You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: prove.go
    path of file: ./repos/gnark/backend/groth16/bls24-315
    
    the code of the file until where you have to start completion: // Copyright 2020 ConsenSys Software Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a c
    
func computeH(a, b, c []fr.Element, domain *fft.Domain) []fr.Element {
	// H part of Krs
	// Compute H (hz=ab-c, where z=-2 on ker X^n+1 (z(x)=x^n-1))
	// 	1 - _a = ifft(a), _b = ifft(b), _c = ifft(c)
	// 	2 - ca = fft_coset(_a), ba = fft_coset(_b), cc = fft_coset(_c)
	// 	3 - h = ifft_coset(ca o cb - cc)

	n := len(a)

	// add padding to ensure input length is domain cardinality
	padding := make([]fr.Element, int(domain.Cardinality)-n)
	a = append(a, padding...)
	b = append(b, padding...)
	c = append(c, padding...)
	n = len(a)

	domain.FFTInverse(a, fft.DIF)
	domain.FFTInverse(b, fft.DIF)
	domain.FFTInverse(c, fft.DIF)

	domain.FFT(a, fft.DIT, fft.OnCoset())
	domain.FFT(b, fft.DIT, fft.OnCoset())
	domain.FFT(c, fft.DIT, fft.OnCoset())

	var den, one fr.Element
	one.SetOne()
	den.Exp(domain.FrMultiplicativeGen, big.NewInt(int64(domain.Cardinality)))
	den.Sub(&den, &one).Inverse(&den)

	// h = ifft_coset(ca o cb - cc)
	// reusing a to avoid unnecessary memory allocation
	utils.Parallelize(n, func(start, end int) {
		for i := start; i < end; i++ {
			a[i].Mul(&a[i], &b[i]).
				Sub(&a[i], &c[i]).
				Mul(&a[i], &den)
		}
	})

	// ifft_coset
	domain.FFTInverse(a, fft.DIF, fft.OnCoset())

	return a
}