[apps/proba] Fix Student and Chi2 parameter name and initialisation

apps/probability/base.de.i18n

@@ -22,5 +22,5 @@ LambdaExponentialDefinition = "λ: Parameter"
 MeanDefinition = "μ: Erwartungswert"
 DeviationDefinition = "σ: Standardabweichung"
 LambdaPoissonDefinition = "λ: Parameter"
-DegreesOfFreedomDefinition = "d : Freiheitsgraden"
+DegreesOfFreedomDefinition = "k: Anzahl der Freiheitsgrade"
 ComputeProbability = "Wahrscheinlichkeit berechnen"

apps/probability/base.en.i18n

@@ -22,5 +22,5 @@ LambdaExponentialDefinition = "λ: Rate parameter"
 MeanDefinition = "μ: Mean"
 DeviationDefinition = "σ: Standard deviation"
 LambdaPoissonDefinition = "λ: Parameter"
-DegreesOfFreedomDefinition = "d : Degrees of freedom"
+DegreesOfFreedomDefinition = "k: Degrees of freedom"
 ComputeProbability = "Calculate probabilities"

apps/probability/base.es.i18n

@@ -22,5 +22,5 @@ LambdaExponentialDefinition = "λ : Parámetro"
 MeanDefinition = "μ : Media"
 DeviationDefinition = "σ : Desviación típica"
 LambdaPoissonDefinition = "λ : Parámetro"
-DegreesOfFreedomDefinition = "d : Grados de libertad"
+DegreesOfFreedomDefinition = "k : Grados de libertad"
 ComputeProbability = "Calcular las probabilidades"

apps/probability/base.fr.i18n

@@ -22,5 +22,5 @@ LambdaExponentialDefinition = "λ : Paramètre"
 MeanDefinition = "μ : Espérance ou moyenne"
 DeviationDefinition = "σ : Écart type"
 LambdaPoissonDefinition = "λ : Paramètre"
-DegreesOfFreedomDefinition = "d : Degrés de liberté"
+DegreesOfFreedomDefinition = "k : Degrés de liberté"
 ComputeProbability = "Calculer les probabilités"

apps/probability/base.pt.i18n

@@ -22,5 +22,5 @@ LambdaExponentialDefinition = "λ : Parâmetro"
 MeanDefinition = "μ : Média"
 DeviationDefinition = "σ : Desvio padrão"
 LambdaPoissonDefinition = "λ : Parâmetro"
-DegreesOfFreedomDefinition = "d : Graus de liberdade"
+DegreesOfFreedomDefinition = "k : Graus de liberdade"
 ComputeProbability = "Calcular probabilidades"

apps/probability/law/chi_squared_law.cpp

@@ -14,12 +14,12 @@ float ChiSquaredLaw::xMax() const {
 }
 
 float ChiSquaredLaw::yMax() const {
-  const float halfD = m_parameter1/2;
+  const float halfk = m_parameter1/2;
   float result;
-  if (halfD <= 1 + FLT_EPSILON) {
+  if (halfk <= 1 + FLT_EPSILON) {
     result = 0.5f;
   } else {
-    result = coefficient() * std::pow(halfD - 1, halfD - 1);
+    result = coefficient() * std::pow(halfk - 1, halfk - 1);
   }
   return result * (1.0f + k_displayTopMarginRatio);
 }
@@ -28,9 +28,9 @@ float ChiSquaredLaw::evaluateAtAbscissa(float x) const {
   if (x < 0) {
     return NAN;
   }
-  const float halfD = m_parameter1/2;
+  const float halfk = m_parameter1/2;
   const float halfX = x/2;
-  return coefficient() * std::pow(halfX, halfD-1) * std::exp(-halfX);
+  return coefficient() * std::pow(halfX, halfk-1) * std::exp(-halfX);
 }
 
 bool ChiSquaredLaw::authorizedValueAtIndex(float x, int index) const {
@@ -57,8 +57,8 @@ double ChiSquaredLaw::cumulativeDistributiveInverseForProbability(double * proba
 }
 
 float ChiSquaredLaw::coefficient() const {
-  const float halfD = m_parameter1/2;
-  return 1 / (2 * std::exp(std::lgamma(halfD)));
+  const float halfk = m_parameter1/2;
+  return 1 / (2 * std::exp(std::lgamma(halfk)));
 }
 
 }

apps/probability/law/chi_squared_law.h

@@ -7,7 +7,7 @@ namespace Probability {
 
 class ChiSquaredLaw : public OneParameterLaw {
 public:
-  ChiSquaredLaw() : OneParameterLaw(4.0f) {}
+  ChiSquaredLaw() : OneParameterLaw(1.0f) {}
   I18n::Message title() override { return I18n::Message::ChiSquaredLaw; }
   Type type() const override { return Type::ChiSquared; }
   bool isContinuous() const override { return true; }
@@ -16,7 +16,7 @@ public:
   float yMax() const override;
   I18n::Message parameterNameAtIndex(int index) override {
     assert(index == 0);
-    return I18n::Message::D;
+    return I18n::Message::K;
   }
   I18n::Message parameterDefinitionAtIndex(int index) override {
     assert(index == 0);

apps/probability/law/student_law.cpp

@@ -42,8 +42,8 @@ double StudentLaw::cumulativeDistributiveInverseForProbability(double * probabil
 }
 
 float StudentLaw::coefficient() const {
-  const float d = m_parameter1;
-  const float lnOfResult = std::lgamma((d+1)/2) - std::lgamma(d/2) - (M_PI+d)/2;
+  const float k = m_parameter1;
+  const float lnOfResult = std::lgamma((k+1)/2) - std::lgamma(k/2) - (M_PI+k)/2;
   return std::exp(lnOfResult);
 }
 

apps/probability/law/student_law.h

@@ -7,7 +7,7 @@ namespace Probability {
 
 class StudentLaw : public OneParameterLaw {
 public:
-  StudentLaw() : OneParameterLaw(4.0f) {}
+  StudentLaw() : OneParameterLaw(1.0f) {}
   I18n::Message title() override { return I18n::Message::StudentLaw; }
   Type type() const override { return Type::Student; }
   bool isContinuous() const override { return true; }
@@ -16,7 +16,7 @@ public:
   float yMax() const override;
   I18n::Message parameterNameAtIndex(int index) override {
     assert(index == 0);
-    return I18n::Message::D;
+    return I18n::Message::K;
   }
   I18n::Message parameterDefinitionAtIndex(int index) override {
     assert(index == 0);

apps/shared.universal.i18n

@@ -34,6 +34,7 @@ IntCommand = "int(\x11,x,\x11,\x11)"
 IntCommandWithArg = "int(f(x),x,a,b)"
 InverseCommandWithArg = "inverse(M)"
 InvSortCommandWithArg = "sort>(L)"
+K = "k"
 Lambda = "λ"
 LcmCommandWithArg = "lcm(p,q)"
 LinearRegressionFormula  = " y=a·x+b "