Feature Request: Symlet16

[M-Colley]

Hey there, thank you for your nice package!

I was wondering whether you could also implement the symlet16 version?

That would be really helpful for me.

Kind regards

[graetz23]

Hi there,

many thanks, you are welcome.

Sure, do you have the coefficients or a function / formula to great those?

best
Chris

[M-Colley]

This is the most challenging part - I have failed to find that. Where did you find the coefficients for the previous ones?

Maybe I can renew my search from there.

Kind regards

[M-Colley]

I did find these: https://www.continuummechanics.org/wavedaubcoefs.html

However, I am not sure whether they are adequate.

[M-Colley]

Maybe these are actually correct?

https://github.com/PyWavelets/pywt/blob/cf622996f3f0dedde214ab696afcd024660826dc/pywt/_extensions/c/wavelets_coeffs.template.h#L1677

static const TYPE CAT(sym16_, TYPE)[32] = {
-1.0797982104319795e-005, -5.3964831793152419e-006, 0.00016545679579108483, 3.656592483348223e-005, -0.0013387206066921965, -0.00022211647621176323, 0.0069377611308027096, 0.001359844742484172, -0.024952758046290123, -0.0035102750683740089, 0.078037852903419913, 0.03072113906330156, -0.15959219218520598, -0.054040601387606135, 0.47534280601152273, 0.75652498787569711, 0.39712293362064416, -0.034574228416972504, -0.066983049070217779, 0.032333091610663785, 0.0048692744049046071, -0.031051202843553064, -0.0031265171722710075, 0.012666731659857348, 0.00071821197883178923, -0.0038809122526038786, -0.0001084456223089688, 0.00085235471080470952, 2.8078582128442894e-005, -0.00010943147929529757, -3.1135564076219692e-006, 6.2300067012207606e-006
};

If so, it might be great to add the additional symlets that are currently missing as well?

Kind regards

[graetz23]

Hi,

sorry for the delay, the holidays are busy :-)

I can give those a try, let me check, hope it's ok by some days?

best
Christian

[M-Colley]

Hi, no worries at all - I am very grateful for that - happy holidays :)

Kind regards
Mark

[graetz23]

@M-Colley I have added it by copying your supported coefficients from pywavelets ..

I quickly make an executable project in a sub folder and have that in an extra branch for teting the precision. However, you can give it already a try :-)

Merry Christmas
Christian

[graetz23]

Hi Mark,

the rounding error is smaller than: 1e-14, so the Symlet16 works fine by the methods of Main.

Let me know if it works for you too.

best & a merry Christmas
Christian