source: TOOLS/WATER_BUDGET/WaterUtils.py @ 6508

#!/usr/bin/env python3
###
### Script to check water conservation in the IPSL coupled model
###
## Here, some common utilities to all scripts
##
##  Warning, to install, configure, run, use any of included software or
##  to read the associated documentation you'll need at least one (1)
##  brain in a reasonably working order. Lack of this implement will
##  void any warranties (either express or implied).  Authors assumes
##  no responsability for errors, omissions, data loss, or any other
##  consequences caused directly or indirectly by the usage of his
##  software by incorrectly or partially configured personal
##
##
## SVN information
#  $Author: omamce $
#  $Date: 2022-12-08 10:24:05 +0100 (Thu, 08 Dec 2022) $
#  $Revision: 6277 $
#  $Id: ATM_waterbudget.py 6277 2022-12-08 09:24:05Z omamce $
#  $HeadURL: svn+ssh://omamce@forge.ipsl.jussieu.fr/ipsl/forge/projets/igcmg/svn/TOOLS/WATER_BUDGET/ATM_waterbudget.py $

## Import system modules
#import sys, os, shutil, subprocess, platform
import numpy as np
import configparser, re

VarInt = 10
Ra     = None

def ftest () :
    print ( toto )

def setBool (chars) :
    '''Convert specific char string in boolean if possible'''
    setBool = chars
    if type (chars) == str :
        for key in configparser.ConfigParser.BOOLEAN_STATES.keys () :
            if chars.lower() == key : setBool = configparser.ConfigParser.BOOLEAN_STATES[key]
    return setBool

def setNum (chars) :
    '''Convert specific char string in integer or real if possible'''
    if type (chars) == str :
        realnum = re.compile ("^[-+]?[0-9]*\.?[0-9]+(e[-+]?[0-9]+)?$")
        isNumber = realnum.match(chars.strip()) != None
        isInt    = chars.strip().isdigit()
        #print (chars , isNumber , isInt)
        if isNumber :
            if isInt : setNum = int   (chars)
            else     : setNum = float (chars)
        else : setNum = chars
    else : setNum = chars
    return setNum

def setNone (chars) :
    '''Convert specific char string to None if possible'''
    if type (chars) == str :
        if chars in ['None', 'NONE', 'none'] : setNone = None
        else : setNone = chars
    else : setNone = chars
    return setNone

def unDefined (char) :
    if char in globals () :
        if globals()[char] == None : unDefined = True
        else            : unDefined = False
    else                : unDefined = True
    return unDefined

def Ksum (tab) :
    '''
    Kahan summation algorithm, also known as compensated summation
    https://en.wikipedia.org/wiki/Kahan_summation_algorithm
    '''
    Ksum = 0.0                   # Prepare the accumulator.
    comp = 0.0                   # A running compensation for lost low-order bits.
   
    for xx in np.where ( np.isnan(tab), 0., tab ) : 
        yy = xx - comp           # comp is zero the first time around.
        tt = Ksum + yy           # Alas, sum is big, y small, so low-order digits of y are lost.
        comp = (tt - Ksum) - yy  # (tt - Ksum) cancels the high-order part of y; subtracting y recovers negative (low part of yy)
        Ksum = tt                # Algebraically, comp should always be zero. Beware overly-aggressive optimizing compilers !
                                 # Next time around, the lost low part will be added to y in a fresh attempt.
    return Ksum

def Ssum (tab) :
    '''
    Precision summation by sorting by absolute value
    '''
    Ssum = np.sum ( tab[np.argsort(np.abs(tab))] )
    return Ssum

def KSsum (tab) :
    '''
    Precision summation by sorting by absolute value, and applying Kahan summation
    '''
    KSsum = Ksum ( tab[np.argsort(np.abs(tab))] )
    return KSsum

# Choosing algorithm for precise summation
Psum = KSsum