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2014/10/15 ¤U¤È 10:12:23
iphone Programming Glossary: originalrealUsing the apple FFT and accelerate Framework http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework needs to standardise how to pack real numbers into it. so first we generate n real numbers 1 2 ... n for i 0 i n i originalReal i float i 1 Next we pack them into A as n 2 complex #s 1. masquerades n real #s as n 2 complex #s 2 1i 4 3i ... 2. splits.. #s as n 2 complex #s 2 1i 4 3i ... 2. splits to A.realP 2 4 ... n 2 elts A.compP 1 3 ... n 2 elts vDSP_ctoz COMPLEX originalReal 2 stride 2 as each complex # is 2 floats A 1 stride 1 in A.realP .compP nOver2 n 2 elts You would really need to look..
iPhone FFT with Accelerate framework vDSP http://stackoverflow.com/questions/6358764/iphone-fft-with-accelerate-framework-vdsp version to get 16 byte alignment. A.realp float malloc nOver2 sizeof float A.imagp float malloc nOver2 sizeof float originalReal float malloc n sizeof float obtainedReal float malloc n sizeof float if originalReal NULL A.realp NULL A.imagp NULL printf.. float malloc nOver2 sizeof float originalReal float malloc n sizeof float obtainedReal float malloc n sizeof float if originalReal NULL A.realp NULL A.imagp NULL printf nmalloc failed to allocate memory for the real FFT section of the sample. n exit 0.. memory for the real FFT section of the sample. n exit 0 Generate an input signal in the real domain. for i 0 i n i originalReal i float i 1 Look at the real signal as an interleaved complex vector by casting it. Then call the transformation function..
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