fixed hessian calc when hessian is 0 #77

	name: Docs
	on: [push, pull_request]
	jobs:
	build-docs:
	runs-on: ubuntu-latest
	steps:
	- name: Checkout repository and submodules
	uses: actions/checkout@v2
	with:
	submodules: recursive
	- name: Setup Python 3.9
	uses: actions/setup-python@v2
	with:
	python-version: 3.9
	- name: Install pandoc
	run: \|
	sudo apt-get update
	sudo apt-get install pandoc
	- name: Install doc requirements
	run: \|
	python -m pip install --upgrade pip
	pip install -r doc_requirements.txt
	- name : Install MPI
	run: \|
	sudo apt-get install -y mpich libmpich-dev
	- name : Install Bingo requirements (for tutorials)
	run: \|
	pip install -r requirements.txt
	- name: Build docs
	run: \|
	sphinx-apidoc -f -o docs/source/_apidocs bingo
	sphinx-build -b html docs/source/ docs/build/html
	- name: Deploy to gh-pages branch
	uses: peaceiris/actions-gh-pages@v3
	if: github.ref == 'refs/heads/develop_docs'
	with:
	github_token: ${{ secrets.GITHUB_TOKEN }}
	publish_dir: docs/build/html

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