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?
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
thanks again @isuruf
I could use some help in fixing the tests of symengine.py at symengine/symengine.py#289
@stevenleeS0ht, yes, we usually only support one version of symengine recorded at https://github.com/symengine/symengine.py/blob/master/symengine_version.txt
@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
Note that, we have
2*a*b*c -> 2*a*b*c
1 + 2*a*b*c -> 1+2*a*b*c
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?
@darioizzo, it's at https://symengine.github.io/classSymEngine_1_1Add.html , but it has close to zero documentation
@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.