#!/usr/bin/env python

"""
@package npt

Runs a simulation to compute condensed phase properties (for example, the density 
or the enthalpy of vaporization) and compute the derivative with respect 
to changing the force field parameters.  This script is a part of ForceBalance.

All code in this repository is released under the BSD 3-Clause License (aka BSD 2.0).
Please see github.com/leeping/forcebalance for more details.
"""
from __future__ import division

#==================#
#| Global Imports |#
#==================#

from builtins import zip
from builtins import range
import os
import sys
import glob
import shutil
import argparse
import traceback
import numpy as np
from copy import deepcopy
from collections import namedtuple, OrderedDict
from forcebalance.forcefield import FF
from forcebalance.nifty import col, flat, lp_dump, lp_load, printcool, printcool_dictionary, statisticalInefficiency, which, _exec, isint, wopen, click
from forcebalance.finite_difference import fdwrap, f1d2p, f12d3p, f1d7p, in_fd
from forcebalance.molecule import Molecule
from forcebalance.output import getLogger
logger = getLogger(__name__)

#========================================================#
#| Global, user-tunable variables (simulation settings) |#
#========================================================#

parser = argparse.ArgumentParser()
parser.add_argument('engine', help='MD program that we are using; choose "openmm", "tinker", "amber" or "gromacs"')
parser.add_argument('temperature',type=float, help='Temperature (K)')
parser.add_argument('pressure',type=float, help='Pressure (Atm)')

args = parser.parse_args()

faststep         = 0.25                    # "fast" timestep (for MTS integrator, if used)
temperature      = args.temperature        # temperature in kelvin
pressure         = args.pressure           # pressure in atmospheres
engname          = args.engine.lower()     # Name of the engine

if engname == "openmm":
    try:
        try:
            from openmm.unit import *
            from openmm import *
            from openmm.app import *
        except ImportError:
            from simtk.unit import *
            from simtk.openmm import *
            from simtk.openmm.app import *

    except:
        traceback.print_exc()
        raise Exception("Cannot import OpenMM modules")
    from forcebalance.openmmio import *
    Engine = OpenMM
elif engname == "gromacs" or engname == "gmx":
    from forcebalance.gmxio import *
    Engine = GMX
elif engname == "tinker":
    from forcebalance.tinkerio import *
    Engine = TINKER
elif engname == "amber":
    from forcebalance.amberio import *
    Engine = AMBER
elif engname == "smirnoff":
    from forcebalance.smirnoffio import *
    Engine = SMIRNOFF
else:
    raise Exception('OpenMM, SMIRNOFF/OpenMM, GROMACS, TINKER, and AMBER are supported at this time.')

#==================#
#|   Subroutines  |#
#==================#

def mean_stderr(ts):
    """ Get mean and standard deviation of a time series. """
    return np.mean(ts), np.std(ts)*np.sqrt(statisticalInefficiency(ts, warn=False)/len(ts))

def bzavg(obs,boltz):
    """ Get the Boltzmann average of an observable. """
    if obs.ndim == 2:
        if obs.shape[0] == len(boltz) and obs.shape[1] == len(boltz):
            raise Exception('Error - both dimensions have length equal to number of snapshots, now confused!')
        elif obs.shape[0] == len(boltz):
            return np.sum(obs*boltz.reshape(-1,1),axis=0)/np.sum(boltz)
        elif obs.shape[1] == len(boltz):
            return np.sum(obs*boltz,axis=1)/np.sum(boltz)
        else:
            raise Exception('The dimensions are wrong!')
    elif obs.ndim == 1:
        return np.dot(obs,boltz)/sum(boltz)
    else:
        raise Exception('The number of dimensions can only be 1 or 2!')

def PrintEDA(EDA, N):
    # Get energy decomposition statistics.
    PrintDict = OrderedDict()
    for key, val in EDA.items():
        val_avg, val_err = mean_stderr(val)
        if val_avg == 0.0: continue
        if val_err == 0.0: continue
        PrintDict[key] = "% 12.4f +- %10.4f [ % 9.4f +- %7.4f ]" % (val_avg, val_err, val_avg/N, val_err/N)
    printcool_dictionary(PrintDict, "Energy Component Analysis, Mean +- Stderr [Per Molecule] (kJ/mol)")

#=============================================#
#|   Functions for differentiating energy    |#
#|            and properties                 |#
#=============================================#

def energy_derivatives(engine, FF, mvals, h, pgrad, length, AGrad=True, dipole=False):

    """
    Compute the first and second derivatives of a set of snapshot
    energies with respect to the force field parameters.

    This basically calls the finite difference subroutine on the
    energy_driver subroutine also in this script.

    @param[in] mvals Mathematical parameter values
    @param[in] h Finite difference step size
    @param[in] phase The phase (liquid, gas) to perform the calculation on
    @param[in] AGrad Switch to turn derivatives on or off; if off, return all zeros
    @param[in] dipole Switch for dipole derivatives.
    @return G First derivative of the energies in a N_param x N_coord array
    @return GDx First derivative of the box dipole moment x-component in a N_param x N_coord array
    @return GDy First derivative of the box dipole moment y-component in a N_param x N_coord array
    @return GDz First derivative of the box dipole moment z-component in a N_param x N_coord array

    """
    G        = np.zeros((FF.np,length))
    GDx      = np.zeros((FF.np,length))
    GDy      = np.zeros((FF.np,length))
    GDz      = np.zeros((FF.np,length))
    if not AGrad:
        return G, GDx, GDy, GDz
    def energy_driver(mvals_):
        FF.make(mvals_)
        if dipole:
            return engine.energy_dipole()
        else:
            return engine.energy()

    ED0      = energy_driver(mvals)
    for i in pgrad:
        logger.info("%i %s\r" % (i, (FF.plist[i] + " "*30)))
        EDG, _   = f12d3p(fdwrap(energy_driver,mvals,i),h,f0=ED0)
        if dipole:
            G[i,:]   = EDG[:,0]
            GDx[i,:] = EDG[:,1]
            GDy[i,:] = EDG[:,2]
            GDz[i,:] = EDG[:,3]
        else:
            G[i,:]   = EDG[:]
    return G, GDx, GDy, GDz

def property_derivatives(engine, FF, mvals, h, pgrad, kT, property_driver, property_kwargs, AGrad=True):

    """ 
    Function for double-checking property derivatives.  This function is called to perform
    a more explicit numerical derivative of the property, rather than going through the 
    fluctuation formula.  It takes longer and is potentially less precise, which means
    it's here mainly as a sanity check.

    @param[in] mvals Mathematical parameter values
    @param[in] h Finite difference step size
    @param[in] phase The phase (liquid, gas) to perform the calculation on
    @param[in] property_driver The function that calculates the property
    @param[in] property_driver A dictionary of arguments that goes into calculating the property
    @param[in] AGrad Switch to turn derivatives on or off; if off, return all zeros
    @return G First derivative of the property

    """
    G        = np.zeros(FF.np)
    if not AGrad:
        return G
    def energy_driver(mvals_):
        FF.make(mvals_)
        return engine.energy_dipole()

    ED0      = energy_driver(mvals)
    E0       = ED0[:,0]
    D0       = ED0[:,1:]
    P0       = property_driver(None, **property_kwargs)
    if 'h_' in property_kwargs:
        H0 = property_kwargs['h_'].copy()
    for i in pgrad:
        logger.info("%s\n" % (FF.plist[i] + " "*30))
        ED1      = fdwrap(energy_driver,mvals,i)(h)
        E1       = ED1[:,0]
        D1       = ED1[:,1:]
        b = np.exp(-(E1-E0)/kT)
        b /= np.sum(b)
        if 'h_' in property_kwargs:
            property_kwargs['h_'] = H0.copy() + (E1-E0)
        if 'd_' in property_kwargs:
            property_kwargs['d_'] = D1.copy()
        S = -1*np.dot(b,np.log(b))
        InfoContent = np.exp(S)
        if InfoContent / len(E0) < 0.1:
            logger.warn("Warning: Effective number of snapshots: % .1f (out of %i)\n" % (InfoContent, len(E0)))
        P1 = property_driver(b=b,**property_kwargs)
        EDM1      = fdwrap(energy_driver,mvals,i)(-h)
        EM1       = EDM1[:,0]
        DM1       = EDM1[:,1:]
        b = np.exp(-(EM1-E0)/kT)
        b /= np.sum(b)
        if 'h_' in property_kwargs:
            property_kwargs['h_'] = H0.copy() + (EM1-E0)
        if 'd_' in property_kwargs:
            property_kwargs['d_'] = DM1.copy()
        S = -1*np.dot(b,np.log(b))
        InfoContent = np.exp(S)
        if InfoContent / len(E0) < 0.1:
            logger.warn("Warning: Effective number of snapshots: % .1f (out of %i)\n" % (InfoContent, len(E0)))
        PM1 = property_driver(b=b,**property_kwargs)
        G[i] = (P1-PM1)/(2*h)
    if 'h_' in property_kwargs:
        property_kwargs['h_'] = H0.copy()
    if 'd_' in property_kwargs:
        property_kwargs['d_'] = D0.copy()
    return G
    
def main():

    """
    Usage: (runcuda.sh) npt.py <openmm|gromacs|tinker|amber> <liquid_nsteps> <liquid_timestep (fs)> <liquid_intvl (ps> <temperature> <pressure>

    This program is meant to be called automatically by ForceBalance on
    a GPU cluster (specifically, subroutines in openmmio.py).  It is
    not easy to use manually.  This is because the force field is read
    in from a ForceBalance 'FF' class.

    I wrote this program because automatic fitting of the density (or
    other equilibrium properties) is computationally intensive, and the
    calculations need to be distributed to the queue.  The main instance
    of ForceBalance (running on my workstation) queues up a bunch of these
    jobs (using Work Queue).  Then, I submit a bunch of workers to GPU
    clusters (e.g. Certainty, Keeneland).  The worker scripts connect to.
    the main instance and receives one of these jobs.

    This script can also be executed locally, if you want to (e.g. for
    debugging).  Just make sure you have the pickled 'forcebalance.p'
    file.

    """

    printcool("ForceBalance condensed phase simulation using engine: %s" % engname.upper(), color=4, bold=True)

    #----
    # Load the ForceBalance pickle file which contains:
    #----
    # - Force field object
    # - Optimization parameters
    # - Options from the Target object that launched this simulation
    # - Switch for whether to evaluate analytic derivatives.
    FF,mvals,TgtOptions,AGrad = lp_load('forcebalance.p')
    FF.ffdir = '.'
    # Write the force field file.
    FF.make(mvals)

    #----
    # Load the options that are set in the ForceBalance input file.
    #----
    # Finite difference step size
    h = TgtOptions['h']
    pgrad = TgtOptions['pgrad']
    # MD options; time step (fs), production steps, equilibration steps, interval for saving data (ps)
    liquid_timestep = TgtOptions['liquid_timestep']
    liquid_nsteps = TgtOptions['liquid_md_steps']
    liquid_nequil = TgtOptions['liquid_eq_steps']
    liquid_intvl = TgtOptions['liquid_interval']
    liquid_fnm = TgtOptions['liquid_coords']
    liquid_nbeads = TgtOptions ['liquid_nbeads']
    gas_timestep = TgtOptions['gas_timestep']
    gas_nsteps = TgtOptions['gas_md_steps']
    gas_nequil = TgtOptions['gas_eq_steps']
    gas_intvl = TgtOptions['gas_interval']
    gas_fnm = TgtOptions['gas_coords']
    gas_nbeads = TgtOptions ['gas_nbeads']

    # Number of threads, multiple timestep integrator, anisotropic box etc.
    threads = TgtOptions.get('md_threads', 1)
    mts = TgtOptions.get('mts_integrator', 0)
    rpmd_beads = TgtOptions.get('rpmd_beads', 0)
    force_cuda = TgtOptions.get('force_cuda', 0)
    nbarostat = TgtOptions.get('n_mcbarostat', 25)
    anisotropic = TgtOptions.get('anisotropic_box', 0)
    minimize = TgtOptions.get('minimize_energy', 1)
    pimd = TgtOptions.get ('pimd',0)

    # Print all options.
    printcool_dictionary(TgtOptions, title="Options from ForceBalance")
    liquid_snapshots = int((liquid_nsteps * liquid_timestep / 1000) / liquid_intvl)
    liquid_iframes = int(1000 * liquid_intvl / liquid_timestep)
    gas_snapshots = int((gas_nsteps * gas_timestep / 1000) / gas_intvl)
    gas_iframes = int(1000 * gas_intvl / gas_timestep)
    logger.info("For the condensed phase system, I will collect %i snapshots spaced apart by %i x %.3f fs time steps\n" \
        % (liquid_snapshots, liquid_iframes, liquid_timestep))
    if liquid_snapshots < 2:
        raise Exception('Please set the number of liquid time steps so that you collect at least two snapshots (minimum %i)' \
                            % (2000 * int(liquid_intvl/liquid_timestep)))
    logger.info("For the gas phase system, I will collect %i snapshots spaced apart by %i x %.3f fs time steps\n" \
        % (gas_snapshots, gas_iframes, gas_timestep))
    if gas_snapshots < 2:
        raise Exception('Please set the number of gas time steps so that you collect at least two snapshots (minimum %i)' \
                            % (2000 * int(gas_intvl/gas_timestep)))

    #----
    # Loading coordinates
    #----
    ML = Molecule(liquid_fnm, toppbc=True)
    MG = Molecule(gas_fnm)
    # Determine the number of molecules in the condensed phase coordinate file.
    NMol = TgtOptions['n_molecules']
    logger.info("There are %i molecules in the liquid\n" % (NMol))

    #----
    # Setting up MD simulations
    #----
    EngOpts = OrderedDict()
    EngOpts["liquid"] = OrderedDict([("coords", liquid_fnm), ("mol", ML), ("pbc", True)])
    if "nonbonded_cutoff" in TgtOptions:
        EngOpts["liquid"]["nonbonded_cutoff"] = TgtOptions["nonbonded_cutoff"]
    if "vdw_cutoff" in TgtOptions:
        EngOpts["liquid"]["vdw_cutoff"] = TgtOptions["vdw_cutoff"]
    EngOpts["gas"] = OrderedDict([("coords", gas_fnm), ("mol", MG), ("pbc", False)])
    GenOpts = OrderedDict([('FF', FF)])
    if engname in ["openmm", "smirnoff"]:
        # OpenMM-specific options
        EngOpts["liquid"]["platname"] = TgtOptions.get("platname", 'CUDA')
        # For now, always run gas phase calculations on the reference platform
        EngOpts["gas"]["platname"] = 'Reference'
        if force_cuda:
            try: Platform.getPlatformByName('CUDA')
            except: raise RuntimeError('Forcing failure because CUDA platform unavailable')
            EngOpts["liquid"]["platname"] = 'CUDA'
        if threads > 1: logger.warn("Setting the number of threads will have no effect on OpenMM engine.\n")
        if engname == "smirnoff":
            if not TgtOptions['liquid_coords'].endswith('.pdb'):
                logger.error("With SMIRNOFF engine, please pass a .pdb file to liquid_coords.")
                raise RuntimeError
            EngOpts["liquid"]["pdb"] = TgtOptions['liquid_coords']
            EngOpts["liquid"]["mol2"] = TgtOptions["mol2"]
            if not TgtOptions['gas_coords'].endswith('.pdb'):
                logger.error("With SMIRNOFF engine, please pass a .pdb file to gas_coords.")
                raise RuntimeError
            EngOpts["gas"]["pdb"] = TgtOptions['gas_coords']
            EngOpts["gas"]["mol2"] = TgtOptions["mol2"]
    elif engname == "gromacs":
        # Gromacs-specific options
        GenOpts["gmxpath"] = TgtOptions["gmxpath"]
        GenOpts["gmxsuffix"] = TgtOptions["gmxsuffix"]
        EngOpts["liquid"]["gmx_top"] = os.path.splitext(liquid_fnm)[0] + ".top"
        EngOpts["liquid"]["gmx_mdp"] = os.path.splitext(liquid_fnm)[0] + ".mdp"
        EngOpts["liquid"]["gmx_eq_barostat"] = TgtOptions["gmx_eq_barostat"]
        EngOpts["gas"]["gmx_top"] = os.path.splitext(gas_fnm)[0] + ".top"
        EngOpts["gas"]["gmx_mdp"] = os.path.splitext(gas_fnm)[0] + ".mdp"
        if force_cuda: logger.warn("force_cuda option has no effect on Gromacs engine.")
        if rpmd_beads > 0: raise RuntimeError("Gromacs cannot handle RPMD.")
        if mts: logger.warn("Gromacs not configured for multiple timestep integrator.")
        if anisotropic: logger.warn("Gromacs not configured for anisotropic box scaling.")
    elif engname == "tinker":
        # Tinker-specific options
        GenOpts["tinkerpath"] = TgtOptions["tinkerpath"]
        EngOpts["liquid"]["tinker_key"] = os.path.splitext(liquid_fnm)[0] + ".key"
        EngOpts["gas"]["tinker_key"] = os.path.splitext(gas_fnm)[0] + ".key"
        if force_cuda: logger.warn("force_cuda option has no effect on Tinker engine.")
        if rpmd_beads > 0: raise RuntimeError("TINKER cannot handle RPMD.")
        if mts: logger.warn("Tinker not configured for multiple timestep integrator.")
    elif engname == "amber":
        # AMBER-specific options
        GenOpts["amberhome"] = TgtOptions["amberhome"]
        if os.path.exists(os.path.splitext(liquid_fnm)[0] + ".mdin"):
            EngOpts["liquid"]["mdin"] = os.path.splitext(liquid_fnm)[0] + ".mdin"
        if os.path.exists(os.path.splitext(gas_fnm)[0] + ".mdin"):
            EngOpts["gas"]["mdin"] = os.path.splitext(gas_fnm)[0] + ".mdin"
        EngOpts["liquid"]["leapcmd"] = os.path.splitext(liquid_fnm)[0] + ".leap"
        EngOpts["gas"]["leapcmd"] = os.path.splitext(gas_fnm)[0] + ".leap"
        EngOpts["liquid"]["pdb"] = liquid_fnm
        EngOpts["gas"]["pdb"] = gas_fnm
        if force_cuda: logger.warn("force_cuda option has no effect on Amber engine.")
        if rpmd_beads > 0: raise RuntimeError("AMBER cannot handle RPMD.")
        if mts: logger.warn("Amber not configured for multiple timestep integrator.")
    EngOpts["liquid"].update(GenOpts)
    EngOpts["gas"].update(GenOpts)
    for i in EngOpts:
        printcool_dictionary(EngOpts[i], "Engine options for %s" % i)

    # Set up MD options
    MDOpts = OrderedDict()
    MDOpts["liquid"] = OrderedDict([("nsteps", liquid_nsteps), ("timestep", liquid_timestep),
                                    ("temperature", temperature), ("pressure", pressure),
                                    ("nequil", liquid_nequil), ("minimize", minimize),
                                    ("nsave", int(1000 * liquid_intvl / liquid_timestep)),
                                    ("verbose", True), ('save_traj', TgtOptions['save_traj']), 
                                    ("threads", threads), ("anisotropic", anisotropic), ("nbarostat", nbarostat),
                                    ("mts", mts), ("rpmd_beads", rpmd_beads), ("faststep", faststep),
                                    ("pimd", pimd), ("nbeads", liquid_nbeads) ])
    MDOpts["gas"] = OrderedDict([("nsteps", gas_nsteps), ("timestep", gas_timestep),
                                 ("temperature", temperature), ("nsave", int(1000 * gas_intvl / gas_timestep)),
                                 ("nequil", gas_nequil), ("minimize", minimize), ("threads", 1), ("mts", mts),
                                 ("rpmd_beads", rpmd_beads), ("faststep", faststep), ("pimd", pimd),
                                 ("nbeads", gas_nbeads)])

    # Energy components analysis disabled for OpenMM MTS because it uses force groups
    if (engname == "openmm" and mts): logger.warn("OpenMM with MTS integrator; energy components analysis will be disabled.\n")

    # Create instances of the MD Engine objects.
    Liquid = Engine(name="liquid", **EngOpts["liquid"])
    Gas = Engine(name="gas", **EngOpts["gas"])

    #=================================================================#
    # Run the simulation for the full system and analyze the results. #
    #=================================================================#

    printcool("Condensed phase molecular dynamics", color=4, bold=True)

    # This line runs the condensed phase simulation.
    click()
    prop_return = Liquid.molecular_dynamics(**MDOpts["liquid"])
    if hasattr(Liquid, 'freeze_atoms'):
        logger.info("Warning: freeze_atoms may result in incorrect system mass and incorrect density calculation\n")
    logger.info("Liquid phase MD simulation took %.3f seconds\n" % click())
    Rhos = prop_return['Rhos']
    Potentials = prop_return['Potentials']
    Kinetics = prop_return['Kinetics']
    Volumes = prop_return['Volumes']
    Dips = prop_return['Dips']
    EDA = prop_return['Ecomps']

    # Create a bunch of physical constants.
    # Energies are in kJ/mol
    # Lengths are in nanometers.
    L = len(Rhos)
    kB = 0.008314472471220214
    T = temperature
    kT = kB * T
    mBeta = -1.0 / kT
    Beta = 1.0 / kT
    atm_unit = 0.061019351687175
    bar_unit = 0.060221417930000
    # This is how I calculated the prefactor for the dielectric constant.
    # eps0 = 8.854187817620e-12 * coulomb**2 / newton / meter**2
    # epsunit = 1.0*(debye**2) / nanometer**3 / BOLTZMANN_CONSTANT_kB / kelvin
    # prefactor = epsunit/eps0/3
    prefactor = 30.348705333964077

    # Gather some physical variables.
    Energies = Potentials + Kinetics
    Ene_avg, Ene_err = mean_stderr(Energies)
    pV = atm_unit * pressure * Volumes
    pV_avg, pV_err = mean_stderr(pV)
    Rho_avg, Rho_err = mean_stderr(Rhos)
    PrintEDA(EDA, NMol)

    #==============================================#
    # Now run the simulation for just the monomer. #
    #==============================================#

    # Run the OpenMM simulation, gather information.

    printcool("Gas phase molecular dynamics", color=4, bold=True)
    click()
    mprop_return = Gas.molecular_dynamics(**MDOpts["gas"])
    logger.info("Gas phase MD simulation took %.3f seconds\n" % click())
    mPotentials = mprop_return['Potentials']
    mKinetics = mprop_return['Kinetics']
    mEDA = mprop_return['Ecomps']

    mEnergies = mPotentials + mKinetics
    mEne_avg, mEne_err = mean_stderr(mEnergies)
    PrintEDA(mEDA, 1)

    #============================================#
    #  Compute the potential energy derivatives. #
    #============================================#
    logger.info("Calculating potential energy derivatives with finite difference step size: %f\n" % h)
    # Switch for whether to compute the derivatives two different ways for consistency.
    FDCheck = False

    # Create a double-precision simulation object if desired (seems unnecessary).
    DoublePrecisionDerivatives = False
    if engname == "openmm" and DoublePrecisionDerivatives and AGrad:
        logger.info("Creating Double Precision Simulation for parameter derivatives\n")
        Liquid = Engine(name="liquid", openmm_precision="double", **EngOpts["liquid"])
        Gas = Engine(name="gas", openmm_precision="double", **EngOpts["gas"])

    # Compute the energy and dipole derivatives.
    printcool("Condensed phase energy and dipole derivatives\nInitializing array to length %i" % len(Energies), color=4, bold=True)
    click()
    G, GDx, GDy, GDz = energy_derivatives(Liquid, FF, mvals, h, pgrad, len(Energies), AGrad, dipole=True)
    logger.info("Condensed phase energy derivatives took %.3f seconds\n" % click())
    click()
    printcool("Gas phase energy derivatives", color=4, bold=True)
    mG, _, __, ___ = energy_derivatives(Gas, FF, mvals, h, pgrad, len(mEnergies), AGrad, dipole=False)
    logger.info("Gas phase energy derivatives took %.3f seconds\n" % click())

    #==============================================#
    #  Condensed phase properties and derivatives. #
    #==============================================#

    #----
    # Density
    #----
    # Build the first density derivative.
    GRho = mBeta * (flat(np.dot(G, col(Rhos))) / L - np.mean(Rhos) * np.mean(G, axis=1))
    # Print out the density and its derivative.
    Sep = printcool("Density: % .4f +- % .4f kg/m^3\nAnalytic Derivative:" % (Rho_avg, Rho_err))
    FF.print_map(vals=GRho)
    logger.info(Sep)

    def calc_rho(b = None, **kwargs):
        if b is None: b = np.ones(L,dtype=float)
        if 'r_' in kwargs:
            r_ = kwargs['r_']
        return bzavg(r_,b)

    # No need to calculate error using bootstrap, but here it is anyway
    # Rhoboot = []
    # for i in range(numboots):
    #    boot = np.random.randint(N,size=N)
    #    Rhoboot.append(calc_rho(None,**{'r_':Rhos[boot]}))
    # Rhoboot = np.array(Rhoboot)
    # Rho_err = np.std(Rhoboot)

    if FDCheck:
        Sep = printcool("Numerical Derivative:")
        GRho1 = property_derivatives(Liquid, FF, mvals, h, pgrad, kT, calc_rho, {'r_':Rhos})
        FF.print_map(vals=GRho1)
        Sep = printcool("Difference (Absolute, Fractional):")
        absfrac = ["% .4e  % .4e" % (i-j, (i-j)/j) for i,j in zip(GRho, GRho1)]
        FF.print_map(vals=absfrac)

    #----
    # Enthalpy of vaporization
    #----
    H = Energies + pV
    V = np.array(Volumes)

    # Print out the liquid enthalpy.
    logger.info("Liquid enthalpy: % .4f kJ/mol, stdev % .4f ; (% .4f from energy, % .4f from pV)\n" % 
                (np.mean(H), np.std(H), np.mean(Energies), np.mean(pV)))
    numboots = 1000

    # The enthalpy of vaporization in kJ/mol.
    Hvap_avg = mEne_avg - Ene_avg / NMol + kT - np.mean(pV) / NMol
    Hvap_err = np.sqrt(Ene_err**2 / NMol**2 + mEne_err**2 + pV_err**2/NMol**2)

    # Build the first Hvap derivative.
    GHvap = np.mean(G,axis=1)
    GHvap += mBeta * (flat(np.dot(G, col(Energies))) / L - Ene_avg * np.mean(G, axis=1))
    GHvap /= NMol
    GHvap -= np.mean(mG,axis=1)
    GHvap -= mBeta * (flat(np.dot(mG, col(mEnergies))) / L - mEne_avg * np.mean(mG, axis=1))
    GHvap *= -1
    GHvap -= mBeta * (flat(np.dot(G, col(pV))) / L - np.mean(pV) * np.mean(G, axis=1)) / NMol

    Sep = printcool("Enthalpy of Vaporization: % .4f +- %.4f kJ/mol\nAnalytic Derivative:" % (Hvap_avg, Hvap_err))
    FF.print_map(vals=GHvap)

    # Define some things to make the analytic derivatives easier.
    Gbar = np.mean(G,axis=1)
    def deprod(vec):
        return flat(np.dot(G,col(vec)))/L
    def covde(vec):
        return flat(np.dot(G,col(vec)))/L - Gbar*np.mean(vec)
    def avg(vec):
        return np.mean(vec)

    #----
    # Thermal expansion coefficient
    #----
    def calc_alpha(b = None, **kwargs):
        if b is None: b = np.ones(L,dtype=float)
        if 'h_' in kwargs:
            h_ = kwargs['h_']
        if 'v_' in kwargs:
            v_ = kwargs['v_']
        return 1/(kT*T) * (bzavg(h_*v_,b)-bzavg(h_,b)*bzavg(v_,b))/bzavg(v_,b)
    Alpha = calc_alpha(None, **{'h_':H, 'v_':V})
    Alphaboot = []
    for i in range(numboots):
        boot = np.random.randint(L,size=L)
        Alphaboot.append(calc_alpha(None, **{'h_':H[boot], 'v_':V[boot]}))
    Alphaboot = np.array(Alphaboot)
    Alpha_err = np.std(Alphaboot) * max([np.sqrt(statisticalInefficiency(V)),np.sqrt(statisticalInefficiency(H))])

    # Thermal expansion coefficient analytic derivative
    GAlpha1 = -1 * Beta * deprod(H*V) * avg(V) / avg(V)**2
    GAlpha2 = +1 * Beta * avg(H*V) * deprod(V) / avg(V)**2
    GAlpha3 = deprod(V)/avg(V) - Gbar
    GAlpha4 = Beta * covde(H)
    GAlpha  = (GAlpha1 + GAlpha2 + GAlpha3 + GAlpha4)/(kT*T)
    Sep = printcool("Thermal expansion coefficient: % .4e +- %.4e K^-1\nAnalytic Derivative:" % (Alpha, Alpha_err))
    FF.print_map(vals=GAlpha)
    if FDCheck:
        GAlpha_fd = property_derivatives(Liquid, FF, mvals, h, pgrad, kT, calc_alpha, {'h_':H,'v_':V})
        Sep = printcool("Numerical Derivative:")
        FF.print_map(vals=GAlpha_fd)
        Sep = printcool("Difference (Absolute, Fractional):")
        absfrac = ["% .4e  % .4e" % (i-j, (i-j)/j) for i,j in zip(GAlpha, GAlpha_fd)]
        FF.print_map(vals=absfrac)

    #----
    # Isothermal compressibility
    #----
    def calc_kappa(b=None, **kwargs):
        if b is None: b = np.ones(L,dtype=float)
        if 'v_' in kwargs:
            v_ = kwargs['v_']
        return bar_unit / kT * (bzavg(v_**2,b)-bzavg(v_,b)**2)/bzavg(v_,b)
    Kappa = calc_kappa(None,**{'v_':V})
    Kappaboot = []
    for i in range(numboots):
        boot = np.random.randint(L,size=L)
        Kappaboot.append(calc_kappa(None,**{'v_':V[boot]}))
    Kappaboot = np.array(Kappaboot)
    Kappa_err = np.std(Kappaboot) * np.sqrt(statisticalInefficiency(V))

    # Isothermal compressibility analytic derivative
    Sep = printcool("Isothermal compressibility:  % .4e +- %.4e bar^-1\nAnalytic Derivative:" % (Kappa, Kappa_err))
    GKappa1 = +1 * Beta**2 * avg(V**2) * deprod(V) / avg(V)**2
    GKappa2 = -1 * Beta**2 * avg(V) * deprod(V**2) / avg(V)**2
    GKappa3 = +1 * Beta**2 * covde(V)
    GKappa  = bar_unit*(GKappa1 + GKappa2 + GKappa3)
    FF.print_map(vals=GKappa)
    if FDCheck:
        GKappa_fd = property_derivatives(Liquid, FF, mvals, h, pgrad, kT, calc_kappa, {'v_':V})
        Sep = printcool("Numerical Derivative:")
        FF.print_map(vals=GKappa_fd)
        Sep = printcool("Difference (Absolute, Fractional):")
        absfrac = ["% .4e  % .4e" % (i-j, (i-j)/j) for i,j in zip(GKappa, GKappa_fd)]
        FF.print_map(vals=absfrac)

    #----
    # Isobaric heat capacity
    #----
    def calc_cp(b=None, **kwargs):
        if b is None: b = np.ones(L,dtype=float)
        if 'h_' in kwargs:
            h_ = kwargs['h_']
        Cp_  = 1/(NMol*kT*T) * (bzavg(h_**2,b) - bzavg(h_,b)**2)
        Cp_ *= 1000 / 4.184
        return Cp_
    Cp = calc_cp(None,**{'h_':H})
    Cpboot = []
    for i in range(numboots):
        boot = np.random.randint(L,size=L)
        Cpboot.append(calc_cp(None,**{'h_':H[boot]}))
    Cpboot = np.array(Cpboot)
    Cp_err = np.std(Cpboot) * np.sqrt(statisticalInefficiency(H))

    # Isobaric heat capacity analytic derivative
    GCp1 = 2*covde(H) * 1000 / 4.184 / (NMol*kT*T)
    GCp2 = mBeta*covde(H**2) * 1000 / 4.184 / (NMol*kT*T)
    GCp3 = 2*Beta*avg(H)*covde(H) * 1000 / 4.184 / (NMol*kT*T)
    GCp  = GCp1 + GCp2 + GCp3
    Sep = printcool("Isobaric heat capacity:  % .4e +- %.4e cal mol-1 K-1\nAnalytic Derivative:" % (Cp, Cp_err))
    FF.print_map(vals=GCp)
    if FDCheck:
        GCp_fd = property_derivatives(Liquid, FF, mvals, h, pgrad, kT, calc_cp, {'h_':H})
        Sep = printcool("Numerical Derivative:")
        FF.print_map(vals=GCp_fd)
        Sep = printcool("Difference (Absolute, Fractional):")
        absfrac = ["% .4e  % .4e" % (i-j, (i-j)/j) for i,j in zip(GCp,GCp_fd)]
        FF.print_map(vals=absfrac)

    #----
    # Dielectric constant
    #----
    def calc_eps0(b=None, **kwargs):
        if b is None: b = np.ones(L,dtype=float)
        if 'd_' in kwargs: # Dipole moment vector.
            d_ = kwargs['d_']
        if 'v_' in kwargs: # Volume.
            v_ = kwargs['v_']
        b0 = np.ones(L,dtype=float)
        dx = d_[:,0]
        dy = d_[:,1]
        dz = d_[:,2]
        D2  = bzavg(dx**2,b)-bzavg(dx,b)**2
        D2 += bzavg(dy**2,b)-bzavg(dy,b)**2
        D2 += bzavg(dz**2,b)-bzavg(dz,b)**2
        return prefactor*D2/bzavg(v_,b)/T
    Eps0 = calc_eps0(None,**{'d_':Dips, 'v_':V})
    Eps0boot = []
    for i in range(numboots):
        boot = np.random.randint(L,size=L)
        Eps0boot.append(calc_eps0(None,**{'d_':Dips[boot], 'v_':V[boot]}))
    Eps0boot = np.array(Eps0boot)
    Eps0_err = np.std(Eps0boot)*np.sqrt(np.mean([statisticalInefficiency(Dips[:,0]),statisticalInefficiency(Dips[:,1]),statisticalInefficiency(Dips[:,2])]))
 
    # Dielectric constant analytic derivative
    Dx = Dips[:,0]
    Dy = Dips[:,1]
    Dz = Dips[:,2]
    D2 = avg(Dx**2)+avg(Dy**2)+avg(Dz**2)-avg(Dx)**2-avg(Dy)**2-avg(Dz)**2
    GD2  = 2*(flat(np.dot(GDx,col(Dx)))/L - avg(Dx)*(np.mean(GDx,axis=1))) - Beta*(covde(Dx**2) - 2*avg(Dx)*covde(Dx))
    GD2 += 2*(flat(np.dot(GDy,col(Dy)))/L - avg(Dy)*(np.mean(GDy,axis=1))) - Beta*(covde(Dy**2) - 2*avg(Dy)*covde(Dy))
    GD2 += 2*(flat(np.dot(GDz,col(Dz)))/L - avg(Dz)*(np.mean(GDz,axis=1))) - Beta*(covde(Dz**2) - 2*avg(Dz)*covde(Dz))
    GEps0 = prefactor*(GD2/avg(V) - mBeta*covde(V)*D2/avg(V)**2)/T
    Sep = printcool("Dielectric constant:           % .4e +- %.4e\nAnalytic Derivative:" % (Eps0, Eps0_err))
    FF.print_map(vals=GEps0)
    if FDCheck:
        GEps0_fd = property_derivatives(Liquid, FF, mvals, h, pgrad, kT, calc_eps0, {'d_':Dips,'v_':V})
        Sep = printcool("Numerical Derivative:")
        FF.print_map(vals=GEps0_fd)
        Sep = printcool("Difference (Absolute, Fractional):")
        absfrac = ["% .4e  % .4e" % (i-j, (i-j)/j) for i,j in zip(GEps0,GEps0_fd)]
        FF.print_map(vals=absfrac)

    logger.info("Writing final force field.\n")
    pvals = FF.make(mvals)

    logger.info("Writing all simulation data to disk.\n")
    lp_dump((Rhos, Volumes, Potentials, Energies, Dips, G, [GDx, GDy, GDz], mPotentials, mEnergies, mG, Rho_err, Hvap_err, Alpha_err, Kappa_err, Cp_err, Eps0_err, NMol),'npt_result.p')

if __name__ == "__main__":
    main()
