Add a metal kernel for col2im1d. (#2214)

* Add a metal kernel for col2im1d.

* Enable the col2im variant.

* Bugfix.

* Revert the quantized tweak.

candle-metal-kernels/src/lib.rs

@@ -1651,6 +1651,39 @@ pub fn call_im2col1d_strided(
     Ok(())
 }
 
+#[allow(clippy::too_many_arguments)]
+pub fn call_col2im1d(
+    device: &Device,
+    command_buffer: &CommandBufferRef,
+    kernels: &Kernels,
+    name: &'static str,
+    shape: &[usize],
+    k_size: usize,
+    stride: usize,
+    input: BufferOffset,
+    output: &Buffer,
+) -> Result<(), MetalKernelError> {
+    let pipeline = kernels.load_pipeline(device, Source::Conv, name)?;
+    let l_in = shape[1];
+    let c_out = shape[2];
+    let l_out = (l_in - 1) * stride + k_size;
+    let dst_el = shape[0] * c_out * l_out;
+
+    let encoder = command_buffer.new_compute_command_encoder();
+    let (thread_group_count, thread_group_size) = linear_split(&pipeline, dst_el);
+    encoder.set_compute_pipeline_state(&pipeline);
+    set_params!(
+        encoder,
+        (dst_el, l_out, l_in, c_out, k_size, stride, &input, output)
+    );
+    encoder.use_resource(input.buffer, metal::MTLResourceUsage::Read);
+    encoder.use_resource(output, metal::MTLResourceUsage::Write);
+    encoder.dispatch_thread_groups(thread_group_count, thread_group_size);
+    encoder.end_encoding();
+
+    Ok(())
+}
+
 #[allow(clippy::too_many_arguments)]
 pub fn call_im2col_strided(
     device: &Device,