I'm going to write a modified version of MakeGraph by mike3

[JmsNxn]

Hey, Gottfried!

That's not the speed up!!!!!!!!!!!!

(...)
Say that func(z) takes 1 second to evaluate. Then to run mike3's program, we need at least 1000x1000 seconds to graph. Where my speed up is 500x500 seconds.

Think of it as a lossy compression algorithm!!!!!

Hi James -

I see;
well I had made some suggestion before, and became critical of that yesterday, noticing finally, that the speedup expected does not occur, just a much smaller effect. So my suggestions came out to have little effect only. (But *that fact* is/was noticeable I think)

Just to check/see this detail - that has been the intention of my second post.    

- - - -

Of course: an interpolation-method whose reducing power goes into a quadratic formula (like yours) overpowers any optimization which has a linear reduction of time, no question.

Thanks gottfried!

The main point is that you can't even tell the difference; despite the fact we have used a quasi lossy compression formula. The eye cannot tell. But it goes way faster. And it's still accurate... enough!

When you're evaluating 2x2 pixels once instead of 1x1 pixels 4 times, and "splining" with a linear formula, they eye can't tell   And it's still accurate enough.

The only trouble is when tetration goes from a trillion trillion to zero in a flash. In that case, my speed up looks pixelated. But I can live with that, if I can make bigger graphs which are basically identical when everything is reasonable .