Add the conv-transpose1d op. (#1251)

* Skeleton structure for conv-transpose1d.

* CPU implementation for conv-transpose1d.

candle-core/src/backend.rs

@@ -39,6 +39,14 @@ pub trait BackendStorage: Sized {
         _params: &crate::conv::ParamsConv1D,
     ) -> Result<Self>;
 
+    fn conv_transpose1d(
+        &self,
+        _l: &Layout,
+        _kernel: &Self,
+        _kernel_l: &Layout,
+        _params: &crate::conv::ParamsConvTranspose1D,
+    ) -> Result<Self>;
+
     fn conv2d(
         &self,
         _l: &Layout,

candle-core/src/backprop.rs

@@ -57,6 +57,11 @@ impl Tensor {
                         kernel: rhs,
                         ..
                     }
+                    | Op::ConvTranspose1D {
+                        arg: lhs,
+                        kernel: rhs,
+                        ..
+                    }
                     | Op::Conv2D {
                         arg: lhs,
                         kernel: rhs,
@@ -247,6 +252,9 @@ impl Tensor {
                         };
                         *sum_grad = sum_grad.add(&grad_kernel)?;
                     }
+                    Op::ConvTranspose1D { .. } => Err(Error::BackwardNotSupported {
+                        op: "conv-transpose1d",
+                    })?,
                     Op::ConvTranspose2D { .. } => Err(Error::BackwardNotSupported {
                         op: "conv-transpose2d",
                     })?,

candle-core/src/conv.rs

@@ -25,6 +25,33 @@ impl ParamsConv1D {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ParamsConvTranspose1D {
+    pub(crate) b_size: usize,
+    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) output_padding: usize,
+    pub(crate) stride: usize,
+    pub(crate) dilation: usize,
+}
+
+impl ParamsConvTranspose1D {
+    pub(crate) fn l_out(&self) -> usize {
+        (self.l_in - 1) * self.stride - 2 * self.padding
+            + self.dilation * (self.k_size - 1)
+            + self.output_padding
+            + 1
+    }
+
+    pub(crate) fn out_dims(&self) -> Vec<usize> {
+        let l_out = self.l_out();
+        vec![self.b_size, self.c_out, l_out]
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum CudnnFwdAlgo {
     ImplicitGemm,
@@ -160,6 +187,49 @@ impl Tensor {
         }
     }
 
+    /// Applies a 1D transposed convolution over the input tensor.
+    pub fn conv_transpose1d(
+        &self,
+        kernel: &Self,
+        padding: usize,
+        output_padding: usize,
+        stride: usize,
+        dilation: usize,
+    ) -> Result<Self> {
+        let (c_out, c_in_k, k_size) = kernel.dims3()?;
+        let (b_size, c_in, l_in) = self.dims3()?;
+        if c_in != c_in_k {
+            crate::bail!("in_channel mismatch between input ({c_in}) and kernel ({c_in_k})")
+        }
+        let params = ParamsConvTranspose1D {
+            b_size,
+            l_in,
+            k_size,
+            c_out,
+            c_in,
+            padding,
+            output_padding,
+            stride,
+            dilation,
+        };
+        let storage = self.storage().conv_transpose1d(
+            self.layout(),
+            &kernel.storage(),
+            kernel.layout(),
+            &params,
+        )?;
+        let op = BackpropOp::new2(self, kernel, |arg, kernel| Op::ConvTranspose1D {
+            arg,
+            kernel,
+            padding: params.padding,
+            output_padding: params.output_padding,
+            stride: params.stride,
+            dilation: params.dilation,
+        });
+        let out_dims = params.out_dims();
+        Ok(crate::tensor::from_storage(storage, out_dims, op, false))
+    }
+
     fn conv2d_single_group(&self, kernel: &Self, params: &ParamsConv2D) -> Result<Self> {
         let storage =
             self.storage()

candle-core/src/cpu_backend.rs

@@ -1256,6 +1256,74 @@ impl Map1 for Im2Col {
     }
 }
 
+struct ConvTranspose1D<'a>(&'a crate::conv::ParamsConvTranspose1D);
+
+impl<'a> Map2 for ConvTranspose1D<'a> {
+    const OP: &'static str = "conv_transpose1d";
+    fn f<T: WithDType>(&self, inp: &[T], inp_l: &Layout, k: &[T], k_l: &Layout) -> Result<Vec<T>> {
+        let p = self.0;
+        let inp = &inp[inp_l.start_offset()..];
+        let (inp_s0, inp_s1, inp_s2) = crate::shape::dims3(inp_l.stride())?;
+        let (k_s0, k_s1, k_s2) = crate::shape::dims3(k_l.stride())?;
+        let l_out = p.l_out();
+
+        // Output shape: [b_size, c_out, l_out].
+        let dst_elems = p.c_out * l_out * p.b_size;
+        let dst = vec![T::zero(); dst_elems];
+        let dst_s0 = p.c_out * l_out;
+        let dst_s1 = l_out;
+        let dst_s2 = 1;
+
+        // TODO: Avoid making this copy if `inp` already has the appropriate layout.
+        let mut inp_cont = vec![T::zero(); p.b_size * p.c_in * p.l_in];
+        let cont_s0 = p.l_in * p.c_in;
+        let cont_s1 = p.c_in;
+        for b_idx in 0..p.b_size {
+            for l_idx in 0..p.l_in {
+                for c_idx in 0..p.c_in {
+                    let src_idx = b_idx * inp_s0 + c_idx * inp_s1 + l_idx * inp_s2;
+                    let dst_idx = b_idx * cont_s0 + l_idx * cont_s1 + c_idx;
+                    inp_cont[dst_idx] = inp[src_idx]
+                }
+            }
+        }
+
+        for k_idx in 0..p.k_size {
+            (0..p.c_out).into_par_iter().for_each(|dst_c_idx| {
+                let k_cont = (0..p.c_in)
+                    .map(|c_in_idx| k[c_in_idx * k_s0 + dst_c_idx * k_s1 + k_idx * k_s2])
+                    .collect::<Vec<_>>();
+                for b_idx in 0..p.b_size {
+                    for l_idx in 0..p.l_in {
+                        let out_idx = l_idx * p.stride + k_idx * p.dilation;
+                        if out_idx < p.padding {
+                            continue;
+                        }
+                        let out_idx = out_idx - p.padding;
+                        if out_idx < l_out {
+                            let inp_cont = &inp_cont[b_idx * cont_s0 + l_idx * cont_s1..];
+                            let dst_idx = b_idx * dst_s0 + out_idx * dst_s2 + dst_c_idx * dst_s1;
+                            let mut d = T::zero();
+                            unsafe {
+                                T::vec_dot(inp_cont.as_ptr(), k_cont.as_ptr(), &mut d, p.c_in)
+                            }
+                            let dst_p = dst.as_ptr();
+                            // Safety: dst_idx are uniques per dst_c_idx which is used to
+                            // parallelise the different tasks so no two threads can try to
+                            // write at the same location.
+                            unsafe {
+                                let ptr = dst_p.add(dst_idx) as *mut T;
+                                *ptr += d
+                            }
+                        }
+                    }
+                }
+            })
+        }
+        Ok(dst)
+    }
+}
+
 struct Conv2D<'a>(&'a crate::conv::ParamsConv2D);
 
 impl<'a> Map2 for Conv2D<'a> {
@@ -2435,6 +2503,16 @@ impl BackendStorage for CpuStorage {
         Ok(res_t)
     }
 
+    fn conv_transpose1d(
+        &self,
+        l: &Layout,
+        kernel: &Self,
+        kernel_l: &Layout,
+        params: &crate::conv::ParamsConvTranspose1D,
+    ) -> Result<Self> {
+        ConvTranspose1D(params).map(self, l, kernel, kernel_l)
+    }
+
     fn conv2d(
         &self,
         l: &Layout,

candle-core/src/cuda_backend.rs

@@ -1808,6 +1808,16 @@ impl BackendStorage for CudaStorage {
         Ok(res_t)
     }
 
+    fn conv_transpose1d(
+        &self,
+        _: &Layout,
+        _: &Self,
+        _: &Layout,
+        _: &crate::conv::ParamsConvTranspose1D,
+    ) -> Result<Self> {
+        todo!()
+    }
+
     #[cfg(not(feature = "cudnn"))]
     fn conv2d(
         &self,

candle-core/src/dummy_cuda_backend.rs

@@ -79,6 +79,16 @@ impl crate::backend::BackendStorage for CudaStorage {
         Err(Error::NotCompiledWithCudaSupport)
     }
 
+    fn conv_transpose1d(
+        &self,
+        _: &Layout,
+        _: &Self,
+        _: &Layout,
+        _: &crate::conv::ParamsConvTranspose1D,
+    ) -> Result<Self> {
+        Err(Error::NotCompiledWithCudaSupport)
+    }
+
     fn conv2d(
         &self,
         _: &Layout,

candle-core/src/op.rs

@@ -90,6 +90,16 @@ pub enum Op {
         dilation: usize,
     },
 
+    #[allow(dead_code)]
+    ConvTranspose1D {
+        arg: Tensor,
+        kernel: Tensor,
+        padding: usize,
+        output_padding: usize,
+        stride: usize,
+        dilation: usize,
+    },
+
     #[allow(dead_code)]
     Conv2D {
         arg: Tensor,

candle-core/src/storage.rs

@@ -279,6 +279,33 @@ impl Storage {
         }
     }
 
+    pub(crate) fn conv_transpose1d(
+        &self,
+        l: &Layout,
+        kernel: &Self,
+        kernel_l: &Layout,
+        params: &crate::conv::ParamsConvTranspose1D,
+    ) -> Result<Self> {
+        self.same_device(kernel, "conv-transpose1d")?;
+        self.same_dtype(kernel, "conv-transpose1d")?;
+        match (self, &kernel) {
+            (Storage::Cpu(inp), Storage::Cpu(kernel)) => {
+                let s = inp.conv_transpose1d(l, kernel, kernel_l, params)?;
+                Ok(Self::Cpu(s))
+            }
+            (Storage::Cuda(inp), Storage::Cuda(kernel)) => {
+                let s = inp.conv_transpose1d(l, kernel, kernel_l, params)?;
+                Ok(Self::Cuda(s))
+            }
+            (lhs, rhs) => Err(Error::DeviceMismatchBinaryOp {
+                lhs: lhs.device().location(),
+                rhs: rhs.device().location(),
+                op: "conv-transpose1d",
+            }
+            .bt()),
+        }
+    }
+
     pub(crate) fn conv2d(
         &self,
         l: &Layout,