How do you linearise sin & cos?
Given power series representations, wouldn't you have to go quadratic or higher?
.... unless you chopped up the domain to smaller intervals then linearly approximated within each them ( from some pre-calculated mid-points say ). You'd have to use more & smaller intervals to retain accuracy when in the extremes ( high rate of change of slope ie. 2nd derivative ). Or some other method - a ( huge ) lookup table for instance?

Sounds like you need something akin to a 'register' command but one which forces, rather than just requests/advises, the compiler to keep it's fingers off.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

How do you linearise sin & cos?
Given power series representations, wouldn't you have to go quadratic or higher?
.... unless you chopped up the domain to smaller intervals then linearly approximated within each them ( from some pre-calculated mid-points say ). You'd have to use more & smaller intervals to retain accuracy when in the extremes ( high rate of change of slope ie. 2nd derivative ). Or some other method - a ( huge ) lookup table for instance?

This is what we do. The nice thing about the linear approximation is that we can perform the float -> int conversion (argument to table index) with just bit-operations in integer registers, which is pretty fast.

Quote:

Sounds like you need something akin to a 'register' command but one which forces, rather than just requests/advises, the compiler to keep it's fingers off.

Precisely. Or, even better, something that assigns priorities to the "register" hints.

## How do you linearise sin &

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How do you linearise sin & cos?

Given power series representations, wouldn't you have to go quadratic or higher?

.... unless you chopped up the domain to smaller intervals then linearly approximated within each them ( from some pre-calculated mid-points say ). You'd have to use more & smaller intervals to retain accuracy when in the extremes ( high rate of change of slope ie. 2nd derivative ). Or some other method - a ( huge ) lookup table for instance?

Sounds like you need something akin to a 'register' command but one which forces, rather than just requests/advises, the compiler to keep it's fingers off.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

## RE: How do you linearise

)

This is what we do. The nice thing about the linear approximation is that we can perform the float -> int conversion (argument to table index) with just bit-operations in integer registers, which is pretty fast.

Precisely. Or, even better, something that assigns priorities to the "register" hints.

BM

BM

## You have made a huge amount

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You have made a huge amount of progress in the way you deal with these code issues. Compliments.

## 4.25 is available. The usual

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4.25 is available. The usual suspects will probably want to dig through the assembler code ...

BM

BM

## RE: 4.25 is available. The

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:-) Yup, will probably try to disassemle it tomorrow and try to find out why it doesn't seem to be faster.

## RE: :-) Yup, will probably

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Thank you! :)

## Even on a weekend,, Bernd was

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Even on a weekend,, Bernd was faster :-). See comments in the thread on the new app.