How does one "solve" an inequality?

hum, maybe 'solve' is not the right word, sorry... for now, using lsolve(), I can make GiNaC answer "x == -y" for equality "x+y == 0" (looking at 'x'). My question is : if I'm looking for 'x', in the inequality " x+y < 0", how can GiNaC give me "x < -y" ? cheers Fred 2010/3/19 Harish Narayanan <harish.mlists@gmail.com>:

On 3/19/10 12:31 AM, Frederic wrote:

...

Hi,

I'm new here, I only test GiNaC to see how it can help me. What I've seen of it so far with is very nice, especially C++ objects (no need to parse strings).

But I don't see how to solve inequalities : x+y < 0

lsolve tells me : terminate called after throwing an instance of 'std::invalid_argument'   what():  lsolve(): 1st argument must be a list of equations

it works just fine with real equalities (replaced the '<' by '==' ): x+y == 0

I use GiNaC 1.5.2 on a 64b ubuntu system. But I haven't seen anything related on newer version's changelog.

can GiNaC solve inequalities ? If yes, how ?!? and if no, why ? is it planned ?

thanks in advance for any input...

How does one "solve" an inequality?

Harish