet = EncodecResnetBlock::load(
                     current_scale,
                     &[cfg.dilation_growth_rate.pow(j), 1],
-                    vb.pp(&layer.next_name()),
+                    layer.next(),
                     cfg,
                 )?;
                 resnets.push(resnet)
@@ -356,21 +346,20 @@ impl EncodecEncoder {
                 current_scale * 2,
                 ratio * 2,
                 ratio,
-                vb.pp(&layer.next_name()),
+                layer.next(),
                 cfg,
             )?;
             sampling_layers.push((resnets, conv1d));
             scaling *= 2;
         }
-        let final_lstm =
-            EncodecLSTM::load(cfg.num_filters * scaling, vb.pp(&layer.next_name()), cfg)?;
+        let final_lstm = EncodecLSTM::load(cfg.num_filters * scaling, layer.next(), cfg)?;
         layer.inc(); // ELU
         let final_conv = EncodecConv1d::load(
             cfg.num_filters * scaling,
             cfg.hidden_size,
             cfg.last_kernel_size,
             1,
-            vb.pp(&layer.next_name()),
+            layer.next(),
             cfg,
         )?;
         Ok(Self {
@@ -392,18 +381,17 @@ struct EncodecDecoder {
 
 impl EncodecDecoder {
     fn load(vb: VarBuilder, cfg: &Config) -> Result<Self> {
-        let mut layer = Layer::new("layers");
+        let mut layer = Layer::new(vb.pp("layers"));
         let mut scaling = usize::pow(2, cfg.upsampling_ratios.len() as u32);
         let init_conv = EncodecConv1d::load(
             cfg.hidden_size,
             cfg.num_filters * scaling,
             cfg.last_kernel_size,
             1,
-            vb.pp(&layer.next_name()),
+            layer.next(),
             cfg,
         )?;
-        let init_lstm =
-            EncodecLSTM::load(cfg.num_filters * scaling, vb.pp(&layer.next_name()), cfg)?;
+        let init_lstm = EncodecLSTM::load(cfg.num_filters * scaling, layer.next(), cfg)?;
         let mut sampling_layers = vec![];
         for &ratio in cfg.upsampling_ratios.iter() {
             let current_scale = scaling * cfg.num_filters;
@@ -413,7 +401,7 @@ impl EncodecDecoder {
                 current_scale / 2,
                 ratio * 2,
                 ratio,
-                vb.pp(&layer.next_name()),
+                layer.next(),
                 cfg,
             )?;
             let mut resnets = vec![];
@@ -421,7 +409,7 @@ impl EncodecDecoder {
                 let resnet = EncodecResnetBlock::load(
                     current_scale / 2,
                     &[cfg.dilation_growth_rate.pow(j), 1],
-                    vb.pp(&layer.next_name()),
+                    layer.next(),
                     cfg,
                 )?;
                 resnets.push(resnet)
@@ -435,7 +423,7 @@ impl EncodecDecoder {
             cfg.audio_channels,
             cfg.last_kernel_size,
             1,
-            vb.pp(&layer.next_name()),
+            layer.next(),
             cfg,
         )?;
         Ok(Self {