fun cosft1(y: DoubleArray?) { com.nr.fft.FFT.cosft1(y) }
Calculates the cosine transform of a set y [ 0..n ] of real-valued data points . The transformed data replace the original data in array y. n must be a power of 2 . This program , without changes , also calculates the inverse cosine transform , but in this case the output array should be multiplied by 2/n .