public static unsafe double[] Iir(double[] src, double[] coeff, int initCount)
{
int order = coeff.Length / 2 - 1;
if (src.Length < 5)
{
throw new Exception("Invalid IIR src length");
}
if (order < 1)
{
throw new Exception("Invalid IIR coeff length");
}
double[] dst = new double[src.Length];
double[] delLine = new double[order];
IppStatus st = 0;
//Get buffer size for filter
int sz = 0;
st = Ipps.ippsIIRGetStateSize_64f(order, ref sz);
if (st != IppStatus.ippStsNoErr)
{
throw new Exception(string.Format("IIRGetStateSize error {0}", st));
}
//Buffer for IIR state information.
//This is used between calls to ipp and so must be fixed
byte[] buf = new byte[sz];
fixed(byte *pbuf = &buf[0])
{
IntPtr pstate = IntPtr.Zero;
st = Ipps.ippsIIRInit_64f(ref pstate, coeff, order, delLine, pbuf);
if (st != IppStatus.ippStsNoErr)
{
throw new Exception(string.Format("IIRInit error {0}", st));
}
//Initialize the filter to minimize settling
for (int i = 0; i < initCount; ++i)
{
st = Ipps.ippsIIR_64f(src, dst, 1, pstate);
if (st != IppStatus.ippStsNoErr)
{
throw new Exception(string.Format("IIR error {0}", st));
}
}
//Filter all the data
st = Ipps.ippsIIR_64f(src, dst, src.Length, pstate);
if (st != IppStatus.ippStsNoErr)
{
throw new Exception(string.Format("IIR error {0}", st));
}
}
return(dst);
}
public static unsafe double[] Fir(double[] src, double[] taps, bool shift)
{
double[] dst = new double[src.Length];
double[] delLine = new double[taps.Length];
IppStatus st = 0;
if (src.Length < 5)
{
throw new Exception("Invalid FIR src length");
}
if (taps.Length < 1)
{
throw new Exception("Invalid FIR win length");
}
//Initialize delay line from initial sample and sample gradient
double dd = src[1] - src[0];
delLine[0] = src[0] - dd;
for (int i = 1; i < delLine.Length; ++i)
{
delLine[i] = delLine[i - 1] - dd;
}
//Get buffer size for filter
int sz = 0;
st = Ipps.ippsFIRGetStateSize_64f(taps.Length, ref sz);
if (st != IppStatus.ippStsNoErr)
{
throw new Exception(string.Format("FIRGetStateSize error {0}", st));
}
//Buffer for FIR state information.
//This is used between calls to ipp and so must be fixed
byte[] buf = new byte[sz];
fixed(byte *pbuf = &buf[0])
{
IntPtr pstate = IntPtr.Zero;
//pstate is initialized to point to somewhere in pbuf
st = Ipps.ippsFIRInit_64f(ref pstate, taps, taps.Length, delLine, pbuf);
if (st != IppStatus.ippStsNoErr)
{
throw new Exception(string.Format("FIRInit error {0}", st));
}
st = Ipps.ippsFIR_64f(src, dst, src.Length, pstate);
if (st != IppStatus.ippStsNoErr)
{
throw new Exception(string.Format("FIR error {0}", st));
}
if (shift)
{
//Move the samples forward in the dst vector by half the filter length
//to compensate for filter phase delay and pad at final sample value and gradient
int w2 = taps.Length / 2;
Array.Copy(dst, w2, dst, 0, dst.Length - w2);
dd = src[src.Length - 1] - src[src.Length - 2];
double g = src[src.Length - 1] + dd;
double d = 0;
for (int i = dst.Length - w2; i < dst.Length; ++i)
{
st = Ipps.ippsFIROne_64f(g, ref d, pstate);
if (st != IppStatus.ippStsNoErr)
{
throw new Exception(string.Format("FIROne error {0}", st));
}
dst[i] = d;
g += dd;
}
}
}
return(dst);
}
