def normalizehift(in_equations):
''' Normalizes equations by shuffeling terms around \n
can handel LOG, DLOG and DIF in the left hans side of = '''
nymodel=[]
equations=in_equations[:] # we want do change the e
# modelprint(equations)
for comment,command,value in find_statements(equations.upper()):
# print('>>',comment,'<',command,'>',value)
if comment:
nymodel.append(comment)
elif command=='FRML':
a,fr,n,udtryk=split_frml((command+' '+value).upper())
lhs,rhs=udtryk.split('=',1)
lhsterms=udtryk_parse(lhs,funks=funks)
if len(lhsterms) == 1: # only one term on the left hand side, no need to shuffel around
pass
elif len(lhsterms) == 4: # We need to normalixe expect funk(x) on the levt hand side funk=LOG,DLOG or DIFF
rhs=rhs[:-1].strip() # discharge the $ strip blanks for nice look
lhs=lhsterms[2].var # name of the dependent variablem, no syntax check here
if lhsterms[0].op == 'LOG':
rhs='EXP('+rhs+')'
udtryk=lhs+'='+rhs+'$' # now the equation is normalized
elif lhsterms[0].op == 'DIFF':
rhs=lagone(lhs,funks=funks)+'+('+rhs+')'
udtryk=lhs+'='+rhs+'$' # now the equation is normalized
elif lhsterms[0].op == 'DLOG':
rhs='EXP(LOG('+lagone(lhs,funks=funks)+')+'+rhs+')'
udtryk=lhs+'='+rhs+'$' # now the equation is normalized
elif lhsterms[0].op == 'LOGIT':
rhs='(exp('+rhs+')/(1+EXP('+rhs+')))'
udtryk=lhs+'='+rhs+'$' # now the equation is normalized
# else:
# print('*** ERROR operand not allowed left of =',lhs)
# print(lhsterms)
else:
pass
# print('*** Try to normalize relation for:',lhs)
# now the right hand side is expanded for DLOG and DIFF
while 'DLOG(' in udtryk.upper():
fordlog,dlogudtryk,efterdlog=find_arg('dlog',udtryk)
udtryk=fordlog+'diff(log('+dlogudtryk+'))'+efterdlog
while 'DIFF(' in udtryk.upper():
fordif,difudtryk,efterdif=find_arg('diff',udtryk)
udtryk=fordif+'(('+difudtryk+')-('+lagone(difudtryk+'',funks=funks)+'))'+efterdif
nymodel.append(command+' '+n+' '+udtryk)
else:
nymodel.append(command+' '+value)
equations='\n'.join(nymodel)
# modelprint(in_equations,'Before normalization and expansion')
# modelprint(equations, 'After normalization and expansion')
return equations
def pastestring(ind,post,funks=[]):
''' All variable names in a in a string **ind** is pasted with the string **post**
This function can be used to awoid variable name conflict with the internal variable names in sympy.
an advanced function
'''
nt=udtryk_parse(ind,funks=funks)
fib=[]
for t in nt:
if t.op:
ud=t.op
elif t.number:
ud=t.number
elif t.var:
ud= t.var+ post+ ('('+(str(int(t.lag)))+')' if t.lag else '')
fib.append(ud)
return ''.join(fib)
def lagone(ind, funks=[]):
''' All variables in a string i
s lagged one more time '''
nt = udtryk_parse(ind, funks=funks)
fib = []
for t in nt:
if t.op:
ud = t.op
elif t.number:
ud = t.number
elif t.var:
lag = t.lag if t.lag else '0'
org_lag = int(lag)
new_lag = org_lag - 1
if lag == '+1':
ud = t.var
else:
ud = t.var + f'({new_lag:+})'
fib.append(ud)
return ''.join(fib)
def stripstring(ind,post,funks=[]):
''' All variable names in a in a string is **ind** is stripped of the string **post**.
This function reverses the pastestring process
'''
nt=udtryk_parse(ind,funks=funks)
fib=[]
lenpost=len(post)
for t in nt:
if t.op:
ud=t.op
elif t.number:
ud=t.number
elif t.var:
if t.var.endswith(post.upper()):
ud= t.var[:-lenpost]+ ('('+(str(int(t.lag)))+')' if t.lag else '')
else:
print('Tryes to strip '+post +' from '+ind)
fib.append(ud)
return ''.join(fib)
def findendo(ind):
''' finds the equation for the first variable of a string'''
def endovar(f): # Finds the first variable in a expression
for t in udtryk_parse(f,funks=funks):
if t.var:
ud=t.var
break
return ud
ind=re.sub(r'LOG\(','log(',ind) # sypy uses lover case for log and exp
ind=re.sub(r'EXP\(','exp(',ind)
lhs,rhs=ind.split('=',1)
if len(udtryk_parse(lhs,funks=funks)) >=2: # we have an expression on the left hand side
# print('Before >>',ind)
endo=sympify(endovar(lhs))
kat=sympify('Eq('+lhs+','+rhs[0:-1]+')') # we take the the $ out
endo_frml=solve(kat,endo,simplify=False,rational=False)
# print('After >>', str(endo)+'=' + str(endo_frml[0])+'$')
return str(endo)+'=' + str(endo_frml[0])+'$'
else: # no need to solve this equation
return ind
def an_expression_to_latex(exp,funks=[]):
''' Returns a latex string from a list of terms (defined in the modelpattern module)
funks is a list of localy defines functions
'''
def t_to_latex(t):
if t.var:
var =vtol(t.var)
if t.lag:
return f'{var}_{{t{t.lag}}}'
else:
return f'{var}_t'
elif t.number:
return t.number
else:
if t.op == '*':
op=r'\times'
elif t.op == '$':
op=''
else:
op = t.op
return op
return ' '.join([t_to_latex(t) for t in pt.udtryk_parse(exp,funks=funks)])
# -*- coding: utf-8 -*-
import modelpattern as mp
import re
def f(a):
return a * 2
def t_to_latex(t):
if t.var:
var = re.sub(r'_', r'\_', t.var)
if t.lag:
return f'{var}_{{t{t.lag}}}'
else:
return f'{var}_t'
elif t.number:
return t.number
else:
return t.op.lower()
p = mp.udtryk_parse('a+b__e+d(-1)+g(+1)+f(3) ', funks=[f])
temp = ' '.join([t_to_latex(t) for t in p])
def endovar(f): # Finds the first variable in a expression
for t in udtryk_parse(f, funks=funks):
if t.var:
ud = t.var
break
return ud