search for: rhapson

Hi, I have been using R for close to two years now and have grown quite comfortable with the language. I am presently trying to implement an optimization routine in R (Newton Rhapson). I have some R functions that calculate the gradient and hessian (pre requisite matrices) fairly efficiently. Now, I have to call this function iteratively until some convergance criterion is reached. I think the standard method of doing this in most programming languages is a while loop. However,...

...one - B*y0*y0); /* Now that we have a good estimate of 1/sqrt(x) we need to invert it. We will also approximate this. */ B = y1; #ifdef __GNUC__ asm("fres %0,%1" : "=f" (y0) : "f" (B)); #else y0 = __fres(B); #endif /* Do a Newton-Rhapson refinement step on the reciprocal estimate */ y1 = y0 + y0*(1.0 - B*y0); return y1; } #else static inline double _fast_sqrt(double x) { return sqrt(x); } #endif -tim --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubsc...

Looking through the archives I have seen talk of making CPU specific optimisations for Vorbis, a la MMX/3DNow!/SSE. The feeling I gather is to wait until something is working well in C before committing to any kind of specific optimisation. What if oft used and needed DSP functions were identified and standardised DSP functionality be written for Vorbis? This would seperate the basically