ActivityPredictor/FFTManager.cpp at master · RideReport/ActivityPredictor · GitHub

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// FFTManager.c

// Ride

// Created by William Henderson on 3/7/16.

#include "FFTManager.h"

#include<stdio.h>

#include <Accelerate/Accelerate.h>

struct FFTManager {

FFTSetup fftWeights;

};

FFTManager *createFFTManager(int sampleCount)

{

// assert(fmod(log2(sampleCount), 1.0) == 0.0); // sampleCount must be a power of 2

struct FFTManager *f;

f = (struct FFTManager*) malloc(sizeof(struct FFTManager));

f->fftWeights = vDSP_create_fftsetup(vDSP_Length(log2f(sampleCount)), FFT_RADIX2);

return f;

}

void deleteFFTManager(FFTManager *fftManager)

{

vDSP_destroy_fftsetup(fftManager->fftWeights);

free(fftManager);

}

void fft(FFTManager *manager, float * input, int inputSize, float *output)

{

// apply a hamming window to the input

float *hammingWindow = new float[inputSize];

vDSP_hamm_window(hammingWindow, inputSize, 0);

float *hammedInput = new float[inputSize]();

vDSP_vmul(input, 1, hammingWindow, 1, hammedInput, 1, inputSize);

// pack the input samples in preparation for FFT

float *zeroArray = new float[inputSize]();

DSPSplitComplex splitComplex = {.realp = hammedInput, .imagp = zeroArray};

// run the FFT and get the magnitude components (vDSP_zvmags returns squared components)

vDSP_fft_zip(manager->fftWeights, &splitComplex, 1, log2f(inputSize), FFT_FORWARD);

vDSP_zvmags(&splitComplex, 1, output, 1, inputSize);

delete[](zeroArray);

delete[](hammingWindow);

}

void autocorrelation(float *input, int inputSize, float *output)

{

int lenSignal = 2 * inputSize - 1;

float *signal = new float[lenSignal];

for (int i = 0; i < inputSize; i++) {

if (i < inputSize) {

signal[i] = input[i];

} else {

signal[i] = 0;

}

// float *result = new float[inputSize];

// vDSP_conv(signal, 1, &input[inputSize - 1], -1, result, 1, inputSize, inputSize);

vDSP_conv(signal, 1, &input[inputSize - 1], -1, output, 1, inputSize, inputSize);

delete[](signal);

// free(result);

// return 0.0;

}

float dominantPower(float *input, int inputSize)

{

float dominantPower = 0;

for (int i=1; i<=inputSize/2; i+=1) {

float value = input[i];

if (value > dominantPower) {

dominantPower = value;

}

return dominantPower;

}

ActivityPredictor/FFTManager.cpp at master · RideReport/ActivityPredictor · GitHub

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