[sympy] Re: pattern replacement for complex numbers and manual factorization
As you have a string representation of your object, a non-sympy way is by
using string regex:
In [1]: expr = eval(Add(Mul(Integer(-1), Integer(2), Symbol('g'),
Symbol('psi^ss_1'), conjugate(Symbol('psi^ss_1'))), Mul(Integer(-1),
Integer(2), Symbol('g'), Symbol('psi^ss_2'),
conjugate(Symbol('psi^ss_2'))), Symbol('omega_2'), Mul(Integer(-1),
Rational(1, 2), Pow(Symbol('m'), Integer(-1)), Pow(Add(Mul(Integer(-1),
Symbol('k')), Symbol('k_2')), Integer(2)
In [2]: expr
Out[2]:
2
___ ___(-k + k₂)
- 2⋅g⋅ψ_1__ss⋅ψ_1__ss - 2⋅g⋅ψ_2__ss⋅ψ_2__ss + ω₂ - ──
2⋅m
In [3]: import re
In [4]: eval(re.sub(r(?PquoteSymbol\('[^']+'\)),
+conjugate\((?P=quote)\), rabs(\1)**2, srepr(expr)))
Out[4]:
2
22(-k + k₂)
- 2⋅g⋅│ψ_1__ss│ - 2⋅g⋅│ψ_2__ss│ + ω₂ - ──
2⋅m
SymPy also has its own system of pattern matching, but it looks like it
needs to match whole expressions.
On Thursday, June 5, 2014 11:48:17 PM UTC+2, Andrei Berceanu wrote:
I have the following expression in sympy:
Add(Mul(Integer(-1), Integer(2), Symbol('g'), Symbol('psi^ss_1'),
conjugate(Symbol('psi^ss_1'))), Mul(Integer(-1), Integer(2), Symbol('g'),
Symbol('psi^ss_2'), conjugate(Symbol('psi^ss_2'))), Symbol('omega_2'),
Mul(Integer(-1), Rational(1, 2), Pow(Symbol('m'), Integer(-1)),
Pow(Add(Mul(Integer(-1), Symbol('k')), Symbol('k_2')), Integer(2
(sorry for the long line, didnt know how else to paste it)
Anyway, I would like to factor 2g in front of the 2 terms that contain it
(simplify doesnt do it for some reason) and also would like to replace all
occurrences of x*conjugate(x) by abs(x)**2. There are two such occurrences
and I tried to do expr.replace(a*conjugate(a), abs(a)**2) without any luck.
Could anyone please help?
Tnx,
Andrei
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[sympy] Re: pattern replacement for complex numbers and manual factorization
A better alternative:
In [1]: from sympy import *
In [2]: expr = eval(Add(Mul(Integer(-1), Integer(2), Symbol('g'),
Symbol('psi^ss_1'), conjugate(Symbol('psi^ss_1'))), Mul(Integer(-1),
Integer(2), Symbol('g'), Symbol('psi^ss_2'),
conjugate(Symbol('psi^ss_2'))), Symbol('omega_2'), Mul(Integer(-1),
Rational(1, 2), Pow(Symbol('m'), Integer(-1)), Pow(Add(Mul(Integer(-1),
Symbol('k')), Symbol('k_2')), Integer(2)
In [3]: from sympy.strategies.traverse import bottom_up
In [4]: from sympy.strategies import chain, rebuild
In [5]: def to_abs (node ):
...: if not isinstance(node, Mul):
...: return node
...: z = Wild ('z')
...: w = Wild ('w')
...: m = node .match (z * w *conjugate (w))
...: if w in m:
...: e =m[w]
...: return node.xreplace ({e: S.One, conjugate(e): S.One
})*abs(e)**2)
...: return node
...:
In [6]: bottom_up(chain(rebuild, to_abs))(expr)
Out[6]:
2
22(k + k₂)
- 2⋅g⋅│ψ_1__ss│ - 2⋅g⋅│ψ_2__ss│ + ω₂ + ─
4⋅m
On Friday, June 6, 2014 9:13:15 AM UTC+2, F. B. wrote:
As you have a string representation of your object, a non-sympy way is by
using string regex:
In [1]: expr = eval(Add(Mul(Integer(-1), Integer(2), Symbol('g'),
Symbol('psi^ss_1'), conjugate(Symbol('psi^ss_1'))), Mul(Integer(-1),
Integer(2), Symbol('g'), Symbol('psi^ss_2'),
conjugate(Symbol('psi^ss_2'))), Symbol('omega_2'), Mul(Integer(-1),
Rational(1, 2), Pow(Symbol('m'), Integer(-1)), Pow(Add(Mul(Integer(-1),
Symbol('k')), Symbol('k_2')), Integer(2)
In [2]: expr
Out[2]:
2
___ ___(-k + k₂)
- 2⋅g⋅ψ_1__ss⋅ψ_1__ss - 2⋅g⋅ψ_2__ss⋅ψ_2__ss + ω₂ - ──
2⋅m
In [3]: import re
In [4]: eval(re.sub(r(?PquoteSymbol\('[^']+'\)),
+conjugate\((?P=quote)\), rabs(\1)**2, srepr(expr)))
Out[4]:
2
22(-k + k₂)
- 2⋅g⋅│ψ_1__ss│ - 2⋅g⋅│ψ_2__ss│ + ω₂ - ──
2⋅m
SymPy also has its own system of pattern matching, but it looks like it
needs to match whole expressions.
On Thursday, June 5, 2014 11:48:17 PM UTC+2, Andrei Berceanu wrote:
I have the following expression in sympy:
Add(Mul(Integer(-1), Integer(2), Symbol('g'), Symbol('psi^ss_1'),
conjugate(Symbol('psi^ss_1'))), Mul(Integer(-1), Integer(2), Symbol('g'),
Symbol('psi^ss_2'), conjugate(Symbol('psi^ss_2'))), Symbol('omega_2'),
Mul(Integer(-1), Rational(1, 2), Pow(Symbol('m'), Integer(-1)),
Pow(Add(Mul(Integer(-1), Symbol('k')), Symbol('k_2')), Integer(2
(sorry for the long line, didnt know how else to paste it)
Anyway, I would like to factor 2g in front of the 2 terms that contain it
(simplify doesnt do it for some reason) and also would like to replace all
occurrences of x*conjugate(x) by abs(x)**2. There are two such occurrences
and I tried to do expr.replace(a*conjugate(a), abs(a)**2) without any luck.
Could anyone please help?
Tnx,
Andrei
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[sympy] Re: New user question: Expanding quotients of complex numbers
On Friday, June 6, 2014 2:36:34 AM UTC+2, jeanbi...@gmail.com wrote:
var('A,B,C,D,u,v,qi,qf')
qi = 1/(u-I*v)
qf = (A+B/qi)/(C+D/qi)
First of all, you don't need to declare *qi* and *qf* in var( ... ),
because they get overwritten in the next expressions.
By the way, maybe you mean that A, B, C, D, u, v are real? What about this:
var('A,B,C,D,u,v', real=True)
expand(1/qf, complex=True) looks much nicer.
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[sympy] Re: pattern replacement for complex numbers and manual factorization
Tnx!
I think there is an error in the line (unbalanced paranthesis):
return node.xreplace ({e: S.One, conjugate(e): S.One})*abs(e)**2)
Also, do you know how I can force the factorization of the 2*g to get
2*g(|psi1|**2 + |psi2|**2)?
On Friday, June 6, 2014 10:45:37 AM UTC+2, F. B. wrote:
A better alternative:
In [1]: from sympy import *
In [2]: expr = eval(Add(Mul(Integer(-1), Integer(2), Symbol('g'),
Symbol('psi^ss_1'), conjugate(Symbol('psi^ss_1'))), Mul(Integer(-1),
Integer(2), Symbol('g'), Symbol('psi^ss_2'),
conjugate(Symbol('psi^ss_2'))), Symbol('omega_2'), Mul(Integer(-1),
Rational(1, 2), Pow(Symbol('m'), Integer(-1)), Pow(Add(Mul(Integer(-1),
Symbol('k')), Symbol('k_2')), Integer(2)
In [3]: from sympy.strategies.traverse import bottom_up
In [4]: from sympy.strategies import chain, rebuild
In [5]: def to_abs (node ):
...: if not isinstance(node, Mul):
...: return node
...: z = Wild ('z')
...: w = Wild ('w')
...: m = node .match (z * w *conjugate (w))
...: if w in m:
...: e =m[w]
...: return node.xreplace ({e: S.One, conjugate(e): S.
One})*abs(e)**2)
...: return node
...:
In [6]: bottom_up(chain(rebuild, to_abs))(expr)
Out[6]:
2
22(k + k₂)
- 2⋅g⋅│ψ_1__ss│ - 2⋅g⋅│ψ_2__ss│ + ω₂ + ─
4⋅m
On Friday, June 6, 2014 9:13:15 AM UTC+2, F. B. wrote:
As you have a string representation of your object, a non-sympy way is by
using string regex:
In [1]: expr = eval(Add(Mul(Integer(-1), Integer(2), Symbol('g'),
Symbol('psi^ss_1'), conjugate(Symbol('psi^ss_1'))), Mul(Integer(-1),
Integer(2), Symbol('g'), Symbol('psi^ss_2'),
conjugate(Symbol('psi^ss_2'))), Symbol('omega_2'), Mul(Integer(-1),
Rational(1, 2), Pow(Symbol('m'), Integer(-1)), Pow(Add(Mul(Integer(-1),
Symbol('k')), Symbol('k_2')), Integer(2)
In [2]: expr
Out[2]:
2
___ ___(-k + k₂)
- 2⋅g⋅ψ_1__ss⋅ψ_1__ss - 2⋅g⋅ψ_2__ss⋅ψ_2__ss + ω₂ - ──
2⋅m
In [3]: import re
In [4]: eval(re.sub(r(?PquoteSymbol\('[^']+'\)),
+conjugate\((?P=quote)\), rabs(\1)**2, srepr(expr)))
Out[4]:
2
22(-k + k₂)
- 2⋅g⋅│ψ_1__ss│ - 2⋅g⋅│ψ_2__ss│ + ω₂ - ──
2⋅m
SymPy also has its own system of pattern matching, but it looks like it
needs to match whole expressions.
On Thursday, June 5, 2014 11:48:17 PM UTC+2, Andrei Berceanu wrote:
I have the following expression in sympy:
Add(Mul(Integer(-1), Integer(2), Symbol('g'), Symbol('psi^ss_1'),
conjugate(Symbol('psi^ss_1'))), Mul(Integer(-1), Integer(2), Symbol('g'),
Symbol('psi^ss_2'), conjugate(Symbol('psi^ss_2'))), Symbol('omega_2'),
Mul(Integer(-1), Rational(1, 2), Pow(Symbol('m'), Integer(-1)),
Pow(Add(Mul(Integer(-1), Symbol('k')), Symbol('k_2')), Integer(2
(sorry for the long line, didnt know how else to paste it)
Anyway, I would like to factor 2g in front of the 2 terms that contain
it (simplify doesnt do it for some reason) and also would like to replace
all occurrences of x*conjugate(x) by abs(x)**2. There are two such
occurrences and I tried to do expr.replace(a*conjugate(a), abs(a)**2)
without any luck.
Could anyone please help?
Tnx,
Andrei
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[sympy] Re: pattern replacement for complex numbers and manual factorization
On Friday, June 6, 2014 12:22:14 PM UTC+2, Andrei Berceanu wrote:
Tnx!
I think there is an error in the line (unbalanced paranthesis):
return node.xreplace ({e: S.One, conjugate(e): S.One})*abs(e)**2)
Yes, sorry, just remove the last parenthesis.
Also, do you know how I can force the factorization of the 2*g to get
2*g(|psi1|**2 + |psi2|**2)?
Try this one:
import collections
def unflatten_mul(node):
d = collections.defaultdict(lambda: [])
new_args = []
for arg in node.args:
if arg.args and arg.args[0].is_Number:
d[arg.args[0]].append(arg.func(*arg.args[1:]))
continue
new_args.append(arg)
print d
for key, item in d.items():
new_args.append(Mul(key, Add(*item), evaluate=False))
return node.func(*new_args, evaluate=False)
apply this function on *expr*, it should work.
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[sympy] Re: pattern replacement for complex numbers and manual factorization
That fixed the error, however, the problem is now if I apply this function
to expressions like
-2*g*conjugate(psi^ss_1)*conjugate(psi^ss_2)
I get
-2*g*conjugate(psi^ss_1)*Abs(psi^ss_2)**2
so it looks like the pattern matching is working overtime, since it should
leave the expression unchanged :)
On Friday, June 6, 2014 1:07:26 PM UTC+2, F. B. wrote:
On Friday, June 6, 2014 12:22:14 PM UTC+2, Andrei Berceanu wrote:
Tnx!
I think there is an error in the line (unbalanced paranthesis):
return node.xreplace ({e: S.One, conjugate(e): S.One})*abs(e)**2)
Yes, sorry, just remove the last parenthesis.
Also, do you know how I can force the factorization of the 2*g to get
2*g(|psi1|**2 + |psi2|**2)?
Try this one:
import collections
def unflatten_mul(node):
d = collections.defaultdict(lambda: [])
new_args = []
for arg in node.args:
if arg.args and arg.args[0].is_Number:
d[arg.args[0]].append(arg.func(*arg.args[1:]))
continue
new_args.append(arg)
print d
for key, item in d.items():
new_args.append(Mul(key, Add(*item), evaluate=False))
return node.func(*new_args, evaluate=False)
apply this function on *expr*, it should work.
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[sympy] Re: pattern replacement for complex numbers and manual factorization
The unflatten_mul function factorized the 2, but not the g, i.e. it returns
2(g*|psi1|**2 + g*|psi2|**2)
instead of
2g*(|psi1|**2 + |psi2|**2)
On Friday, June 6, 2014 1:07:26 PM UTC+2, F. B. wrote:
On Friday, June 6, 2014 12:22:14 PM UTC+2, Andrei Berceanu wrote:
Tnx!
I think there is an error in the line (unbalanced paranthesis):
return node.xreplace ({e: S.One, conjugate(e): S.One})*abs(e)**2)
Yes, sorry, just remove the last parenthesis.
Also, do you know how I can force the factorization of the 2*g to get
2*g(|psi1|**2 + |psi2|**2)?
Try this one:
import collections
def unflatten_mul(node):
d = collections.defaultdict(lambda: [])
new_args = []
for arg in node.args:
if arg.args and arg.args[0].is_Number:
d[arg.args[0]].append(arg.func(*arg.args[1:]))
continue
new_args.append(arg)
print d
for key, item in d.items():
new_args.append(Mul(key, Add(*item), evaluate=False))
return node.func(*new_args, evaluate=False)
apply this function on *expr*, it should work.
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Re: [sympy] Re: pattern replacement for complex numbers and manual factorization
Hello.
All the receipts in this dicussion look very interesting.Maybe all of this
ones could be put in the official documentation.
Christophe BAL
2014-06-06 13:34 GMT+02:00 Andrei Berceanu andreiberce...@gmail.com:
The unflatten_mul function factorized the 2, but not the g, i.e. it returns
2(g*|psi1|**2 + g*|psi2|**2)
instead of
2g*(|psi1|**2 + |psi2|**2)
On Friday, June 6, 2014 1:07:26 PM UTC+2, F. B. wrote:
On Friday, June 6, 2014 12:22:14 PM UTC+2, Andrei Berceanu wrote:
Tnx!
I think there is an error in the line (unbalanced paranthesis):
return node.xreplace ({e: S.One, conjugate(e): S.One})*abs(e)**2)
Yes, sorry, just remove the last parenthesis.
Also, do you know how I can force the factorization of the 2*g to get
2*g(|psi1|**2 + |psi2|**2)?
Try this one:
import collections
def unflatten_mul(node):
d = collections.defaultdict(lambda: [])
new_args = []
for arg in node.args:
if arg.args and arg.args[0].is_Number:
d[arg.args[0]].append(arg.func(*arg.args[1:]))
continue
new_args.append(arg)
print d
for key, item in d.items():
new_args.append(Mul(key, Add(*item), evaluate=False))
return node.func(*new_args, evaluate=False)
apply this function on *expr*, it should work.
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Re: [sympy] Re: pattern replacement for complex numbers and manual factorization
I agree, this could be helpful to many people. But first let's make sure we
iron out all the bugs.
And then I suppose one could re-write the expressions in a more
user-friendly form?
What do you propose, Chris?
On Friday, June 6, 2014 2:16:15 PM UTC+2, Christophe Bal wrote:
Hello.
All the receipts in this dicussion look very interesting.Maybe all of this
ones could be put in the official documentation.
Christophe BAL
2014-06-06 13:34 GMT+02:00 Andrei Berceanu andreib...@gmail.com
javascript::
The unflatten_mul function factorized the 2, but not the g, i.e. it
returns
2(g*|psi1|**2 + g*|psi2|**2)
instead of
2g*(|psi1|**2 + |psi2|**2)
On Friday, June 6, 2014 1:07:26 PM UTC+2, F. B. wrote:
On Friday, June 6, 2014 12:22:14 PM UTC+2, Andrei Berceanu wrote:
Tnx!
I think there is an error in the line (unbalanced paranthesis):
return node.xreplace ({e: S.One, conjugate(e): S.One})*abs(e)**2)
Yes, sorry, just remove the last parenthesis.
Also, do you know how I can force the factorization of the 2*g to get
2*g(|psi1|**2 + |psi2|**2)?
Try this one:
import collections
def unflatten_mul(node):
d = collections.defaultdict(lambda: [])
new_args = []
for arg in node.args:
if arg.args and arg.args[0].is_Number:
d[arg.args[0]].append(arg.func(*arg.args[1:]))
continue
new_args.append(arg)
print d
for key, item in d.items():
new_args.append(Mul(key, Add(*item), evaluate=False))
return node.func(*new_args, evaluate=False)
apply this function on *expr*, it should work.
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.
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[sympy] Re: pattern replacement for complex numbers and manual factorization
Try to use this one:
from sympy.unify import unify
def to_abs(node):
if not isinstance(node, Mul):
return node
zm1, zm2 = symbols('zm1, zm2')
m = unify(node, zm1 * zm2 * conjugate(zm2), {}, variables=[zm1, zm2])
try:
m = next(m)
except:
return node
e = m[zm2]
return node.xreplace({e: S.One, conjugate(e): S.One})*abs(e)**2
I believe that the standard matcher matches too much, let's try the unify
matcher, which is a structural matcher (and not a math-sensitive matcher).
On Friday, June 6, 2014 1:22:59 PM UTC+2, Andrei Berceanu wrote:
That fixed the error, however, the problem is now if I apply this
function to expressions like
-2*g*conjugate(psi^ss_1)*conjugate(psi^ss_2)
I get
-2*g*conjugate(psi^ss_1)*Abs(psi^ss_2)**2
so it looks like the pattern matching is working overtime, since it should
leave the expression unchanged :)
On Friday, June 6, 2014 1:07:26 PM UTC+2, F. B. wrote:
On Friday, June 6, 2014 12:22:14 PM UTC+2, Andrei Berceanu wrote:
Tnx!
I think there is an error in the line (unbalanced paranthesis):
return node.xreplace ({e: S.One, conjugate(e): S.One})*abs(e)**2)
Yes, sorry, just remove the last parenthesis.
Also, do you know how I can force the factorization of the 2*g to get
2*g(|psi1|**2 + |psi2|**2)?
Try this one:
import collections
def unflatten_mul(node):
d = collections.defaultdict(lambda: [])
new_args = []
for arg in node.args:
if arg.args and arg.args[0].is_Number:
d[arg.args[0]].append(arg.func(*arg.args[1:]))
continue
new_args.append(arg)
print d
for key, item in d.items():
new_args.append(Mul(key, Add(*item), evaluate=False))
return node.func(*new_args, evaluate=False)
apply this function on *expr*, it should work.
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[sympy] Re: pattern replacement for complex numbers and manual factorization
On Friday, June 6, 2014 1:34:04 PM UTC+2, Andrei Berceanu wrote: The unflatten_mul function factorized the 2, but not the g, i.e. it returns 2(g*|psi1|**2 + g*|psi2|**2) instead of 2g*(|psi1|**2 + |psi2|**2) Try to do so: def get_unflattener(m): m_args = list(m.args) def unflattener(node): new_args = [] sub_add_args = [] for arg in node.args: common = [i for i in arg.args if i in m_args] if set(common) == set(m_args): sub_add_args.append(arg) else: new_args.append(arg) sub_add = Add(*[i.func(*[j for j in i.args if j not in m_args]) for i in sub_add_args], evaluate=False) return Add(*(new_args + [Mul(*(m_args + [sub_add]), evaluate =False)]), evaluate=False) return unflattener get_unflattener(-2*g)(expr) -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/2e010cf4-7827-4d8c-9fe9-c485e0b77710%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Re: pattern replacement for complex numbers and manual factorization
I have no special ideas to propose except to start with the examples in
this discussion. Maybe different working methods can be shown.
2014-06-06 14:23 GMT+02:00 Andrei Berceanu andreiberce...@gmail.com:
I agree, this could be helpful to many people. But first let's make sure
we iron out all the bugs.
And then I suppose one could re-write the expressions in a more
user-friendly form?
What do you propose, Chris?
On Friday, June 6, 2014 2:16:15 PM UTC+2, Christophe Bal wrote:
Hello.
All the receipts in this dicussion look very interesting.Maybe all of
this ones could be put in the official documentation.
Christophe BAL
2014-06-06 13:34 GMT+02:00 Andrei Berceanu andreib...@gmail.com:
The unflatten_mul function factorized the 2, but not the g, i.e. it
returns
2(g*|psi1|**2 + g*|psi2|**2)
instead of
2g*(|psi1|**2 + |psi2|**2)
On Friday, June 6, 2014 1:07:26 PM UTC+2, F. B. wrote:
On Friday, June 6, 2014 12:22:14 PM UTC+2, Andrei Berceanu wrote:
Tnx!
I think there is an error in the line (unbalanced paranthesis):
return node.xreplace ({e: S.One, conjugate(e): S.One})*abs(e)**2)
Yes, sorry, just remove the last parenthesis.
Also, do you know how I can force the factorization of the 2*g to get
2*g(|psi1|**2 + |psi2|**2)?
Try this one:
import collections
def unflatten_mul(node):
d = collections.defaultdict(lambda: [])
new_args = []
for arg in node.args:
if arg.args and arg.args[0].is_Number:
d[arg.args[0]].append(arg.func(*arg.args[1:]))
continue
new_args.append(arg)
print d
for key, item in d.items():
new_args.append(Mul(key, Add(*item), evaluate=False))
return node.func(*new_args, evaluate=False)
apply this function on *expr*, it should work.
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Re: [sympy] Re: pattern replacement for complex numbers and manual factorization
I think that SymPy needs a better term rewriting system. And also a better pattern matcher. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/2e994baf-496e-4e9d-85f7-644c6a2fce08%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Re: pattern replacement for complex numbers and manual factorization
A easy to use treeview will be a great tool. No ? 2014-06-06 19:52 GMT+02:00 F. B. franz.bona...@gmail.com: I think that SymPy needs a better term rewriting system. And also a better pattern matcher. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/2e994baf-496e-4e9d-85f7-644c6a2fce08%40googlegroups.com . For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAAb4jGkhPCCRvw0iJgZ1k%2B0hsxCC9iy8Z6FPhgcAEaCBWWkh6A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Re: pattern replacement for complex numbers and manual factorization
Well yes, but that doesn´t change the fact that in Mathematica I can just do
expr /.{x_*Conj[x_] - Abs[x]^2}
and it just works!
On Friday, June 6, 2014 8:59:56 PM UTC+2, Christophe Bal wrote:
A easy to use treeview will be a great tool. No ?
2014-06-06 19:52 GMT+02:00 F. B. franz@gmail.com javascript::
I think that SymPy needs a better term rewriting system. And also a
better pattern matcher.
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Re: [sympy] Re: pattern replacement for complex numbers and manual factorization
By the way, I just found another case where the modulus value squared
substitution fails:
a, b, c, d = symbols('a b c d')
expr = a*b*conjugate(a)*conjugate(b) + c*d*conjugate(c)*conjugate(d)
bottom_up(chain(rebuild, to_abs))(expr)
-- a*conjugate(a)*Abs(b)**2 + c*conjugate(c)*Abs(d)**2
instead of the expected
Abs(a)**2*Abs(b)**2 + Abs(c)**2*Abs(d)**2
It does what I want if I apply it two times, though.
On Friday, June 6, 2014 9:49:22 PM UTC+2, Andrei Berceanu wrote:
Well yes, but that doesn´t change the fact that in Mathematica I can just
do
expr /.{x_*Conj[x_] - Abs[x]^2}
and it just works!
On Friday, June 6, 2014 8:59:56 PM UTC+2, Christophe Bal wrote:
A easy to use treeview will be a great tool. No ?
2014-06-06 19:52 GMT+02:00 F. B. franz@gmail.com:
I think that SymPy needs a better term rewriting system. And also a
better pattern matcher.
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[sympy] modify latex representation of user-defined function
I define a function gamma with the following code:
from sympy import *
x = Symbol('x')
class gamma(Function): pass
Its latex representation is
print latex(gamma(x))
\Gamma\left(x\right)
whereas I would like it to be
\gamma\left(x\right)
i.e. lowercase instead of capital.
How can I achieve this?
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[sympy] How can I call sympy by javascript with django / jquery or ajax
Hallo everybody, I'm sorry for this question, but I'm not realy familar with Python. Normally I'm working with PHP and JavaScript, but for my recent project I have to integrate some symbolic math to a webpage. In an Internet search, I came across Sympy. And sympy looks quite good. My problem looks like this: The user should enter a formula in a field. The value of the imput field has to be the formula that should be evaluated. The value of the field should be posted to sympy. (Am I right, that this will work with django oder a simple jquery call? Can anybody give me an example, how to do so?) Sympy has to evaluate the posted formula. The return value should be posted back to JavaScript. Can anyone please tell me how I can implement this. Thanks a lot! Peter -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/fc323b5b-937c-4646-be5a-877601d31dae%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[sympy] Re: modify latex representation of user-defined function
On Friday, 6 June 2014 23:13:39 UTC+2, Andrei Berceanu wrote:
I define a function gamma with the following code:
from sympy import *
x = Symbol('x')
class gamma(Function): pass
Its latex representation is
print latex(gamma(x))
\Gamma\left(x\right)
whereas I would like it to be
\gamma\left(x\right)
i.e. lowercase instead of capital.
How can I achieve this?
This should do it:
class gamma(Function):
def _latex(self, printer):
return r'\gamma{\left(%s \right)}' % printer._print(self.args[0])
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[sympy] Re: How can I call sympy by javascript with django / jquery or ajax
On Friday, 6 June 2014 23:18:19 UTC+2, Peter wrote: Hallo everybody, I'm sorry for this question, but I'm not realy familar with Python. Normally I'm working with PHP and JavaScript, but for my recent project I have to integrate some symbolic math to a webpage. In an Internet search, I came across Sympy. And sympy looks quite good. My problem looks like this: The user should enter a formula in a field. The value of the imput field has to be the formula that should be evaluated. The value of the field should be posted to sympy. (Am I right, that this will work with django oder a simple jquery call? Can anybody give me an example, how to do so?) Sympy has to evaluate the posted formula. The return value should be posted back to JavaScript. Can anyone please tell me how I can implement this. Thanks a lot! Peter You should look into sympy gamma. If you just want a small hack in your django codebase I would look at: http://docs.sympy.org/dev/modules/parsing.html and then maybe return the results as latex and use mathjax to render it nicely on the client side. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/e7d85f48-f576-4777-97d7-2e8b7fc538a4%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Writing Documentation for GA module
I am doing all check out of documentation locally. The pdf file (also rst and html) is on my computer. Note that I just upgraded my computer. Before (Amd Phenom II, 6 cores) the Mathjax took 15 seconds to render. On 06/06/2014 07:21 PM, Aaron Meurer wrote: Did that include time downloading the pdf from the internet? Aaron Meurer On Fri, Jun 6, 2014 at 6:13 PM, Alan Bromborsky abro...@verizon.net wrote: Locally on my computer (i7, 6 cores, 3.2 GHz) it took 8 seconds for the mathjax to render. The pdf file (928 kB) took less than a second to load and display. I also agree that the png display looks really bad. On 06/06/2014 06:43 PM, Aaron Meurer wrote: The png math looks terrible on high resolution displays, so I am -1 for that reason. It's also less accessible (e.g., screen readers cannot do anything with it). I don't think 15 seconds is that bad. You will wait longer than that for a PDF to download. Aaron Meurer On Wed, Jun 4, 2014 at 8:49 AM, Alan Bromborsky abro...@verizon.net wrote: On 06/03/2014 11:40 AM, Ondřej Čertík wrote: On Tue, Jun 3, 2014 at 6:16 AM, Alan Bromborsky abro...@verizon.net wrote: I am currently rewriting the documentation for the GA module and because of the equations (more that even before) it has gotten ridiculous in python-sphinx due to the speed of mathjax (it takes about 15 seconds to render the documentation in Firefox ever time I open it) and the limitations of using latex macros in sphinx with mathjax rendering. Indeed, I don't use mathjax for my notes in Sphinx precisely for the reason you mentioned. However, it is possible to use the latex png output, then it works great. Maybe we can switch to it with SymPy. Would the following solution be acceptable - Drastically simplify the sphinx documentation (basically limit it to the user interface for GA) and include all the explanatory math background with derivations and examples in a pdf document(s) (latex generated) linked to the sphinx documentation. If we don't switch to the png printer in Sphinx, then I think this is the only solution. Question - I know I can link pdf documents to the sphinx documents and I know I can further link other pdf documents to the primary pdf document if I open the primary pdf document in a pdf viewer like evince or acroread. However, if the primary pdf document is opened in the Firefox pdf viewer (as would be done if the document is opened from the sphinx documentation) I cannot link to further pdf documents. Does anyone understand this problem and know of an solution to it? I think it's because Firefox is using its own pdf viewer, so perhaps it doesn't support it. Aaron, is there any argument against switching to the png based math? That fixes all these problems. Ondrej More about link python-sphinx to pdf: The following works (in the rst file) - :download:`GA ../LaTeX_docs/GA.pdf` to open GA.pdf at the beginning. The following does not work - :download:`GA ../LaTeX_docs/GA.pdf#page=12` to open GA.pdf at page 12. However if I use - :download:`GA ../LaTeX_docs/GA.pdf` in the rst file and then change - _downloads/GA.pdf in the html file to - _downloads/GA.pdf#page=12 then the link does open on page 12. Do you know of anyway to code this directly in the rst file? -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/538F23FE.6020307%40verizon.net. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/53924B23.9060405%40verizon.net. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/53924DE1.3050208%40verizon.net. For more options, visit https://groups.google.com/d/optout.
[sympy] Re: How can I call sympy by javascript with django / jquery or ajax
Hi Björn, In the meantime, I tried to install SympyGamma and the Google app engine, as it is described in the manual. Unfortunately I don't know now how I can check if everything works fine, because some steps were discribed for a localhost and not on a remote server. Until today, I've never done a django query, could you please give an example, that I'm able to orient me at that example. Many thanks for your help! Peter Am Freitag, 6. Juni 2014 23:56:01 UTC+2 schrieb Björn Dahlgren: On Friday, 6 June 2014 23:18:19 UTC+2, Peter wrote: Hallo everybody, I'm sorry for this question, but I'm not realy familar with Python. Normally I'm working with PHP and JavaScript, but for my recent project I have to integrate some symbolic math to a webpage. In an Internet search, I came across Sympy. And sympy looks quite good. My problem looks like this: The user should enter a formula in a field. The value of the imput field has to be the formula that should be evaluated. The value of the field should be posted to sympy. (Am I right, that this will work with django oder a simple jquery call? Can anybody give me an example, how to do so?) Sympy has to evaluate the posted formula. The return value should be posted back to JavaScript. Can anyone please tell me how I can implement this. Thanks a lot! Peter You should look into sympy gamma. If you just want a small hack in your django codebase I would look at: http://docs.sympy.org/dev/modules/parsing.html and then maybe return the results as latex and use mathjax to render it nicely on the client side. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/38b6a055-ea01-4d44-88a5-aaad1c586711%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] Re: How can I call sympy by javascript with django / jquery or ajax
You might want to look at http://krum.rz.uni-mannheim.de/jas/ (Java Algebra System (JAS) Project) On 06/06/2014 08:16 PM, Peter wrote: Hi Björn, In the meantime, ItriedtoinstallSympyGammaandtheGoogleappengine,asitisdescribedinthemanual. UnfortunatelyIdon'tknownowhowIcancheckifeverythingworks fine,becausesomestepswere discribed foralocalhostandnotonaremote server. Untiltoday, I'veneverdoneadjangoquery,couldyoupleasegiveanexample,that I'm able to orient me at that example. Manythanksforyourhelp! Peter Am Freitag, 6. Juni 2014 23:56:01 UTC+2 schrieb Björn Dahlgren: On Friday, 6 June 2014 23:18:19 UTC+2, Peter wrote: Hallo everybody, I'm sorry for this question, but I'm not realy familar with Python. Normally I'm working with PHP and JavaScript, but for my recent project I have to integrate some symbolic math to a webpage. In an Internet search, I came across Sympy. And sympy looks quite good. My problem looks like this: The user should enter a formula in a field. The value of the imput field has to be the formula that should be evaluated. The value of the field should be posted to sympy. (Am I right, that this will work with django oder a simple jquery call? Can anybody give me an example, how to do so?) Sympy has to evaluate the posted formula. The return value should be posted back to JavaScript. Can anyone please tell me how I can implement this. Thanks a lot! Peter You should look into sympy gamma. If you just want a small hack in your django codebase I would look at: http://docs.sympy.org/dev/modules/parsing.html http://docs.sympy.org/dev/modules/parsing.html and then maybe return the results as latex and use mathjax to render it nicely on the client side. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com mailto:sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com mailto:sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/38b6a055-ea01-4d44-88a5-aaad1c586711%40googlegroups.com https://groups.google.com/d/msgid/sympy/38b6a055-ea01-4d44-88a5-aaad1c586711%40googlegroups.com?utm_medium=emailutm_source=footer. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/53925D1A.4090803%40verizon.net. For more options, visit https://groups.google.com/d/optout.
Re: [sympy] PRolog Equation Solving System
These are all issues that Harsh should be addressing in his GSoC project. Aaron Meurer On Wed, Jun 4, 2014 at 6:56 AM, F. B. franz.bona...@gmail.com wrote: I had a look at SymPy, it looks like this: In [1]: solve(cos(3*x), x) Out[1]: ⎡π π⎤ ⎢─, ─⎥ ⎣6 2⎦ In [2]: solve(cos(n*x), x) Out[2]: ⎡ π 3⋅π⎤ ⎢───, ───⎥ ⎣2⋅n 2⋅n⎦ It looks like the cos( ) solver just thinks that cos( ) can be zero at two points (pi/2 and 3*pi/2), then calls a solver to match its argument to those values. cos(3*x) == 0 misses thus 5*pi/2, which divided by 3 would give 5*pi/6, the missing solution. By the way, why did the solver implicitly assume that n != 0 ? If n == 0, there are no solutions to cos(n*x) == 0. Is there any representation for periodic infinite sets in SymPy? On Tuesday, June 3, 2014 6:03:26 PM UTC+2, Aaron Meurer wrote: It's getting stuck in the checking routine. Try check=False. If you do rewrite(exp), you get some solutions. Aaron Meurer On Mon, Jun 2, 2014 at 11:33 PM, Rathmann rathm...@gmail.com wrote: Interestingly, the problem that Richard Fateman uses to introduce his critique of Press (and other systems) doesn't look to be a happy one for Sympy. from sympy.abc import x from sympy import cos, solve solve(cos(x)+cos(3*x)+cos(5*x), x) At least in my (not quite up to date) tree, this gives a hang/infinite loop If you do the high-school level cleverness by hand, and replace it with solve(cos(3*x)*(1+2*cos(2*x)), x) [pi/6, pi/3, pi/2, 2*pi/3] which is better, although missing a root at 5pi/6 On Monday, June 2, 2014 8:42:13 AM UTC-7, Aaron Meurer wrote: Ah, but the concept is sound, I think. One just needs to be more careful in the implementation. Given that this program was designed to solve high school algebra, it's not surprising that the author chose to ignore complex variables, for better or for worse. Aaron Meurer On Mon, Jun 2, 2014 at 6:15 AM, Richard Fateman fat...@gmail.com wrote: On Wednesday, May 28, 2014 9:16:46 PM UTC-7, Aaron Meurer wrote: How does it return invalid results? Does it not check if spurious solutions were introduced through multiplying both sides of an equation? yes. Also, if one is inclined to say that computer programs know things, then computer programs presumably are ignorant of things. In which case I think one would say that this program is ignorant of complex variables. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+un...@googlegroups.com. To post to this group, send email to sy...@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/ebdacb2f-d41b-44cf-ba1d-9259ef825e1d%40googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+un...@googlegroups.com. To post to this group, send email to sy...@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/325f15d8-200a-4022-b21f-8286879941d1%40googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/fc862b0e-800c-4e5e-a2dd-a3f4151a61fa%40googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAKgW%3D6%2Bb8gz8gPrQ1-Kes1J-n5-r0GjJAkW78C-aGzn-YVNcdA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
[sympy] How can I call sympy by javascript with django / jquery or ajax
Peter! I dont understand what is it exactly that you want to do but still I would like to help. On 7 Jun 2014 06:00, Alan Bromborsky abro...@verizon.net javascript:_e(%7B%7D,'cvml','abro...@verizon.net'); wrote: In the meantime, I tried to install SympyGamma and the Google app engine, as it is described in the manual. Unfortunately I don't know now how I can check if everything works fine, because some steps were discribed for a localhost and not on a remote server. I guess you can ssh into your remote server and then just follow the steps to install and while running server just add --host=0.0.0.0 to it to make it available to other systems also BUT that will be a bad practice if this project of your is big because that will still be running in dev mode. I think the better solution of it is to upload it on the Google App Engine which also provides you many other options and is free for certain limit which is enough for a small project. Until today, I've never done a django query, could you please give an example, that I'm able to orient me at that example. Just look at the code of SymPyGamma. If i an getting you correctly this is all you need. In one sentence SympyGamma is awesome. -- You received this message because you are subscribed to the Google Groups sympy group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CA%2BOR%3Dbg6xL%2BDPxh0p0EU8aAhQ%2BjZtVxhsTLT_-xbpAoZgEgS-A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
[sympy] Re: Convert from a system of linear equations to a matrix
I just answered this on gitter earlier today, but you can just take the
jacobian of the system to get its matrix form. For example:
In [1]: from sympy import *
In [2]: a, b, c, d = symbols('a, b, c, d')
In [3]: x1, x2, x3, x4 = symbols('x1:5')
In [4]: x = Matrix([x1, x2, x3, x4])
In [5]: system = Matrix([a*x1 + b*x2 + c,
...: c*x1 + d*x3 + 2,
...: c*x3 + b*x4 + a])
In [6]: A = system.jacobian(x)
In [7]: B = A*x - system
In [8]: A
Out[8]:
Matrix([
[a, b, 0, 0],
[c, 0, d, 0],
[0, 0, c, b]])
In [9]: B
Out[9]:
Matrix([
[-c],
[-2],
[-a]])
In [10]: assert A*x - B == system
The functionality I'm adding for my GSoC for linearizing a system of
equations will also be able to return these matrices in a convenient form.
But it's not terribly difficult to solve for these arrangements using the
current functionality.
On Thursday, June 5, 2014 4:22:52 PM UTC-5, Andrei Berceanu wrote:
Was this implemented into sympy at any point? It could be the equivalent
of Mathematica's CoefficientArrays function.
On Thursday, November 14, 2013 5:56:22 AM UTC+1, Chris Smith wrote:
I forgot that as_independent, without the as_Add=True flag will treat
Muls differently. The following will be more robust:
def eqs2matrix(eqs, syms, augment=False):
s
[x + 2*y == 4, 2*c + y/2 == 0]
eqs2matrix(s, (x, c))
(Matrix([
[1, 0],
[0, 2]]), Matrix([
[-2*y + 4],
[-y/2]]))
eqs2matrix([2*c*(x+y)-4],(x, y))
(Matrix([[2*c, 2*c]]), Matrix([[4]]))
s = Matrix([si.lhs - si.rhs if isinstance(si, Equality) else si for
si in eqs])
sym = syms
j = s.jacobian(sym)
rhs = -(s - j*Matrix(sym))
rhs.simplify()
if augment:
j.col_insert(0, rhs)
else:
j = (j, rhs)
return j
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