{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import adcc\n",
    "import psi4\n",
    "from matplotlib import pyplot as plt\n",
    "\n",
    "adcc.set_n_threads(4)  # Set to 4 threads"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Run SCF in Psi4\n",
    "mol = psi4.geometry(\"\"\"\n",
    "    units au\n",
    "    symmetry c1\n",
    "    O 0 0 0\n",
    "    H 0 0 1.795239827225189\n",
    "    H 1.693194615993441 0 -0.599043184453037\n",
    "\"\"\")\n",
    "psi4.core.be_quiet()\n",
    "psi4.set_options({'basis': \"cc-pvtz\", 'e_convergence': 1e-7})\n",
    "_, wfn = psi4.energy('SCF', return_wfn=True)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Run ADC(1) on 7 singlets\n",
    "n_singlets = 7\n",
    "adc_1 = adcc.adc1(wfn, n_singlets=n_singlets)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Build guess for ADC(2) by appending a zero doubles part to each vector\n",
    "adc2matrix = adcc.AdcMatrix(\"adc2\", adc_1.ground_state)\n",
    "def append_doubles_block(adc1_vector):\n",
    "    symmetries = adcc.guess_symmetries(adc2matrix,\n",
    "                                       spin_block_symmetrisation=\"symmetric\")\n",
    "    return adcc.AmplitudeVector(adc1_vector[\"s\"], adcc.Tensor(symmetries[1]))\n",
    "guesses_1 = [append_doubles_block(exv) for exv in adc_1.excitation_vectors]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Run ADC(2), ADC(2x) and ADC(3)\n",
    "adc_2 =  adcc.adc2(adc2matrix, n_singlets=n_singlets, guesses=guesses_1)\n",
    "adc_x = adcc.adc2x(adc_2.ground_state, n_singlets=n_singlets,\n",
    "                     guesses=adc_2.excitation_vectors)\n",
    "adc_3 =  adcc.adc3(adc_x.ground_state, n_singlets=n_singlets,\n",
    "                     guesses=adc_x.excitation_vectors)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "adc_1.plot_spectrum(label=\"ADC(1)\")\n",
    "adc_2.plot_spectrum(label=\"ADC(2)\")\n",
    "adc_x.plot_spectrum(label=\"ADC(2)-x\")\n",
    "adc_3.plot_spectrum(label=\"ADC(3)\")\n",
    "plt.legend()"
   ]
  }
 ],
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