Re: [VOLK] a += b*c ?

[Johannes Demel]

Hi Randall,

in your case,

https://github.com/gnuradio/volk/blob/main/kernels/volk/volk_32f_x2_multiply_32f.h

followed by
https://github.com/gnuradio/volk/blob/main/kernels/volk/volk_32f_x2_add_32f.h

would be the way to go at the moment.
```
volk_32f_x2_multiply_32f(multiply_result, b, c, num_samples);
volk_32f_x2_add_32f(a, a, multiply_result, num_samples);
```

You're welcome to start a new kernel
```
volk_32f_x3_multiply_add_32f(out, a, b, c, num_samples);
```
In fact, it would be a great addition to VOLK.

Cheers
Johannes


On 16.08.22 01:38, Randall Wayth wrote:
> Thanks for the suggestions and apologies for not being 100% clear at the 
> start.
> I'm not looking for a dot product. I'm looking for
> a[i] += b[i]*c[i]     specifically for floating point
>
> So it would be the equivalent of IPP's ippsAddProduct_32f.
> The application is to apply a window to a set of samples before 
> accumulating, to implement a weighted overlap add PFB. In my case the 
> samples are real-valued, but I could also see a case for a and b being 
> complex, or the case for b being 8 or 16-bit ints with a and c being 
> floating point.
>
> Cheers,
> Randall

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