fn render()

in crates/ratchet-core/src/ops/cache.rs [51:105]
45 lines of code
4 McCabe index (conditional complexity)

    fn render<P: WgslPrimitive>(
        &self,
        inplace: bool,
        dst: &Tensor,
        workgroup_size: &WorkgroupSize,
    ) -> Result<KernelSource, OperationError> {
        let device = dst.device().try_gpu()?;
        let mut kernel_builder = WgslKernelBuilder::new(
            workgroup_size.clone(),
            rvec![
                BuiltIn::WorkgroupId,
                BuiltIn::LocalInvocationIndex,
                BuiltIn::NumWorkgroups,
            ],
            device.compute_features().clone(),
        );
        self.register_bindings::<P>(&mut kernel_builder, inplace)?;

        kernel_builder.render_metadata(&self.metadata(dst, &self.kernel_element(dst))?);
        kernel_builder.write_offset_to_index();
        kernel_builder.write_index_to_offset();

        kernel_builder.write_main(wgsl! {
            //Dispatch 1 thread per output element
            //dst_offset is index into the output buffer (1D)
            let x_offset = workgroup_id.x * 64u;
            let dst_offset = (workgroup_id.y * num_workgroups.x * 64u) + x_offset + local_invocation_index;
            if (dst_offset >= metadata.dst_numel) {
                return;
            }
            //Convert 1D offset into 4D index
            var dst_index = offsetToNdIndex(dst_offset, metadata.dst_stride);

            let dim = metadata.dim;
            if (dst_index[dim] < metadata.cum0) {
                //Inside cache, just copy from cache to DST
                let src_offset = ndIndexToOffset(dst_index, metadata.cache_stride);
                D[dst_offset] = C[src_offset];
                return;
            }

            if (dst_index[dim] < metadata.cum1) {
                //Inside src, copy from src to cache and then to DST
                let cache_offset = ndIndexToOffset(dst_index, metadata.cache_stride);
                dst_index[dim] -= metadata.cum0;
                let src_offset = ndIndexToOffset(dst_index, metadata.src_stride);
                let val = S[src_offset];
                C[cache_offset] = val;
                D[dst_offset] = val;
                return;
            }
        });

        Ok(kernel_builder.build()?)
    }