I have noticed unexpected behavior when trying to take the absolute
value of a complex exponential (e^{i\theta}). For example, the following
command fails with "unable to simplify to float approximation":
plot(abs(exp(i*pi*x)),x,0,3)
However, the following gives the correct plot (of constant val
Dear Jaap,
I have made an ETS-3.5.0-20101024.p0.spkg (I've just modified the spkg-install,
and every setup.cfg and setup.py for each one of the functions according to the
ones you have in the ETS-3.2 spkg), everything compiles OK, but at the end I
get this message:
===
On 10/25/10 11:32 AM, andrew ewart wrote:
f = z*x^3+x*y^3+y*z^3;
H = f.diff(2)
If you can just treat f as a symbolic polynomial, you can use the
symbolic expressions to compute the hessian. Here are several ways to
do this:
sage: f(x,y,z) = z*x^3+x*y^3+y*z^3 # note this makes x,y,z sym
Hi all,
I recently tried to install sage in ubuntu 10.10 (no problems), and
then I tried to install the latest version of SnapPy.
Following the instructions, at the setup.py install step,
i get the following error when trying to build the snappy.CyOpenGL
extension:
building 'snappy.CyOpenGL' ex
Andrew,
Read up on resultants:
sage: R.=QQ[]
sage: f=x^2+a1*x+a2
sage: g=x^2+b1*x+b2
sage: f(x=y).resultant(g(x=x-y),variable=y)
a1^2*b1*x + a1*b1^2*x + a1^2*x^2 + 3*a1*b1*x^2 + b1^2*x^2 + 2*a1*x^3 +
2*b1*x^3 + x^4 + a1*a2*b1 + a2*b1^2 + a1^2*b2 + a1*b1*b2 + 2*a1*a2*x +
2*a2*b1*x + 2*a1*b2*x + 2*
I made a modification so it can take 1, 3, 4, ... number of operands
nicely.
def symround(x, ndigits=0):
if hasattr(x,'operator') and x.operator():
o = map( lambda y : symround(y,ndigits=ndigits) , x.operands() )
r = o[0]
for i in xrange(1,x.nops()):
r = x.operator(
I want to translate the following code from magma to SAGE
KK := CyclotomicField(21);
ze := ep^3;
RR := PolynomialRing(KK,3);
PP := Proj(RR);
F := z*x^3+x*y^3+y*z^3;
H := 1/2*Determinant(1/3*Matrix(3,3,
[Derivative(Derivative(F,RR.i),RR.j) : i in [1..3], j in [1..3]]));
Flex := Points(Scheme(PP,[F,
Hi Burcin,
On 25 Okt., 15:26, Burcin Erocal wrote:
> This initializes a list with a single element for objects which return
> None for operator() now. IMHO, this approach is inefficient. In this
> case, you should act on the object directly.
I didnt claim that it was efficient - my code was inte
Hi Simon,
On Mon, 25 Oct 2010 06:09:16 -0700 (PDT)
Simon King wrote:
> On 25 Okt., 14:39, Burcin Erocal wrote:
> > If we return an identity operator for these cases, how do you plan
> > to test for it in your code:
>
> Something like this:
>
> L = x.operands()
> if len(L)>1:
> return x.op
PS:
I know that testing "is None" is faster than "len(L)>1" and wouldn't
insist that there *has* to be an identity operator. One has to
consider two different cases anyway.
However, if there *is* an operator, s==s.operator()(*s.operands())
should hold.
Cheers,
Simon
--
To post to this group, s
Hi Burcin!
On 25 Okt., 14:39, Burcin Erocal wrote:
> If we return an identity operator for these cases, how do you plan to
> test for it in your code:
Something like this:
L = x.operands()
if len(L)>1:
return x.operator()(*map(lambda ..., L))
else:
try:
return x.operator()(round
Hi Simon,
On Mon, 25 Oct 2010 05:09:06 -0700 (PDT)
Simon King wrote:
> I only opened one ticket, namely #10169, aiming at making
> s==s.operator()(*s.operands()) work uniformely.
I don't think this makes sense for variables, numeric objects, or
constants, in other words, objects for which .ope
Hi Burcin,
On 25 Okt., 11:04, Burcin Erocal wrote:
> I suggest we raise a ValueError when there is no operator or operands.
> This is already done for iterators of symbolic expressions in #7537:
>
> http://trac.sagemath.org/sage_trac/ticket/7537
>
> Can you open a ticket to do the same for operan
Hi Simon,
On Mon, 25 Oct 2010 00:41:07 -0700 (PDT)
Simon King wrote:
> @symbolic experts (Burcin et al):
> Is it really necessary that x.operator() returns None and x.operands()
> returns []? What about an identity operator?
The operator and operands don't have a meaning if you have a single
va
Hi Cristóvão!
On 25 Okt., 03:30, Cristóvão Sousa wrote:
> ...
> It just has a minor bug when the operator has more than two operands,
> like x+y+z, but I'll try to fix it as I got the picture now.
Yes, to my surprise, the "add" operator only accepts two arguments,
but the list of operands of a s
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