*Result*: Correctness Meets Performance:From Agda to Futhark
*Further Information*
*In this paper we demonstrate a technique for developing high performance applications with strong correctness guarantees. Using a theorem prover, we derive a high-level specification of the application that includes correctness invariants of our choice. After that, within the same theorem prover, we implement an extraction of the specified application into a high-performance language of our choice. Concretely, we are using Agda to specify a framework for automatic differentiation (reverse mode) that is focused on index-safe tensors. This framework comes with an optimiser for tensor expressions and the ability to translate these expressions into Futhark. We specify a canonical convolutional neural network within the proposed framework, compute the derivatives needed for the training phase and then demonstrate that the generated code approaches the performance of TensorFlow code when running on a GPU.*