Intel® oneAPI Math Kernel Library
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FFT Trigonometric transform - zeroes f(0)=0 and f(n)=0

mu_k_
Beginner
126 Views

Hi,
I have a small question about FFT trigonometric in MKL. I have a array of data I wish to transform. But I can't use exponential FFT, I need to use the sine trigonometric transformation. The algorithm wants from the that the array of data begins with zero and ends with zero.
f(0)=0
f(n)=0

But my natural data are not of such kind. Can I do this? : My array A length is m. I will create an array F which has length n=m+2 and I will copy the array A into F. I will define F(0)=0, F(1:m)=A and F(n)=0
Will it work? Will be the transformation right?
And then after the transformation, the transformed F, what should I do? Now I would like to have the values in A but the lenght of A is smaller than F. Can I copy A=F(1:m) and the points F(0) and F(n) not use? Will the array A than the sine FFT of A at the beginning?
I hope so but I'm not sure if I'm not mistaken.
Many thanks

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2 Replies
Alexander_K_Intel2
126 Views

Hi,

Your suggestion is correct. If you want to have sine transform of vector without zero elements on the beginning and on the end you can copy it in temporary array with zero boundaries elements, make a TT transform and after copy it back.

With best regards,

Alexander Kalinkin

mu_k_
Beginner
126 Views

ok, many many thanks!

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