/// <summary>
/// Contains DFTKey
/// </summary>
/// <param name="fftSampleCount">fft运算的点数</param>
/// <param name="type">fft类型</param>
/// <returns></returns>
private bool Contains(uint fftSampleCount, DFTType type)
{
var k = new DFTKey()
{
FFTSampleCount = fftSampleCount,
Type = type
};
ulong keyId = k.GetKeyNum();
return(_dftDescDict.ContainsKey(keyId));
}
/// <summary>
/// Get DFTKey
/// </summary>
/// <param name="fftSampleCount">fft运算的点数</param>
/// <param name="type">fft类型</param>
/// <returns></returns>
public IntPtr GetDFTDesc(int fftSampleCount, DFTType type)
{
var k = new DFTKey()
{
FFTSampleCount = (uint)fftSampleCount,
Type = type
};
var keyId = k.GetKeyNum();
lock (_dftDescDict)
{
//存在该Key则直接返回
if (_dftDescDict.ContainsKey(keyId))
{
return(_dftDescDict[keyId]);
}
var desc = IntPtr.Zero;
int precision, forwardDomain, dimension, length = fftSampleCount, ret;
//不存在，则创建并配置，保存后返回
#region ------------根据不同变换类型创建描述符，并分别配置（如果有）-------------
switch (type)
{
case DFTType.Double1DRealInComplexOut:
precision = DFTI.DOUBLE;
forwardDomain = DFTI.REAL;
dimension = 1;
if (0 != (ret = DFTI.DftiCreateDescriptor(ref desc, precision, forwardDomain,
dimension, length)))
{
throw new JYDSPInnerException("DftiCreateDescriptor Failed, error code = " + ret);
}
if (0 != (ret = DFTI.DftiSetValue(desc, DFTI.PACKED_FORMAT, DFTI.CCS_FORMAT)))
{
throw new JYDSPInnerException("DftiSetValue PACKED_FORMAT Failed, error code = " + ret);
}
break;
case DFTType.Double1DComplexInComplexOut:
precision = DFTI.DOUBLE;
forwardDomain = DFTI.COMPLEX;
dimension = 1;
if (0 != (ret = DFTI.DftiCreateDescriptor(ref desc, precision, forwardDomain,
dimension, length)))
{
throw new JYDSPInnerException("DftiCreateDescriptor Failed, error code = " + ret);
}
break;
case DFTType.Single1DRealInComplexOut:
precision = DFTI.SINGLE;
forwardDomain = DFTI.REAL;
dimension = 1;
if (0 != (ret = DFTI.DftiCreateDescriptor(ref desc, precision, forwardDomain,
dimension, length)))
{
throw new JYDSPInnerException("DftiCreateDescriptor Failed, error code = " + ret);
}
if (0 != (ret = DFTI.DftiSetValue(desc, DFTI.PACKED_FORMAT, DFTI.CCS_FORMAT)))
{
throw new JYDSPInnerException("DftiSetValue PACKED_FORMAT Failed, error code = " + ret);
}
break;
case DFTType.Single1DComplexInComplexOut:
precision = DFTI.SINGLE;
forwardDomain = DFTI.COMPLEX;
dimension = 1;
if (0 != (ret = DFTI.DftiCreateDescriptor(ref desc, precision, forwardDomain,
dimension, length)))
{
throw new JYDSPInnerException("DftiCreateDescriptor Failed, error code = " + ret);
}
break;
default:
throw new ArgumentOutOfRangeException(nameof(type), type, null);
}
#endregion
#region ------------------公共设置------------------
var scaleFactor = 1.0 / length;
//配置IFFT的ScaleFactor
if (0 != (ret = DFTI.DftiSetValue(desc, DFTI.BACKWARD_SCALE, scaleFactor)))
{
throw new JYDSPInnerException("DftiSetValue Failed, error code = " + ret);
}
//配置DFTI_PLACEMENT为DFTI_NOT_INPLACE,即FFT后的结果不覆盖原输入信号
if (0 != (ret = DFTI.DftiSetValue(desc, DFTI.PLACEMENT, DFTI.NOT_INPLACE)))
{
throw new JYDSPInnerException("DftiSetValue PLACEMENT Failed, error code = " + ret);
}
if (0 != (ret = DFTI.DftiCommitDescriptor(desc)))
{
throw new JYDSPInnerException("DftiCommitDescriptor Failed, error code = " + ret);
}
#endregion
//保存描述符并返回
_dftDescDict.Add(keyId, desc);
return(desc);
}
}