# Should I get the absolute value of the result of the inverse discrete fourier transform？

The result of equation 36 can be positive and negative.And if I don't get the absolute value of it,the ocean surface tend to be very regular.But according to the paper,the author never get the absolute value of the result of the equation 36. http://www-evasion.imag.fr/Membres/Fabrice.Neyret/NaturalScenes/fluids/water/waves/fluids-nuages/waves/Jonathan/articlesCG/simulating-ocean-water-01.pdf

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Could you reformulate your question such that one doesn't have to read to whole paper? – draks ... Nov 29 '12 at 11:53
The main idea of the paper is to simulate the ocean by inverse discrete fourier transform.We already have the spectrum of the ocean.The fourier components preserve the complex conjugation property.So the result of the inverse discrete fourier transform is real value.The question is that if I do not get the absolute of the result of the IDFT(inverse discrete fourier transform),the ocean tend to be very regular.But the paper do not indicate it. – user1859053 Nov 29 '12 at 12:04
What I don't get is why you think that the absolute value should be taken. Is there a problem with the ocean being regular? To answer the question in the title: depends. Do you need the absolute value? If you need to use it for something, of course you should take the absolute value. If you don't, then it is just an extra computation for no good reason... – Willie Wong Nov 30 '12 at 8:46
I have solved this problem.Thank you. – user1859053 Dec 3 '12 at 14:19