dirbax Posted February 28, 2009 Posted February 28, 2009 Hi , I am working on some math stuff and I need to check some points , so are theses formulas correct ? ISZ(x) : is it 0 ? isz (x) = cos ( pi * ( (2*ceil( abs(x) ) + 1)) / 2 ) / cos(1) Ins : Real number x Out : 1 if x=0 , 0 if x <> 0 --------------------------------------------------------------- SGN(x) : Sign sgn(x) = abs(x) / ( x + isz(x) ) Ins : Real number x Out : 1 if x>0 , 0 if x = 0 , -1 if x < 0 more here Dirbax thanks
dirbax Posted February 28, 2009 Author Posted February 28, 2009 I am trying to create a new math branch DIMD
the tree Posted February 28, 2009 Posted February 28, 2009 But things like the sign function and the dirac delta function... already exist.
dirbax Posted February 28, 2009 Author Posted February 28, 2009 Yes but I still should mention them since I am making the basis of DIMD, an other point is trying to avoid semantic presentation of functions such as this and go for smooth calculations
the tree Posted February 28, 2009 Posted February 28, 2009 For one abs() isn't smooth, at all, neither is ceiling(). And why don't you want the way a function is presented to be semantic? It's not like you're saving on computability, trig functions are clearly more expensive than a check for properties that are written into the way a number is stored.
dirbax Posted March 1, 2009 Author Posted March 1, 2009 For one abs() isn't smooth, at all, neither is ceiling(). True , I am still working on it in order to minimise the number of functions such as ceil and abs which use semantic definition .
the tree Posted March 1, 2009 Posted March 1, 2009 Again, what's wrong with a semantic definition? If makes things possible to read, as well as computationally cheaper, what could possibly be wrong with it? Merged post follows: Consecutive posts mergedAnd it just occurred to me, if you're trying to define discontinuous functions as compositions of continuous ones, it can't be done.
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now