SParameters.h

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* libscopehal v0.1                                                                                                     *
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#ifndef SParameters_h
#define SParameters_h
 
#include <complex>
 
class SParameterPoint
{
public:
    SParameterPoint()
    {}
 
    SParameterPoint(float f, float a, float p)
    : m_frequency(f)
    , m_amplitude(a)
    , m_phase(p)
    {
    }
 
    SParameterPoint(float f, std::complex<float> c)
    : m_frequency(f)
    , m_amplitude(abs(c))
    , m_phase(arg(c))
    {
    }
 
    float   m_frequency;    //Hz
    float   m_amplitude;    //magnitude
    float   m_phase;        //radians from -pi to +pi
 
    std::complex<float> ToComplex()
    { return std::polar(m_amplitude, m_phase); }
};
 
class SParameterVector
{
public:
    SParameterVector()
    {}
 
    SParameterVector(const WaveformBase* wmag, const WaveformBase* wang)
    {
        auto umag = dynamic_cast<const UniformAnalogWaveform*>(wmag);
        auto smag = dynamic_cast<const SparseAnalogWaveform*>(wmag);
 
        auto uang = dynamic_cast<const UniformAnalogWaveform*>(wang);
        auto sang = dynamic_cast<const SparseAnalogWaveform*>(wang);
 
        if(umag && uang)
            ConvertFromWaveforms(umag, uang);
        else
            ConvertFromWaveforms(smag, sang);
    }
 
    SParameterVector(const SparseAnalogWaveform* wmag, const SparseAnalogWaveform* wang)
    {
        ConvertFromWaveforms(wmag, wang);
    }
 
    SParameterVector(const UniformAnalogWaveform* wmag, const UniformAnalogWaveform* wang)
    {
        ConvertFromWaveforms(wmag, wang);
    }
 
    template<class T>
    __attribute__((noinline))
    void ConvertFromWaveforms(const T* wmag, const T* wang)
    {
        if( (wmag == nullptr) || (wang == nullptr) )
        {
            LogError("Null input supplied to SParameterVector::ConvertFromWaveforms\n");
            return;
        }
 
        size_t len = std::min(wmag->size(), wang->size());
        m_points.resize(len);
        m_points.PrepareForCpuAccess();
 
        float ascale = M_PI / 180;
        for(size_t i=0; i<len; i++)
        {
            m_points[i] = SParameterPoint(
                GetOffsetScaled(wmag, i),
                pow(10, wmag->m_samples[i] / 20),
                wang->m_samples[i] * ascale);
        }
 
        m_points.MarkModifiedFromCpu();
    }
 
    template<class T>
    __attribute__((noinline))
    void ZeroFromWaveforms(const T* wmag, const T* wang)
    {
        if( (wmag == nullptr) || (wang == nullptr) )
        {
            LogError("Null input supplied to SParameterVector::ZeroFromWaveforms\n");
            return;
        }
 
        size_t len = std::min(wmag->size(), wang->size());
        m_points.resize(len);
        m_points.PrepareForCpuAccess();
 
        for(size_t i=0; i<len; i++)
            m_points[i] = SParameterPoint(GetOffsetScaled(wmag, i), 0, 0);
 
        m_points.MarkModifiedFromCpu();
    }
 
    void ConvertToWaveforms(SparseAnalogWaveform* wmag, SparseAnalogWaveform* wang);
 
    SParameterPoint InterpolatePoint(float frequency) const;
    float InterpolateMagnitude(float frequency) const;
    float InterpolateAngle(float frequency) const;
 
    AcceleratorBuffer<SParameterPoint> m_points;
 
    void resize(size_t nsize)
    { m_points.resize(nsize); }
 
    float GetGroupDelay(size_t bin) const;
 
    size_t size() const
    { return m_points.size(); }
 
    SParameterPoint& operator[](size_t i)
    { return m_points[i]; }
 
    void clear()
    { m_points.clear(); }
 
protected:
    float InterpolatePhase(float phase_lo, float phase_hi, float frac) const;
};
 
typedef std::pair<int, int> SPair;
 
class SParameters
{
public:
    SParameters();
    virtual ~SParameters();
 
    void Clear();
    void Allocate(int nports = 2);
 
    bool empty() const
    { return m_params.empty(); }
 
    SParameterPoint SamplePoint(int to, int from, float frequency)
    { return m_params[ SPair(to, from) ]->InterpolatePoint(frequency); }
 
    SParameterVector& operator[] (SPair pair)
    { return *m_params[pair]; }
 
    const SParameterVector& operator[] (SPair pair) const
    { return *(m_params.find(pair)->second); }
 
    friend class TouchstoneParser;
 
    enum FreqUnit
    {
        FREQ_HZ,
        FREQ_KHZ,
        FREQ_MHZ,
        FREQ_GHZ
    };
 
    enum ParameterFormat
    {
        FORMAT_MAG_ANGLE,
        FORMAT_DBMAG_ANGLE,
        FORMAT_REAL_IMAGINARY
    };
 
    void SaveToFile(const std::string& path, ParameterFormat format = FORMAT_MAG_ANGLE, FreqUnit freqUnit = FREQ_GHZ);
 
    size_t GetNumPorts() const
    { return m_nports; }
 
protected:
    std::map< SPair , SParameterVector*> m_params;
 
    size_t m_nports;
};
 
#endif