Merge branch 'main' into upgrade_bert

15 files changed, 1228 insertions, 2 deletions

diff --git a/candle-core/src/backprop.rs b/candle-core/src/backprop.rs
index 45448505..a44f732f 100644
--- a/candle-core/src/backprop.rs
+++ b/candle-core/src/backprop.rs
@@ -33,7 +33,12 @@ impl Tensor {
                         track_grad |= tg;
                         nodes
                     }
-                    Op::Add(lhs, rhs)
+                    Op::Conv1D {
+                        arg: lhs,
+                        kernel: rhs,
+                        ..
+                    }
+                    | Op::Add(lhs, rhs)
                     | Op::Mul(lhs, rhs)
                     | Op::Sub(lhs, rhs)
                     | Op::Div(lhs, rhs)
@@ -147,6 +152,7 @@ impl Tensor {
                         let f_grad = pred.where_cond(&zeros, &grad)?;
                         *f_sum_grad = f_sum_grad.add(&f_grad)?;
                     }
+                    Op::Conv1D { .. } => return Err(Error::BackwardNotSupported { op: "conv1d" }),
                     Op::Embedding(_lhs, _rhs) => {
                         return Err(Error::BackwardNotSupported { op: "embedding" })
                     }
diff --git a/candle-core/src/conv.rs b/candle-core/src/conv.rs
new file mode 100644
index 00000000..041bb6fb
--- /dev/null
+++ b/candle-core/src/conv.rs
@@ -0,0 +1,27 @@
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub(crate) struct ParamsConv1D {
+    pub(crate) b_size: Option<usize>,
+    // Maybe we should have a version without l_in as this bit depends on the input and not only on
+    // the weights.
+    pub(crate) l_in: usize,
+    pub(crate) c_out: usize,
+    pub(crate) c_in: usize,
+    pub(crate) k_size: usize,
+    pub(crate) padding: usize,
+    pub(crate) stride: usize,
+}
+
+impl ParamsConv1D {
+    pub(crate) fn l_out(&self) -> usize {
+        let dilation = 1;
+        (self.l_in + 2 * self.padding - dilation * (self.k_size - 1) - 1) / self.stride + 1
+    }
+
+    pub(crate) fn out_dims(&self) -> Vec<usize> {
+        let l_out = self.l_out();
+        match self.b_size {
+            None => vec![self.c_out, l_out],
+            Some(n) => vec![n, self.c_out, l_out],
+        }
+    }
+}
diff --git a/candle-core/src/cpu_backend.rs b/candle-core/src/cpu_backend.rs
index 0871175f..b2345756 100644
--- a/candle-core/src/cpu_backend.rs
+++ b/candle-core/src/cpu_backend.rs
@@ -202,6 +202,64 @@ fn copy_strided_src_<T: Copy + std::fmt::Display>(
     }
 }
 
+struct Conv1D<'a>(&'a crate::conv::ParamsConv1D);
+
+impl<'a> Map2 for Conv1D<'a> {
+    const OP: &'static str = "conv1d";
+    fn f<T: 'static + num_traits::NumAssign + Copy>(
+        &self,
+        inp: &[T],
+        inp_l: &Layout,
+        k: &[T],
+        k_l: &Layout,
+    ) -> Result<Vec<T>> {
+        // TODO: Optimize this (proper algorithm, simd, multithread, remove bound checks, etc).
+        let p = self.0;
+        let inp = &inp[inp_l.start_offset()..];
+        let k = &k[k_l.start_offset()..];
+        let inp_stride = inp_l.stride();
+        let (inp_stride0, inp_stride) = if inp_stride.len() == 3 {
+            (inp_stride[0], &inp_stride[1..])
+        } else {
+            (0, inp_stride) // This value never gets used anyway
+        };
+        let k_stride = k_l.stride();
+        let k_over_2 = p.k_size / 2;
+        let l_out = p.l_out();
+        let dst_elems = p.c_out * l_out * p.b_size.unwrap_or(1);
+        let mut dst = vec![T::zero(); dst_elems];
+        // The output shape is [b_size, c_out, l_out]
+        for b_idx in 0..p.b_size.unwrap_or(1) {
+            let inp_idx = b_idx * inp_stride0;
+            let dst_idx = b_idx * p.c_out * l_out;
+            for dst_c_idx in 0..p.c_out {
+                let dst_idx = dst_idx + dst_c_idx * l_out;
+                for dst_l in 0..l_out {
+                    let dst_idx = dst_idx + dst_l;
+                    let mut d = T::zero();
+                    for offset in 0..p.k_size {
+                        let src_l_plus = p.stride * dst_l + offset;
+                        // inp[bidx, src_c_idx, dst_l + offset - k//2] * k[dst_c_idx, src_c_idx, offset]
+                        if k_over_2 <= src_l_plus && src_l_plus < k_over_2 + p.l_in {
+                            let src_l = src_l_plus - k_over_2;
+                            for src_c_idx in 0..p.c_in {
+                                let inp_idx =
+                                    inp_idx + src_c_idx * inp_stride[0] + src_l * inp_stride[1];
+                                let k_idx = dst_c_idx * k_stride[0]
+                                    + src_c_idx * k_stride[1]
+                                    + offset * k_stride[2];
+                                d += inp[inp_idx] * k[k_idx]
+                            }
+                        }
+                    }
+                    dst[dst_idx] = d
+                }
+            }
+        }
+        Ok(dst)
+    }
+}
+
 struct MatMul((usize, usize, usize, usize));
 
 impl Map2 for MatMul {
@@ -627,6 +685,16 @@ impl CpuStorage {
         WCond(pred, layout).map(t, t_l, f, f_l)
     }
 
+    pub(crate) fn conv1d(
+        &self,
+        l: &Layout,
+        kernel: &Self,
+        kernel_l: &Layout,
+        params: &crate::conv::ParamsConv1D,
+    ) -> Result<Self> {
+        Conv1D(params).map(self, l, kernel, kernel_l)
+    }
+
     pub(crate) fn embedding(&self, ids_l: &Layout, rhs: &Self, rhs_l: &Layout) -> Result<Self> {
         let ids = self.as_slice::<u32>()?;
         let (vocab_size, hidden_size) = rhs_l.shape().r2()?;
diff --git a/candle-core/src/cuda_backend.rs b/candle-core/src/cuda_backend.rs
index 0c87004b..917655fc 100644
--- a/candle-core/src/cuda_backend.rs
+++ b/candle-core/src/cuda_backend.rs
@@ -801,6 +801,16 @@ impl CudaStorage {
         Ok(Self { slice, device })
     }
 
+    pub(crate) fn conv1d(
+        &self,
+        _l: &Layout,
+        _kernel: &Self,
+        _kernel_l: &Layout,
+        _params: &crate::conv::ParamsConv1D,
+    ) -> Result<Self> {
+        todo!()
+    }
+
     pub(crate) fn embedding(&self, layout: &Layout, rhs: &Self, rhs_l: &Layout) -> Result<Self> {
         let device = self.device().clone();
         let slice = Embedding(self, layout).map(&rhs.slice, &device, rhs_l)?;
diff --git a/candle-core/src/dummy_cuda_backend.rs b/candle-core/src/dummy_cuda_backend.rs
index b025eeab..0dbd8d54 100644
--- a/candle-core/src/dummy_cuda_backend.rs
+++ b/candle-core/src/dummy_cuda_backend.rs
@@ -100,6 +100,16 @@ impl CudaStorage {
         Err(Error::NotCompiledWithCudaSupport)
     }
 
+    pub(crate) fn conv1d(
+        &self,
+        _l: &Layout,
+        _kernel: &Self,
+        _kernel_l: &Layout,
+        _params: &crate::conv::ParamsConv1D,
+    ) -> Result<Self> {
+        Err(Error::NotCompiledWithCudaSupport)
+    }
+
     pub(crate) fn embedding(&self, _: &Layout, _: &Self, _: &Layout) -> Result<Self> {
         Err(Error::NotCompiledWithCudaSupport)
     }
diff --git a/candle-core/src/lib.rs b/candle-core/src/lib.rs
index 0d4c2a8d..2365a34d 100644
--- a/candle-core/src/lib.rs
+++ b/candle-core/src/lib.rs
@@ -1,4 +1,5 @@
 mod backprop;
+mod conv;
 mod cpu_backend;
 #[cfg(feature = "cuda")]
 mod cuda_backend;
diff --git a/candle-core/src/op.rs b/candle-core/src/op.rs
index 860be0b3..ee57b325 100644
--- a/candle-core/src/op.rs
+++ b/candle-core/src/op.rs
@@ -12,6 +12,14 @@ pub(crate) enum Op {
     Embedding(Tensor, Tensor),
     WhereCond(Tensor, Tensor, Tensor),
 
+    #[allow(dead_code)]
+    Conv1D {
+        arg: Tensor,
+        kernel: Tensor,
+        padding: usize,
+        stride: usize,
+    },
+
     Cat(Vec<Tensor>, usize),
 
     #[allow(dead_code)] // add is currently unused.
diff --git a/candle-core/src/storage.rs b/candle-core/src/storage.rs
index 4e630a58..53ea1544 100644
--- a/candle-core/src/storage.rs
+++ b/candle-core/src/storage.rs
@@ -144,6 +144,32 @@ impl Storage {
         }
     }
 
+    pub(crate) fn conv1d(
+        &self,
+        l: &Layout,
+        kernel: &Self,
+        kernel_l: &Layout,
+        params: &crate::conv::ParamsConv1D,
+    ) -> Result<Self> {
+        self.same_device(kernel, "conv1d")?;
+        self.same_dtype(kernel, "conv1d")?;
+        match (self, &kernel) {
+            (Storage::Cpu(inp), Storage::Cpu(kernel)) => {
+                let s = inp.conv1d(l, kernel, kernel_l, params)?;
+                Ok(Self::Cpu(s))
+            }
+            (Storage::Cuda(inp), Storage::Cuda(kernel)) => {
+                let s = inp.conv1d(l, kernel, kernel_l, params)?;
+                Ok(Self::Cuda(s))
+            }
+            (lhs, rhs) => Err(Error::DeviceMismatchBinaryOp {
+                lhs: lhs.device().location(),
+                rhs: rhs.device().location(),
+                op: "conv1d",
+            }),
+        }
+    }
+
     pub(crate) fn where_cond(
         &self,
         layout: &Layout,
diff --git a/candle-core/src/tensor.rs b/candle-core/src/tensor.rs
index a468d879..95f663f0 100644
--- a/candle-core/src/tensor.rs
+++ b/candle-core/src/tensor.rs
@@ -326,7 +326,7 @@ impl Tensor {
         }
         let from_cpu_storage = |cpu_storage: &crate::CpuStorage| {
             let data = S::cpu_storage_as_slice(cpu_storage)?;
-            Ok::<_, Error>(data[0])
+            Ok::<_, Error>(data[self.layout().start_offset()])
         };
         match self.storage.as_ref() {
             Storage::Cpu(cpu_storage) => from_cpu_storage(cpu_storage),
@@ -432,6 +432,42 @@ impl Tensor {
         Ok(from_storage(storage, dims, op, false))
     }
 
+    pub fn conv1d(&self, kernel: &Self, padding: usize, stride: usize) -> Result<Self> {
+        let (c_out, c_in_k, k_size) = kernel.shape().r3()?;
+        let (b_size, c_in, l_in) = match *self.dims() {
+            [b_size, c_in, l_in] => (Some(b_size), c_in, l_in),
+            [c_in, l_in] => (None, c_in, l_in),
+            _ => todo!("proper error message"),
+        };
+        if c_in != c_in_k {
+            todo!("proper error message")
+        }
+        let params = crate::conv::ParamsConv1D {
+            b_size,
+            l_in,
+            c_out,
+            c_in,
+            k_size,
+            padding,
+            stride,
+        };
+        let storage =
+            self.storage
+                .conv1d(self.layout(), &kernel.storage, kernel.layout(), &params)?;
+        let op = if self.track_op() || kernel.track_op() {
+            Some(Op::Conv1D {
+                arg: self.clone(),
+                kernel: kernel.clone(),
+                padding,
+                stride,
+            })
+        } else {
+            None
+        };
+        let out_dims = params.out_dims();
+        Ok(from_storage(storage, out_dims, op, false))
+    }
+
     pub fn matmul(&self, rhs: &Self) -> Result<Self> {
         let a_dims = self.shape().dims();
         let b_dims = rhs.shape().dims();
diff --git a/candle-examples/Cargo.toml b/candle-examples/Cargo.toml
index 53a1a150..a39ee3a3 100644
--- a/candle-examples/Cargo.toml
+++ b/candle-examples/Cargo.toml
@@ -14,6 +14,7 @@ readme = "README.md"
 candle = { path = "../candle-core", default-features=false }
 serde = { version = "1.0.166", features = ["derive"] }
 serde_json = "1.0.99"
+num-traits = "0.2.15"
 
 [dev-dependencies]
 anyhow = { version = "1", features = ["backtrace"] }
@@ -22,6 +23,7 @@ clap = { version = "4.2.4", features = ["derive"] }
 rand = "0.8.5"
 tokenizers = { version = "0.13.3", default-features=false, features=["onig"] }
 tokio = { version = "1.28.2", features = ["macros", "rt-multi-thread"] }
+wav = "1.0.0"
 
 [features]
 default = ["cuda"]
diff --git a/candle-examples/examples/whisper/audio.rs b/candle-examples/examples/whisper/audio.rs
new file mode 100644
index 00000000..d095e239
--- /dev/null
+++ b/candle-examples/examples/whisper/audio.rs
@@ -0,0 +1,216 @@
+// Audio processing code, adapted from whisper.cpp
+// https://github.com/ggerganov/whisper.cpp
+
+pub trait Float: num_traits::Float + num_traits::FloatConst + num_traits::NumAssign {}
+
+impl Float for f32 {}
+impl Float for f64 {}
+
+// https://github.com/ggerganov/whisper.cpp/blob/4774d2feb01a772a15de81ffc34b34a1f294f020/whisper.cpp#L2357
+fn fft<T: Float>(inp: &[T]) -> Vec<T> {
+    let n = inp.len();
+    let zero = T::zero();
+    if n == 1 {
+        return vec![inp[0], zero];
+    }
+    if n % 2 == 1 {
+        return dft(inp);
+    }
+    let mut out = vec![zero; n * 2];
+
+    let mut even = vec![];
+    even.reserve(n / 2);
+    let mut odd = vec![];
+    odd.reserve(n / 2);
+
+    for (i, &inp) in inp.iter().enumerate() {
+        if i % 2 == 0 {
+            even.push(inp)
+        } else {
+            odd.push(inp);
+        }
+    }
+
+    let even_fft = fft(&even);
+    let odd_fft = fft(&odd);
+
+    let two_pi = T::PI() + T::PI();
+    let n_t = T::from(n).unwrap();
+    for k in 0..n / 2 {
+        let k_t = T::from(k).unwrap();
+        let theta = two_pi * k_t / n_t;
+        let re = theta.cos();
+        let im = -theta.sin();
+
+        let re_odd = odd_fft[2 * k];
+        let im_odd = odd_fft[2 * k + 1];
+
+        out[2 * k] = even_fft[2 * k] + re * re_odd - im * im_odd;
+        out[2 * k + 1] = even_fft[2 * k + 1] + re * im_odd + im * re_odd;
+
+        out[2 * (k + n / 2)] = even_fft[2 * k] - re * re_odd + im * im_odd;
+        out[2 * (k + n / 2) + 1] = even_fft[2 * k + 1] - re * im_odd - im * re_odd;
+    }
+    out
+}
+
+// https://github.com/ggerganov/whisper.cpp/blob/4774d2feb01a772a15de81ffc34b34a1f294f020/whisper.cpp#L2337
+fn dft<T: Float>(inp: &[T]) -> Vec<T> {
+    let zero = T::zero();
+    let n = inp.len();
+    let two_pi = T::PI() + T::PI();
+
+    let mut out = Vec::new();
+    out.reserve(2 * n);
+    let n_t = T::from(n).unwrap();
+    for k in 0..n {
+        let k_t = T::from(k).unwrap();
+        let mut re = zero;
+        let mut im = zero;
+
+        for (j, &inp) in inp.iter().enumerate() {
+            let j_t = T::from(j).unwrap();
+            let angle = two_pi * k_t * j_t / n_t;
+            re += inp * angle.cos();
+            im -= inp * angle.sin();
+        }
+
+        out.push(re);
+        out.push(im);
+    }
+    out
+}
+
+#[allow(clippy::too_many_arguments)]
+// https://github.com/ggerganov/whisper.cpp/blob/4774d2feb01a772a15de81ffc34b34a1f294f020/whisper.cpp#L2414
+fn log_mel_spectrogram_w<T: Float>(
+    ith: usize,
+    hann: &[T],
+    samples: &[T],
+    filters: &[T],
+    fft_size: usize,
+    fft_step: usize,
+    speed_up: bool,
+    n_len: usize,
+    n_mel: usize,
+    n_threads: usize,
+) -> Vec<T> {
+    let n_fft = if speed_up {
+        1 + fft_size / 4
+    } else {
+        1 + fft_size / 2
+    };
+
+    let zero = T::zero();
+    let half = T::from(0.5).unwrap();
+    let mut fft_in = vec![zero; fft_size];
+    let mut mel = vec![zero; n_len * n_mel];
+
+    for i in (ith..n_len).step_by(n_threads) {
+        let offset = i * fft_step;
+
+        // apply Hanning window
+        for j in 0..fft_size {
+            fft_in[j] = if offset + j < samples.len() {
+                hann[j] * samples[offset + j]
+            } else {
+                zero
+            }
+        }
+
+        // FFT -> mag^2
+        let mut fft_out: Vec<T> = fft(&fft_in);
+
+        for j in 0..fft_size {
+            fft_out[j] = fft_out[2 * j] * fft_out[2 * j] + fft_out[2 * j + 1] * fft_out[2 * j + 1];
+        }
+        for j in 1..fft_size / 2 {
+            let v = fft_out[fft_size - j];
+            fft_out[j] += v;
+        }
+
+        if speed_up {
+            // scale down in the frequency domain results in a speed up in the time domain
+            for j in 0..n_fft {
+                fft_out[j] = half * (fft_out[2 * j] + fft_out[2 * j + 1]);
+            }
+        }
+
+        // mel spectrogram
+        for j in 0..n_mel {
+            let mut sum = zero;
+            for k in 0..n_fft {
+                sum += fft_out[k] * filters[j * n_fft + k];
+            }
+            mel[j * n_len + i] = T::max(sum, T::from(1e-10).unwrap()).log10();
+        }
+    }
+    mel
+}
+
+fn log_mel_spectrogram_<T: Float + std::fmt::Display>(
+    samples: &[T],
+    filters: &[T],
+    fft_size: usize,
+    fft_step: usize,
+    n_mel: usize,
+    speed_up: bool,
+) -> Vec<T> {
+    let zero = T::zero();
+    let two_pi = T::PI() + T::PI();
+    let half = T::from(0.5).unwrap();
+    let one = T::from(1.0).unwrap();
+    let four = T::from(4.0).unwrap();
+    let fft_size_t = T::from(fft_size).unwrap();
+
+    let hann: Vec<T> = (0..fft_size)
+        .map(|i| half * (one - ((two_pi * T::from(i).unwrap()) / fft_size_t).cos()))
+        .collect();
+    let n_len = samples.len() / fft_step;
+
+    // pad audio with at least one extra chunk of zeros
+    let pad = 100 * super::CHUNK_LENGTH / 2;
+    let n_len = if n_len % pad != 0 {
+        (n_len / pad + 1) * pad
+    } else {
+        n_len
+    };
+    let n_len = n_len + pad;
+    let samples = {
+        let mut samples_padded = samples.to_vec();
+        let to_add = n_len * fft_step - samples.len();
+        samples_padded.extend(std::iter::repeat(zero).take(to_add));
+        samples_padded
+    };
+
+    // Use a single thread for now.
+    let mut mel = log_mel_spectrogram_w(
+        0, &hann, &samples, filters, fft_size, fft_step, speed_up, n_len, n_mel, 1,
+    );
+    let mmax = mel
+        .iter()
+        .max_by(|&u, &v| u.partial_cmp(v).unwrap_or(std::cmp::Ordering::Greater))
+        .copied()
+        .unwrap_or(zero)
+        - T::from(8).unwrap();
+    for m in mel.iter_mut() {
+        let v = T::max(*m, mmax);
+        *m = v / four + one
+    }
+    mel
+}
+
+pub fn pcm_to_mel<T: Float + std::fmt::Display>(
+    samples: &[T],
+    filters: &[T],
+) -> anyhow::Result<Vec<T>> {
+    let mel = log_mel_spectrogram_(
+        samples,
+        filters,
+        super::N_FFT,
+        super::HOP_LENGTH,
+        super::N_MELS,
+        false,
+    );
+    Ok(mel)
+}
diff --git a/candle-examples/examples/whisper/extract_weights.py b/candle-examples/examples/whisper/extract_weights.py
new file mode 100644
index 00000000..65602703
--- /dev/null
+++ b/candle-examples/examples/whisper/extract_weights.py
@@ -0,0 +1,13 @@
+# Get the checkpoint from
+# https://openaipublic.azureedge.net/main/whisper/models/d3dd57d32accea0b295c96e26691aa14d8822fac7d9d27d5dc00b4ca2826dd03/tiny.en.pt
+
+import torch
+from safetensors.torch import save_file
+
+data = torch.load("tiny.en.pt")
+weights = {}
+for k, v in data["model_state_dict"].items():
+    weights[k] = v.contiguous()
+    print(k, v.shape, v.dtype)
+save_file(weights, "tiny.en.safetensors")
+print(data["dims"])
diff --git a/candle-examples/examples/whisper/main.rs b/candle-examples/examples/whisper/main.rs
new file mode 100644
index 00000000..6ea3e536
--- /dev/null
+++ b/candle-examples/examples/whisper/main.rs
@@ -0,0 +1,256 @@
+#![allow(dead_code)]
+// https://github.com/openai/whisper/blob/main/whisper/model.py
+// TODO:
+// - kv-cache support?
+// - Language detection?
+// - Batch size greater than 1.
+
+use anyhow::{Error as E, Result};
+use candle::{DType, Device, Tensor};
+use clap::Parser;
+use rand::{distributions::Distribution, SeedableRng};
+use tokenizers::Tokenizer;
+
+mod audio;
+mod model;
+use model::{Config, VarBuilder, Whisper};
+
+const DTYPE: DType = DType::F32;
+
+// Audio parameters.
+const SAMPLE_RATE: usize = 16000;
+const N_FFT: usize = 400;
+const N_MELS: usize = 80;
+const HOP_LENGTH: usize = 160;
+const CHUNK_LENGTH: usize = 30;
+const N_SAMPLES: usize = CHUNK_LENGTH * SAMPLE_RATE; // 480000 samples in a 30-second chunk
+const N_FRAMES: usize = N_SAMPLES / HOP_LENGTH; // 3000 frames in a mel spectrogram input
+const N_SAMPLES_PER_TOKEN: usize = HOP_LENGTH * 2; // the initial convolutions has stride 2
+const FRAMES_PER_SECOND: usize = SAMPLE_RATE / HOP_LENGTH; // 10ms per audio frame
+const TOKENS_PER_SECOND: usize = SAMPLE_RATE / N_SAMPLES_PER_TOKEN; // 20ms per audio token
+
+const NO_SPEECH_THRESHOLD: f64 = 0.6;
+const LOGPROB_THRESHOLD: f64 = -1.0;
+const TEMPERATURES: [f64; 6] = [0.0, 0.2, 0.4, 0.6, 0.8, 1.0];
+const COMPRESSION_RATIO_THRESHOLD: f64 = 2.4;
+
+// Tokenizer dependent bits.
+const SOT_TOKEN: u32 = 50257;
+const EOT_TOKEN: u32 = 50256;
+const NO_SPEECH_TOKEN: u32 = 50361;
+const NO_TIMESTAMP_TOKEN: u32 = 50362;
+
+#[derive(Debug, Clone)]
+struct DecodingResult {
+    tokens: Vec<u32>,
+    text: String,
+    avg_logprob: f64,
+    no_speech_prob: f64,
+    temperature: f64,
+    compression_ratio: f64,
+}
+
+#[derive(Debug, Clone)]
+struct Segment {
+    start: f64,
+    duration: f64,
+    dr: DecodingResult,
+}
+
+struct Decode {
+    model: Whisper,
+    rng: rand::rngs::StdRng,
+    tokenizer: Tokenizer,
+}
+
+impl Decode {
+    fn decode(&mut self, mel: &Tensor, t: f64) -> Result<DecodingResult> {
+        let model = &self.model;
+        let audio_features = model.encoder.forward(mel)?;
+        println!("audio features: {:?}", audio_features.dims());
+        let sample_len = model.config.n_text_ctx / 2;
+        let mut sum_logprob = 0f64;
+        let mut no_speech_prob = f64::NAN;
+        let mut tokens = vec![SOT_TOKEN];
+        for i in 0..sample_len {
+            let tokens_t = Tensor::new(tokens.as_slice(), &mel.device())?;
+
+            // The model expects a batch dim but this inference loop does not handle
+            // it so we add it at this point.
+            let tokens_t = tokens_t.unsqueeze(0)?;
+            let logits = model.decoder.forward(&tokens_t, &audio_features)?;
+            let logits = logits.squeeze(0)?;
+
+            // Extract the no speech probability on the first iteration by looking at the first
+            // token logits and the probability for the according token.
+            if i == 0 {
+                no_speech_prob = logits
+                    .get(0)?
+                    .softmax(0)?
+                    .get(NO_SPEECH_TOKEN as usize)?
+                    .to_scalar::<f32>()? as f64;
+            }
+
+            let (seq_len, _) = logits.shape().r2()?;
+            let logits = logits.get(seq_len - 1)?;
+            let next_token = if t > 0f64 {
+                let prs = (&logits / t)?.softmax(0)?;
+                let logits_v: Vec<f32> = prs.to_vec1()?;
+                let distr = rand::distributions::WeightedIndex::new(&logits_v)?;
+                distr.sample(&mut self.rng) as u32
+            } else {
+                let logits_v: Vec<f32> = logits.to_vec1()?;
+                logits_v
+                    .iter()
+                    .enumerate()
+                    .max_by(|(_, u), (_, v)| u.total_cmp(v))
+                    .map(|(i, _)| i as u32)
+                    .unwrap()
+            };
+            tokens.push(next_token);
+            let prob = logits
+                .softmax(logits.rank() - 1)?
+                .get(next_token as usize)?
+                .to_scalar::<f32>()? as f64;
+            if next_token == EOT_TOKEN || tokens.len() > model.config.n_text_ctx {
+                break;
+            }
+            sum_logprob += prob.ln();
+        }
+        let text = self
+            .tokenizer
+            .decode(tokens.clone(), true)
+            .map_err(E::msg)?;
+        let avg_logprob = sum_logprob / tokens.len() as f64;
+
+        Ok(DecodingResult {
+            tokens,
+            text,
+            avg_logprob,
+            no_speech_prob,
+            temperature: t,
+            compression_ratio: f64::NAN,
+        })
+    }
+
+    fn decode_with_fallback(&mut self, segment: &Tensor) -> Result<DecodingResult> {
+        for (i, &t) in TEMPERATURES.iter().enumerate() {
+            let dr: Result<DecodingResult> = self.decode(segment, t);
+            if i == TEMPERATURES.len() - 1 {
+                return dr;
+            }
+            // On errors, we try again with a different temperature.
+            match dr {
+                Ok(dr) => {
+                    let needs_fallback = dr.compression_ratio > COMPRESSION_RATIO_THRESHOLD
+                        || dr.avg_logprob < LOGPROB_THRESHOLD;
+                    if !needs_fallback || dr.no_speech_prob > NO_SPEECH_THRESHOLD {
+                        return Ok(dr);
+                    }
+                }
+                Err(err) => {
+                    println!("Error running at {t}: {err}")
+                }
+            }
+        }
+        unreachable!()
+    }
+}
+
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+struct Args {
+    /// Run on CPU rather than on GPU.
+    #[arg(long)]
+    cpu: bool,
+
+    #[arg(long)]
+    weights: String,
+
+    /// The input to be processed, in wav formats.
+    #[arg(long)]
+    input: String,
+
+    #[arg(long)]
+    tokenizer_config: String,
+
+    /// The seed to use when generating random samples.
+    #[arg(long, default_value_t = 299792458)]
+    seed: u64,
+
+    /// The mel filters in safetensors format.
+    #[arg(
+        long,
+        default_value = "candle-examples/examples/whisper/mel_filters.safetensors"
+    )]
+    filters: String,
+}
+
+fn main() -> Result<()> {
+    let args = Args::parse();
+    let device = if args.cpu {
+        Device::Cpu
+    } else {
+        Device::new_cuda(0)?
+    };
+    let rng = rand::rngs::StdRng::seed_from_u64(args.seed);
+
+    let tokenizer = Tokenizer::from_file(args.tokenizer_config).map_err(E::msg)?;
+
+    let mel_filters = unsafe { candle::safetensors::MmapedFile::new(args.filters)? };
+    let mel_filters = mel_filters.deserialize()?;
+    let mel_filters = mel_filters.tensor("mel_80", &device)?;
+    println!("loaded mel filters {:?}", mel_filters.shape());
+    let mel_filters = mel_filters.flatten_all()?.to_vec1::<f32>()?;
+
+    let mut input = std::fs::File::open(args.input)?;
+    let (header, data) = wav::read(&mut input)?;
+    println!("loaded wav data: {header:?}");
+    if header.sampling_rate != SAMPLE_RATE as u32 {
+        anyhow::bail!("wav file must have a {} sampling rate", SAMPLE_RATE)
+    }
+    let data = data.as_sixteen().expect("expected 16 bit wav file");
+    let pcm_data: Vec<_> = data[..data.len() / header.channel_count as usize]
+        .iter()
+        .map(|v| *v as f32 / 32768.)
+        .collect();
+    println!("pcm data loaded {}", pcm_data.len());
+    let mel = audio::pcm_to_mel(&pcm_data, &mel_filters)?;
+    let mel_len = mel.len();
+    let mel = Tensor::from_vec(mel, (1, N_MELS, mel_len / N_MELS), &device)?;
+    println!("loaded mel: {:?}", mel.dims());
+
+    let weights = unsafe { candle::safetensors::MmapedFile::new(args.weights)? };
+    let weights = weights.deserialize()?;
+    let vb = VarBuilder::from_safetensors(vec![weights], DTYPE, device);
+    let model = Whisper::load(&vb, Config::tiny_en())?;
+    let mut dc = Decode {
+        model,
+        rng,
+        tokenizer,
+    };
+
+    let (_, _, content_frames) = mel.shape().r3()?;
+    let mut seek = 0;
+    let mut segments = vec![];
+    while seek < content_frames {
+        let time_offset = (seek * HOP_LENGTH) as f64 / SAMPLE_RATE as f64;
+        let segment_size = usize::min(content_frames - seek, N_FRAMES);
+        let mel_segment = mel.narrow(2, seek, segment_size)?;
+        let segment_duration = (segment_size * HOP_LENGTH) as f64 / SAMPLE_RATE as f64;
+        let dr = dc.decode_with_fallback(&mel_segment)?;
+        seek += segment_size;
+        if dr.no_speech_prob > NO_SPEECH_THRESHOLD && dr.avg_logprob < LOGPROB_THRESHOLD {
+            println!("no speech detected, skipping {seek} {dr:?}");
+            continue;
+        }
+        let segment = Segment {
+            start: time_offset,
+            duration: segment_duration,
+            dr,
+        };
+        println!("{seek}: {segment:?}");
+        segments.push(segment)
+    }
+    Ok(())
+}
diff --git a/candle-examples/examples/whisper/mel_filters.safetensors b/candle-examples/examples/whisper/mel_filters.safetensors
new file mode 100644
index 00000000..98f3af44
--- /dev/null
+++ b/candle-examples/examples/whisper/mel_filters.safetensors
diff --git a/candle-examples/examples/whisper/model.rs b/candle-examples/examples/whisper/model.rs
new file mode 100644
index 00000000..53ee6a90
--- /dev/null
+++ b/candle-examples/examples/whisper/model.rs
@@ -0,0 +1,547 @@
+// We use anyhow rather than candle errors as it provides better support for getting the backtrace
+// back when using RUST_LIB_BACKTRACE=1.
+use anyhow::Result;
+use candle::{safetensors::SafeTensors, DType, Device, Shape, Tensor};
+use std::collections::HashMap;
+
+pub struct VarBuilder<'a> {
+    safetensors: Option<(HashMap<String, usize>, Vec<SafeTensors<'a>>)>,
+    dtype: DType,
+    device: Device,
+}
+
+impl<'a> VarBuilder<'a> {
+    pub fn from_safetensors(
+        safetensors: Vec<SafeTensors<'a>>,
+        dtype: DType,
+        device: Device,
+    ) -> Self {
+        let mut routing = HashMap::new();
+        for (index, sf) in safetensors.iter().enumerate() {
+            for k in sf.names() {
+                routing.insert(k.to_string(), index);
+            }
+        }
+        Self {
+            safetensors: Some((routing, safetensors)),
+            device,
+            dtype,
+        }
+    }
+
+    pub fn zeros(dtype: DType, device: Device) -> Self {
+        Self {
+            safetensors: None,
+            device,
+            dtype,
+        }
+    }
+
+    pub fn get<S: Into<Shape>>(&self, s: S, tensor_name: &str) -> candle::Result<Tensor> {
+        let s: Shape = s.into();
+        match &self.safetensors {
+            None => Tensor::zeros(s, self.dtype, &self.device),
+            Some((routing, safetensors)) => {
+                // Unwrap or 0  just to let the proper error flow.
+                let index = routing.get(tensor_name).unwrap_or(&0);
+                let tensor = safetensors[*index]
+                    .tensor(tensor_name, &self.device)?
+                    .to_dtype(self.dtype)?;
+                if *tensor.shape() != s {
+                    let msg = format!("shape mismatch for {tensor_name}");
+                    Err(candle::Error::UnexpectedShape {
+                        msg,
+                        expected: s,
+                        got: tensor.shape().clone(),
+                    })?
+                }
+                Ok(tensor)
+            }
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum HiddenAct {
+    Gelu,
+    Relu,
+}
+
+impl HiddenAct {
+    fn forward(&self, xs: &Tensor) -> candle::Result<Tensor> {
+        match self {
+            Self::Gelu => xs.gelu(),
+            Self::Relu => xs.relu(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Config {
+    pub n_mels: usize,
+    pub n_audio_ctx: usize,
+    pub n_audio_state: usize,
+    pub n_audio_head: usize,
+    pub n_audio_layer: usize,
+    pub n_vocab: usize,
+    pub n_text_ctx: usize,
+    pub n_text_state: usize,
+    pub n_text_head: usize,
+    pub n_text_layer: usize,
+}
+
+impl Config {
+    pub fn tiny_en() -> Self {
+        Self {
+            n_mels: 80,
+            n_vocab: 51864,
+            n_audio_ctx: 1500,
+            n_audio_state: 384,
+            n_audio_head: 6,
+            n_audio_layer: 4,
+            n_text_ctx: 448,
+            n_text_state: 384,
+            n_text_head: 6,
+            n_text_layer: 4,
+        }
+    }
+}
+
+struct Embedding {
+    embeddings: Tensor,
+    hidden_size: usize,
+}
+
+impl Embedding {
+    fn new(embeddings: Tensor, hidden_size: usize) -> Self {
+        Self {
+            embeddings,
+            hidden_size,
+        }
+    }
+
+    fn load(vocab_size: usize, hidden_size: usize, p: &str, vb: &VarBuilder) -> Result<Self> {
+        let embeddings = vb.get((vocab_size, hidden_size), &format!("{p}.weight"))?;
+        Ok(Self::new(embeddings, hidden_size))
+    }
+
+    fn forward(&self, indexes: &Tensor) -> Result<Tensor> {
+        let mut final_dims = indexes.dims().to_vec();
+        final_dims.push(self.hidden_size);
+        let indexes = indexes.flatten_all()?;
+        let values = Tensor::embedding(&indexes, &self.embeddings)?;
+        let values = values.reshape(final_dims)?;
+        Ok(values)
+    }
+}
+
+struct Linear {
+    weight: Tensor,
+    bias: Option<Tensor>,
+}
+
+impl Linear {
+    fn load(size1: usize, size2: usize, p: &str, vb: &VarBuilder) -> Result<Self> {
+        let weight = vb.get((size2, size1), &format!("{p}.weight"))?;
+        let bias = vb.get(size2, &format!("{p}.bias"))?;
+        Ok(Self {
+            weight,
+            bias: Some(bias),
+        })
+    }
+
+    fn load_no_bias(size1: usize, size2: usize, p: &str, vb: &VarBuilder) -> Result<Self> {
+        let weight = vb.get((size2, size1), &format!("{p}.weight"))?;
+        Ok(Self { weight, bias: None })
+    }
+
+    fn forward(&self, x: &Tensor) -> candle::Result<Tensor> {
+        let (bsize, _, _) = x.shape().r3()?;
+        let w = self.weight.broadcast_left(bsize)?.t()?;
+        let x = x.matmul(&w)?;
+        match &self.bias {
+            None => Ok(x),
+            Some(bias) => x.broadcast_add(bias),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct ConvConfig {
+    padding: usize,
+    stride: usize,
+}
+
+impl Default for ConvConfig {
+    fn default() -> Self {
+        Self {
+            padding: 0,
+            stride: 1,
+        }
+    }
+}
+
+struct Conv1D {
+    weight: Tensor,
+    bias: Option<Tensor>,
+    config: ConvConfig,
+}
+
+impl Conv1D {
+    fn load(
+        in_channels: usize,
+        out_channels: usize,
+        kernel_size: usize,
+        config: ConvConfig,
+        p: &str,
+        vb: &VarBuilder,
+    ) -> Result<Self> {
+        let weight = vb.get(
+            (out_channels, in_channels, kernel_size),
+            &format!("{p}.weight"),
+        )?;
+        let bias = vb.get(out_channels, &format!("{p}.bias"))?;
+        Ok(Self {
+            weight,
+            bias: Some(bias),
+            config,
+        })
+    }
+
+    fn load_no_bias(
+        in_channels: usize,
+        out_channels: usize,
+        kernel_size: usize,
+        config: ConvConfig,
+        p: &str,
+        vb: &VarBuilder,
+    ) -> Result<Self> {
+        let weight = vb.get(
+            (out_channels, in_channels, kernel_size),
+            &format!("{p}.weight"),
+        )?;
+        Ok(Self {
+            weight,
+            bias: None,
+            config,
+        })
+    }
+
+    fn forward(&self, x: &Tensor) -> Result<Tensor> {
+        let x = x.conv1d(&self.weight, self.config.padding, self.config.stride)?;
+        match &self.bias {
+            None => Ok(x),
+            Some(bias) => {
+                let b = bias.shape().r1()?;
+                let bias = bias.reshape((1, b, 1))?;
+                Ok(x.broadcast_add(&bias)?)
+            }
+        }
+    }
+}
+
+struct Dropout {
+    pr: f64,
+}
+
+impl Dropout {
+    fn new(pr: f64) -> Self {
+        Self { pr }
+    }
+
+    fn forward(&self, x: &Tensor) -> Result<Tensor> {
+        // TODO
+        Ok(x.clone())
+    }
+}
+
+// This layer norm version handles both weight and bias so removes the mean.
+struct LayerNorm {
+    weight: Tensor,
+    bias: Tensor,
+    eps: f64,
+}
+
+impl LayerNorm {
+    fn load(size: usize, p: &str, vb: &VarBuilder) -> Result<Self> {
+        let weight = vb.get(size, &format!("{p}.weight"))?;
+        let bias = vb.get(size, &format!("{p}.bias"))?;
+        Ok(Self {
+            weight,
+            bias,
+            eps: 1e-5,
+        })
+    }
+
+    fn forward(&self, x: &Tensor) -> Result<Tensor> {
+        let (_bsize, _seq_len, hidden_size) = x.shape().r3()?;
+        let mean_x = (x.sum(&[2])? / hidden_size as f64)?;
+        let x = x.broadcast_sub(&mean_x)?;
+        let norm_x = ((&x * &x)?.sum(&[2])? / hidden_size as f64)?;
+        let x_normed = x.broadcast_div(&(norm_x + self.eps)?.sqrt()?)?;
+        let x = x_normed
+            .broadcast_mul(&self.weight)?
+            .broadcast_add(&self.bias)?;
+        Ok(x)
+    }
+}
+
+// https://github.com/openai/whisper/blob/f572f2161ba831bae131364c3bffdead7af6d210/whisper/model.py#L62
+struct MultiHeadAttention {
+    query: Linear,
+    key: Linear,
+    value: Linear,
+    out: Linear,
+    n_head: usize,
+}
+
+impl MultiHeadAttention {
+    fn load(n_state: usize, n_head: usize, p: &str, vb: &VarBuilder) -> Result<Self> {
+        let query = Linear::load(n_state, n_state, &format!("{p}.query"), vb)?;
+        let value = Linear::load(n_state, n_state, &format!("{p}.value"), vb)?;
+        let key = Linear::load_no_bias(n_state, n_state, &format!("{p}.key"), vb)?;
+        let out = Linear::load(n_state, n_state, &format!("{p}.out"), vb)?;
+        Ok(Self {
+            query,
+            key,
+            value,
+            out,
+            n_head,
+        })
+    }
+
+    fn forward(&self, x: &Tensor, xa: Option<&Tensor>, mask: Option<&Tensor>) -> Result<Tensor> {
+        let q = self.query.forward(x)?;
+        let k = self.key.forward(xa.unwrap_or(x))?;
+        let v = self.value.forward(xa.unwrap_or(x))?;
+        let wv = self.qkv_attention(&q, &k, &v, mask)?;
+        let out = self.out.forward(&wv)?;
+        Ok(out)
+    }
+
+    fn reshape_head(&self, x: &Tensor) -> Result<Tensor> {
+        let (n_batch, n_ctx, n_state) = x.shape().r3()?;
+        let target_dims = &[n_batch, n_ctx, self.n_head, n_state / self.n_head];
+        Ok(x.reshape(target_dims)?.transpose(1, 2)?)
+    }
+
+    fn qkv_attention(
+        &self,
+        q: &Tensor,
+        k: &Tensor,
+        v: &Tensor,
+        mask: Option<&Tensor>,
+    ) -> Result<Tensor> {
+        let (_, n_ctx, n_state) = q.shape().r3()?;
+        let scale = ((n_state / self.n_head) as f64).powf(-0.25);
+        let q = (self.reshape_head(q)? * scale)?;
+        let k = (self.reshape_head(k)?.transpose(2, 3)? * scale)?;
+        let v = self.reshape_head(v)?.contiguous()?;
+        let mut qk = q.matmul(&k)?;
+        if let Some(mask) = mask {
+            let mask = mask.narrow(0, 0, n_ctx)?.narrow(1, 0, n_ctx)?;
+            qk = qk.broadcast_add(&mask)?
+        }
+        let w = qk.softmax(qk.rank() - 1)?;
+        let wv = w.matmul(&v)?.transpose(1, 2)?.flatten(Some(2), None)?;
+        Ok(wv)
+    }
+}
+
+// https://github.com/openai/whisper/blob/f572f2161ba831bae131364c3bffdead7af6d210/whisper/model.py#L111
+struct ResidualAttentionBlock {
+    attn: MultiHeadAttention,
+    attn_ln: LayerNorm,
+    cross_attn: Option<(MultiHeadAttention, LayerNorm)>,
+    mlp_linear1: Linear,
+    mlp_linear2: Linear,
+    mlp_ln: LayerNorm,
+}
+
+impl ResidualAttentionBlock {
+    fn load(n_state: usize, n_head: usize, ca: bool, p: &str, vb: &VarBuilder) -> Result<Self> {
+        let attn = MultiHeadAttention::load(n_state, n_head, &format!("{p}.attn"), vb)?;
+        let attn_ln = LayerNorm::load(n_state, &format!("{p}.attn_ln"), vb)?;
+        let cross_attn = if ca {
+            let cross_attn =
+                MultiHeadAttention::load(n_state, n_head, &format!("{p}.cross_attn"), vb)?;
+            let cross_attn_ln = LayerNorm::load(n_state, &format!("{p}.cross_attn_ln"), vb)?;
+            Some((cross_attn, cross_attn_ln))
+        } else {
+            None
+        };
+        let n_mlp = n_state * 4;
+        let mlp_linear1 = Linear::load(n_state, n_mlp, &format!("{p}.mlp.0"), vb)?;
+        let mlp_linear2 = Linear::load(n_mlp, n_state, &format!("{p}.mlp.2"), vb)?;
+        let mlp_ln = LayerNorm::load(n_state, &format!("{p}.mlp_ln"), vb)?;
+        Ok(Self {
+            attn,
+            attn_ln,
+            cross_attn,
+            mlp_linear1,
+            mlp_linear2,
+            mlp_ln,
+        })
+    }
+
+    fn forward(&self, x: &Tensor, xa: Option<&Tensor>, mask: Option<&Tensor>) -> Result<Tensor> {
+        let attn = self.attn.forward(&self.attn_ln.forward(x)?, None, mask)?;
+        let mut x = (x + attn)?;
+        if let Some((attn, ln)) = &self.cross_attn {
+            x = (&x + attn.forward(&ln.forward(&x)?, xa, None)?)?;
+        }
+        let mlp = self.mlp_linear2.forward(
+            &self
+                .mlp_linear1
+                .forward(&self.mlp_ln.forward(&x)?)?
+                .gelu()?,
+        )?;
+        Ok((x + mlp)?)
+    }
+}
+
+fn sinusoids(length: usize, channels: usize) -> Result<Tensor> {
+    let max_timescale = 10000f32;
+    let log_timescale_increment = max_timescale.ln() / (channels / 2 - 1) as f32;
+    let inv_timescales: Vec<_> = (0..channels / 2)
+        .map(|i| (i as f32 * (-log_timescale_increment)).exp())
+        .collect();
+    let arange: Vec<_> = (0..length).map(|c| c as f32).collect();
+    let inv_timescales = Tensor::new(inv_timescales.as_slice(), &Device::Cpu)?.unsqueeze(0)?;
+    let arange = Tensor::new(arange.as_slice(), &Device::Cpu)?.unsqueeze(1)?;
+    let sh = (length, channels / 2);
+    let scaled_time = (arange.broadcast_as(sh)? * inv_timescales.broadcast_as(sh)?)?;
+    let sincos = Tensor::cat(&[scaled_time.sin()?, scaled_time.cos()?], 1)?;
+    Ok(sincos)
+}
+
+// https://github.com/openai/whisper/blob/f572f2161ba831bae131364c3bffdead7af6d210/whisper/model.py#L143
+pub struct AudioEncoder {
+    conv1: Conv1D,
+    conv2: Conv1D,
+    positional_embedding: Tensor,
+    blocks: Vec<ResidualAttentionBlock>,
+    ln_post: LayerNorm,
+}
+
+impl AudioEncoder {
+    fn load(p: &str, vb: &VarBuilder, cfg: &Config) -> Result<Self> {
+        let n_state = cfg.n_audio_state;
+        let n_head = cfg.n_audio_head;
+        let n_ctx = cfg.n_audio_ctx;
+        let cfg1 = ConvConfig {
+            padding: 1,
+            stride: 1,
+        };
+        let cfg2 = ConvConfig {
+            padding: 1,
+            stride: 2,
+        };
+        let conv1 = Conv1D::load(cfg.n_mels, n_state, 3, cfg1, &format!("{p}.conv1"), vb)?;
+        let conv2 = Conv1D::load(n_state, n_state, 3, cfg2, &format!("{p}.conv2"), vb)?;
+        let positional_embedding = sinusoids(n_ctx, n_state)?.to_device(&vb.device)?;
+        let blocks = (0..cfg.n_audio_layer)
+            .map(|i| {
+                ResidualAttentionBlock::load(n_state, n_head, false, &format!("{p}.blocks.{i}"), vb)
+            })
+            .collect::<Result<Vec<_>>>()?;
+        let ln_post = LayerNorm::load(n_state, &format!("{p}.ln_post"), vb)?;
+        Ok(Self {
+            conv1,
+            conv2,
+            positional_embedding,
+            blocks,
+            ln_post,
+        })
+    }
+    pub fn forward(&self, x: &Tensor) -> Result<Tensor> {
+        let x = self.conv1.forward(x)?.gelu()?;
+        let x = self.conv2.forward(&x)?.gelu()?;
+        let x = x.transpose(1, 2)?;
+        let mut x = x.broadcast_add(&self.positional_embedding)?;
+        for block in self.blocks.iter() {
+            x = block.forward(&x, None, None)?
+        }
+        let x = self.ln_post.forward(&x)?;
+        Ok(x)
+    }
+}
+
+// https://github.com/openai/whisper/blob/f572f2161ba831bae131364c3bffdead7af6d210/whisper/model.py#L176
+pub struct TextDecoder {
+    token_embedding: Embedding,
+    positional_embedding: Tensor,
+    blocks: Vec<ResidualAttentionBlock>,
+    ln: LayerNorm,
+    mask: Tensor,
+}
+
+impl TextDecoder {
+    fn load(p: &str, vb: &VarBuilder, cfg: &Config) -> Result<Self> {
+        let n_state = cfg.n_text_state;
+        let n_head = cfg.n_text_head;
+        let n_ctx = cfg.n_text_ctx;
+        let token_embedding =
+            Embedding::load(cfg.n_vocab, n_state, &format!("{p}.token_embedding"), vb)?;
+        let positional_embedding =
+            vb.get((n_ctx, n_state), &format!("{p}.positional_embedding"))?;
+        let blocks = (0..cfg.n_text_layer)
+            .map(|i| {
+                ResidualAttentionBlock::load(n_state, n_head, true, &format!("{p}.blocks.{i}"), vb)
+            })
+            .collect::<Result<Vec<_>>>()?;
+        let ln = LayerNorm::load(n_state, &format!("{p}.ln"), vb)?;
+        let mask: Vec<_> = (0..n_ctx)
+            .flat_map(|i| (0..n_ctx).map(move |j| if j > i { f32::NEG_INFINITY } else { 0f32 }))
+            .collect();
+        let mask = Tensor::from_vec(mask, (n_ctx, n_ctx), &vb.device)?;
+
+        Ok(Self {
+            token_embedding,
+            positional_embedding,
+            blocks,
+            ln,
+            mask,
+        })
+    }
+
+    pub fn forward(&self, x: &Tensor, xa: &Tensor) -> Result<Tensor> {
+        let x_dims = x.dims();
+        let last = x_dims[x_dims.len() - 1];
+        let token_embedding = self.token_embedding.forward(x)?;
+        let positional_embedding = self.positional_embedding.narrow(0, 0, last)?;
+        let mut x = token_embedding.broadcast_add(&positional_embedding)?;
+        for block in self.blocks.iter() {
+            x = block.forward(&x, Some(xa), Some(&self.mask))?;
+        }
+        let x = self.ln.forward(&x)?;
+        let w = self.token_embedding.embeddings.broadcast_left(x_dims[0])?;
+        let logits = x.matmul(&w.t()?)?;
+        Ok(logits)
+    }
+}
+
+// https://github.com/openai/whisper/blob/f572f2161ba831bae131364c3bffdead7af6d210/whisper/model.py#L221
+pub struct Whisper {
+    pub encoder: AudioEncoder,
+    pub decoder: TextDecoder,
+    pub config: Config,
+}
+
+impl Whisper {
+    pub fn load(vb: &VarBuilder, config: Config) -> Result<Self> {
+        let encoder = AudioEncoder::load("encoder", vb, &config)?;
+        let decoder = TextDecoder::load("decoder", vb, &config)?;
+        Ok(Self {
+            encoder,
+            decoder,
+            config,
+        })
+    }
+
+    pub fn forward(&self, mel: &Tensor, tokens: &Tensor) -> Result<Tensor> {
+        let enc = self.encoder.forward(mel)?;
+        let dec = self.decoder.forward(tokens, &enc)?;
+        Ok(dec)
+    }
+}