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Log polar error code, Log polar parsing warnings + polar parsing logic when value is zero #302

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Log polar error code, Log polar parsing warnings + polar parsing logic when value is zero #302

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3695134
Log polar error code
sebastien-rosset Jul 5, 2024
0a54f91
Handle scenario when polar contains NaN value
sebastien-rosset Jul 5, 2024
2df2559
Handle scenario when polar contains NaN value
sebastien-rosset Jul 5, 2024
8596f7f
Revert setting speed to 0 when importing polars
sebastien-rosset Jul 7, 2024
770fd60
use isnan function
sebastien-rosset Jul 7, 2024
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19 changes: 16 additions & 3 deletions include/Polar.h
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,17 @@ class Boat;

#define DEGREES 360

// Error codes when Polar::Speed returns NaN.
enum class PolarErrorCode {
None, // No error has occurred.
NegativeWindSpeed, // The input true wind speed is negative.
EmptyPolarData, // The polar file contains no data.
WindAngleOutOfRange, // The input heading is out of the polar range, either too much upwind or too much downwind.
WindSpeedOutOfBounds, // The input wind speed is either below the minimum polar wind or above the maximum polar wind.
NegativeBoatSpeed, // The calculated boat speed is negative.
BoatSpeedNaNValue // The polar data contains NaN boat speed value, which represents unknown speed.
};

class Polar
{
public:
Expand All @@ -63,7 +74,7 @@ class Polar
void OptimizeTackingSpeeds();
void ClosestVWi(double VW, int &VW1i, int &VW2i);

double Speed(double W, double VW, bool bound=false, bool optimize_tacking=false);
double Speed(double W, double VW, bool bound=false, bool optimize_tacking=false, PolarErrorCode* error_code=NULL);
double SpeedAtApparentWindDirection(double A, double VW, double *pW=0);
double SpeedAtApparentWindSpeed(double W, double VA);
double SpeedAtApparentWind(double A, double VA, double *pW=0);
Expand Down Expand Up @@ -102,13 +113,15 @@ class Polar
SailingWindSpeed(double nVW) : VW(nVW) {}

float VW;
std::vector<float> speeds; // by degree_count
std::vector<float> orig_speeds; // by degree_count, from polar file
std::vector<float> speeds; // by degree_count
std::vector<float> orig_speeds; // by degree_count, from polar file.
SailingVMG VMG;
}; // num_wind_speeds
bool VMGAngle(SailingWindSpeed &ws1, SailingWindSpeed &ws2, float VW, float &W);

// The true wind speed for each wind angle in 'degree_steps'.
std::vector<SailingWindSpeed> wind_speeds;
// The values of the true wind angle for which true wind speed is reported.
std::vector<double> degree_steps;
unsigned int degree_step_index[DEGREES];
};
55 changes: 44 additions & 11 deletions src/Polar.cpp
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Expand Up @@ -304,6 +304,7 @@ bool Polar::Open(const wxString &filename, wxString &message)
"To specify interpolated, leave blank values.\n"
"To specify course as 'invalid' use 0.0 rather than 0\n"));
warn_zeros = true;
// Intentionally set s = NAN. This is to indicate the boat speed is unknow.
} else if(*token) {
s = strtod(token, 0);
if(s < .05)
Expand All @@ -326,6 +327,8 @@ bool Polar::Open(const wxString &filename, wxString &message)
UpdateSpeeds();

FileName = wxString::FromUTF8(filename);
if (message != wxEmptyString)
wxLogMessage(message);
return true;

failed:
Expand Down Expand Up @@ -439,7 +442,14 @@ void Polar::OptimizeTackingSpeed()
}
#endif

// return index of wind speed in table which less than our wind speed
/*
* Finds the indices of the two wind speeds in the polar table
* that are just below and above the given true wind speed value.
*
* @param VW The target true wind speed value.
* @param VW1i Output parameter: Index of the wind speed just below the target value.
* @param VW2i Output parameter: Index of the wind speed just above the target value.
*/
void Polar::ClosestVWi(double VW, int &VW1i, int &VW2i)
{
for(unsigned int VWi = 1; VWi < wind_speeds.size()-1; VWi++)
Expand All @@ -449,6 +459,7 @@ void Polar::ClosestVWi(double VW, int &VW1i, int &VW2i)
return;
}

// If the target wind speed is greater than all available wind speeds, set indices to the last wind speed.
VW2i = wind_speeds.size()-1;
VW1i = VW2i > 0 ? VW2i - 1 : 0;
}
Expand Down Expand Up @@ -484,35 +495,50 @@ bool Polar::VMGAngle(SailingWindSpeed &ws1, SailingWindSpeed &ws2, float VW, flo
/**
* Calculate the boat speed (VB) based on the wind angle (W) and wind speed (VW) using the polar data.
*
* @param W The wind angle in degrees.
* @param VW The wind speed in knots.
* @param W The true wind angle in degrees.
* @param VW The true wind speed in knots.
* @param bound If true, the wind speed must be within the bounds of the polar data.
* For example, if the wind speed is 25 knots and the polar data only goes up to 20 knots,
* the function will return NAN.
* If false, the wind speed is extrapolated if outside the bounds.
* @param optimize_tacking Flag indicating whether to optimize for tacking angles.
* @return The boat speed (VB) in knots.
* @param[out] error_code The error code if NaN is returned.
* @return The boat speed (VB) in knots, or NaN in the following scenarios:
* - If the wind speed (VW) is negative.
* - If the polar data is empty (no degree steps or wind speeds defined).
* - If optimize_tacking is false and the wind angle (W) is outside the range of the polar data.
* - If bound is true and the wind speed (VW) is outside the range of the polar data.
* - If the calculated boat speed is negative (which can happen with faulty polars or during extrapolation).
*/
double Polar::Speed(double W, double VW, bool bound, bool optimize_tacking)
double Polar::Speed(double W, double VW, bool bound, bool optimize_tacking, PolarErrorCode* error_code)
{
if(VW < 0)
if (error_code) *error_code = PolarErrorCode::None;
if(VW < 0) {
if (error_code) *error_code = PolarErrorCode::NegativeWindSpeed;
return NAN;
}

if(!degree_steps.size() || !wind_speeds.size())
if(!degree_steps.size() || !wind_speeds.size()) {
if (error_code) *error_code = PolarErrorCode::EmptyPolarData;
return NAN;
}

W = positive_degrees(W);

// assume symmetric
if(W > 180)
W = 360 - W;

if(!optimize_tacking && (W < degree_steps[0] || W > degree_steps[degree_steps.size()-1]))
if(!optimize_tacking && (W < degree_steps[0] || W > degree_steps[degree_steps.size()-1])) {
// Avoid upwind course (polar angle too low) or downwind no-go zone (polar angle too high).
if (error_code) *error_code = PolarErrorCode::WindAngleOutOfRange;
return NAN;
}

if(bound && (VW < wind_speeds[0].VW || VW > wind_speeds[wind_speeds.size()-1].VW))
if(bound && (VW < wind_speeds[0].VW || VW > wind_speeds[wind_speeds.size()-1].VW)) {
if (error_code) *error_code = PolarErrorCode::WindSpeedOutOfBounds;
return NAN;
}

unsigned int W1i = degree_step_index[(int)floor(W)];
unsigned int W2i = W1i +1;
Expand All @@ -529,7 +555,7 @@ double Polar::Speed(double W, double VW, bool bound, bool optimize_tacking)
if(optimize_tacking) {
float vmgW = W;
if(VMGAngle(ws1, ws2, VW, vmgW))
return Speed(vmgW, VW, bound)*cos(deg2rad(vmgW))/cos(deg2rad(W));
return Speed(vmgW, VW, bound, false, error_code)*cos(deg2rad(vmgW))/cos(deg2rad(W));
}

double VW1 = ws1.VW, VW2 = ws2.VW;
Expand All @@ -542,8 +568,15 @@ double Polar::Speed(double W, double VW, bool bound, bool optimize_tacking)

double VB = interp_value(W, W1, W2, VB1, VB2);

if(VB < 0) // with faulty polars, extrapolation, sometimes results in negative boat speed
if(VB < 0) {
// with faulty polars, extrapolation, sometimes results in negative boat speed
if (error_code) *error_code = PolarErrorCode::NegativeBoatSpeed;
return NAN;
} else if (isnan(VB)) {
// This happens if the Polar contains NAN values.
if (error_code) *error_code = PolarErrorCode::BoatSpeedNaNValue;
return NAN;
}

return VB;
}
Expand Down
13 changes: 8 additions & 5 deletions src/RouteMap.cpp
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Expand Up @@ -639,6 +639,7 @@ static inline bool ComputeBoatSpeed
double &B, double &VB, double &BG, double &VBG, double &dist, int newpolar)
{
Polar &polar = configuration.boat.Polars[newpolar];
PolarErrorCode error_code = PolarErrorCode::None;
if((data_mask & Position::CLIMATOLOGY_WIND) &&
(configuration.ClimatologyType == RouteMapConfiguration::CUMULATIVE_MAP ||
configuration.ClimatologyType == RouteMapConfiguration::CUMULATIVE_MINUS_CALMS)) {
Expand All @@ -652,23 +653,25 @@ static inline bool ComputeBoatSpeed
double VBc, mind = polar.MinDegreeStep();
// if tacking
if(fabs(dir) < mind)
VBc = polar.Speed(mind, atlas.VW[i], true, configuration.OptimizeTacking)
VBc = polar.Speed(mind, atlas.VW[i], true, configuration.OptimizeTacking, &error_code)
* cos(deg2rad(mind)) / cos(deg2rad(dir));
else
VBc = polar.Speed(dir, atlas.VW[i], true, configuration.OptimizeTacking);
VBc = polar.Speed(dir, atlas.VW[i], true, configuration.OptimizeTacking, &error_code);

VB += atlas.directions[i]*VBc;
}

if(configuration.ClimatologyType == RouteMapConfiguration::CUMULATIVE_MINUS_CALMS)
VB *= 1-atlas.calm;
} else
VB = polar.Speed(H, VW, true, configuration.OptimizeTacking);
} else {
VB = polar.Speed(H, VW, true, configuration.OptimizeTacking, &error_code);
}

/* failed to determine speed.. */
if(std::isnan(B) || std::isnan(VB)) {
// when does this hit??
printf("polar failed bad! %f %f %f %f\n", W, VW, B, VB);
wxLogWarning("polar failed. V: %f VW: %f B: %f VB: %f H: %f. Error: %d",
W, VW, B, VB, H, error_code);
configuration.polar_failed = true;
return false; //B = VB = 0;
}
Expand Down