Am 06.08.2010 um 17:53 schrieb Alexei Sheplyakov:
Hi,
On Fri, Aug 06, 2010 at 01:26:29PM +0200, Kraus Philipp wrote:
That's nice, but not my thinking, because the expressions are std::string data, that can be set by a user, so I can't use your example.
Correct. But you don't need to parse "(t - formula)^2/2", instead you can construct the expression directly:
I can't construct it directly, because the error function can be changed, so in my template class it must be a little bit dynamic.
The Problem is, that my formula a*x^3 + b*y^4 (*) not correct substitute into the other formula:
What makes you think so? As far as I understand (t - a*x^3 - b*y^4)^2 is the same as (a*x^3 + b*y^4 - t)^2
I'm now a little bit confused, cause I'm working for a long time with this problem and I don't see my "thinking error". If I have an expression eg exp(x), so (t-exp(x))^2 is not the same (exp(x)-t)^2. Sorry I don't see it Thanks Phil