Re: moments optimization

[Jason Stover]

Looks okay to me.

On Mon, Feb 05, 2007 at 01:33:48PM -0800, Ben Pfaff wrote:
> When I looked at src/math/moments.c earlier, it seemed like we
> were doing more multiplications than necessary.  I'd like to
> check in the following change.  It passes "make check".  Any
> comments?
> 
> --- moments.c.~1.4.~  2007-02-05 13:19:12.000000000 -0800
> +++ moments.c 2007-02-05 13:25:17.000000000 -0800
> @@ -166,23 +166,24 @@ moments_pass_two (struct moments *m, dou
>      {
>        m->w2 += weight;
>  
> -      d = d_power = value - m->mean;
> -      m->d1 += d_power * weight;
> +      d = value - m->mean;
> +      d_power = d * weight;
> +      m->d1 += d_power;
>  
>        if (m->max_moment >= MOMENT_VARIANCE) 
>          {
>            d_power *= d;
> -          m->d2 += d_power * weight;
> +          m->d2 += d_power;
>  
>            if (m->max_moment >= MOMENT_SKEWNESS)
>              {
>                d_power *= d;
> -              m->d3 += d_power * weight;
> +              m->d3 += d_power;
>  
>                if (m->max_moment >= MOMENT_KURTOSIS)
>                  {
>                    d_power *= d;
> -                  m->d4 += d_power * weight;
> +                  m->d4 += d_power;
>                  }
>              }
>          }
> 
> 
> -- 
> Ben Pfaff 
> address@hidden
> http://benpfaff.org
> 
> 
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