Where communities thrive


  • Join over 1.5M+ people
  • Join over 100K+ communities
  • Free without limits
  • Create your own community
People
Repo info
Activity
Richard Otis
@richardotis
Thanks again for your work. Absolute game-changer for our project.
Ondřej Čertík
@certik
@richardotis I am really glad SymEngine is working for you. Are you at the SciPy 2019 conference?
Richard Otis
@richardotis
@certik Not this year, no. There is an annual conference in June I always go to, and hitting a July one as well has always been a tough lift for my employer
I've been trying to convince @bocklund to go and present on his work
I have a March-April conference slot I've been looking to replace with a SciPy-type conference, though.
Ondřej Čertík
@certik
@richardotis no problem I understand. I haven't gone for SciPy in many years until this year I finally made it.
Marcello
@torshind_gitlab
Hello, please have a look at this:
    r1 = add(add(real_double(0.), x), y);
    std::cout << *r1 << std::endl;

    r1 = expand(add(add(real_double(0.), x), y));
    std::cout << *r1 << std::endl;

    r1 = expand(add(x, mul(real_double(4.), y)));
    std::cout << *r1 << std::endl;

    r1 = expand(add(x, mul(real_double(4.), add(y, z))));
    std::cout << *r1 << std::endl;

    r1 = expand(add(x, mul(integer(4), add(y, z))));
    std::cout << *r1 << std::endl;

    r1 = expand(mul(real_double(4.), add(y, z)));
    std::cout << *r1 << std::endl;

    r1 = expand(mul(integer(4), add(y, z)));
    std::cout << *r1 << std::endl;
Output:
x + y
x + y
x + 4.0*y
0.0 + x + 4.0*y + 4.0*z
x + 4*y + 4*z
0.0 + 4.0*y + 4.0*z
4*y + 4*z
Do you have any idea how to eliminate the spurious 0.0 when the coefficients are double?
Isuru Fernando
@isuruf
Its a tough one. We want expand(4.0*(x + y - (x+y))) to give 0.0 instead of 0 to make it clear that the expression is inexact (floating point vs integer)
You can eliminate 0.0 in the final expression by checking if the expression is an Add and if the coefficient is 0.0, remove it
But that doesn't fix 0.0 in intermediate expressions
On second thought, returning 0 for expand(4.0*(x + y - (x+y))) is totally fine
Isuru Fernando
@isuruf
Currently, in symengine 0 * 4.0 gives 0.0, but it should probably return 0. @certik, what do you think?
Isuru Fernando
@isuruf
Marcello
@torshind_gitlab
I deleted my previous message because I verified that the workaround that I've proposed doesn't work. Sorry for the confusion.
Isuru Fernando
@isuruf
@torshind_gitlab, you need to use integer(0) as the coefficient in the code you posted previously
Marcello
@torshind_gitlab
yep, if get_coef()->is_zero() is true, forcing an exact coefficient does the trick
thanks again @isuruf
Isuru Fernando
@isuruf
@richardotis, @bocklund, I've released 0.4.1 of symengine. With conda you can use python-symengine 0.4.0 and symengine 0.4.1
I could use some help in fixing the tests of symengine.py at symengine/symengine.py#289
Steven Lee
@stevenleeS0ht
Is there versioning compatibility requirement between symengine and python-symengine?
Isuru Fernando
@isuruf
@stevenleeS0ht, yes, we usually only support one version of symengine recorded at https://github.com/symengine/symengine.py/blob/master/symengine_version.txt
Carl Poppa
@tgn3000

@isuruf Hi Isuru, long time no see! Was wondering if the following behavior is expected. Thanks!! (master, ed7479baf59a36636061acc35b676bcf9073a932)

int main() {
  RCP<const Basic> a = symbol("a"), b = symbol("b"), c = symbol("c");
  map_basic_basic d {{mul(a,b), c}};
  RCP<const Basic> r1 = mul(SymEngine::integer(2), mul(a, b)),
  r2 = add(SymEngine::integer(1), r1);
  std::cout << *r1 << " -> " << *r1->subs(d) << std::endl;
  std::cout << *r2 << " -> " << *r2->subs(d) << std::endl;
  return 0;
}

produces

2*a*b -> 2*a*b
1 + 2*a*b -> 1 + 2*c
Isuru Fernando
@isuruf
@tgn3000, looks like an oversight
Note that, we have
2*a*b*c -> 2*a*b*c
1 + 2*a*b*c -> 1+2*a*b*c
Richard Otis
@richardotis
Hi @isuruf , do you have a sense what the blockers are for the next release of symengine.py? The new as_ctypes API enables some really nice solver accuracy improvements for us downstream, and also lets pycalphad resolve an install-time bug related to finding libsymengine.
Isuru Fernando
@isuruf
@richardotis, I'd like to get #1596, #1582, #1592 done

The new as_ctypes API enables some really nice solver accuracy improvements for us downstream

What's the difference between this and the cython one?

Richard Otis
@richardotis
Two things: it supports the lambda backend with nogil calling (current release doesn't), and it eliminates symengine as a build-time dependency
Richard Otis
@richardotis
@isuruf Thanks for your hard work getting the new release out there. Our downstream CI picked it up without skipping a beat.
Sylvain Corlay
@SylvainCorlay
:+1:
Jogi Miglani
@jmig5776
Can anybody please guide me on this symengine/symengine#1617?
Ondřej Čertík
@certik
@jmig5776 I just replied there.
Jogi Miglani
@jmig5776
Yaa I am on it.Thanks
Dario Izzo
@darioizzo
Is there a user documentation for symengine? I am struggling to find one ...
Isuru Fernando
@isuruf
@darioizzo, it's at https://symengine.github.io/classSymEngine_1_1Add.html , but it has close to zero documentation
Bjorn
@bjodah
@darioizzo even though it's not a 1:1 mapping, SymPy's documentation is a good place to look since many functions are essentially a reimplementation in C++. Also, I find the tests in SymEngine to be quite approachable for examples of usage.
Jogi Miglani
@jmig5776
Btw can anyone tell me that what's the plan for documentation for symengine, because I myself facing very much problems while implementing cancel for apart ....if there is predefined plan then I would like to help in that
ronald00773
@ronald00773
How to install symengine for python 3 using macports? I tried using sudo port install symengine and I was not able to use in python3
Isuru Fernando
@isuruf
@ronald00773, install pip and then do python3 -m pip install symengine
ronald00773
@ronald00773
thanks @isuruf
Ammar Alam Malik
@ammalik221
Hey, everyone.
This is Ammar and I am new to open source. Can anyone get me started?
sparkkk3l
@sparkkk3l
Hello, everyone .
I am new to opensource ,so i want help on how to get started. I am good in c++,still learning though trying to make my coding skills more better.
can anyone guide me on open source,it will really helpfull to me.
Arpan Chattopadhyay
@Arpan612
Hello, everyone. My name is Arpan. I have been active in the main SymPy room and Github page. Among the proposed projects, I am interested in SymEngine- SymPy integration, could someone please tell me what all is expected in the proposal?
@isuruf Respected Sir, could you please help me out?
Isuru Fernando
@isuruf
@Arpan612, the linked issues give some details