Changed serial printf to more portable snprintf and serial print, changed int to double so can use floats in datapoints

Author: Rowan Easter

library.properties

@@ -1,10 +1,10 @@
 name=CurveFitting
-version=1.0.2
+version=1.0.3
 author=Rotario <[email protected]>
 maintainer=Rotario <[email protected]>
 sentence=Fits polynomial curves to given datapoints
 paragraph=Fit polynomial curves to given points using least squares regression. The max order of polynomial fitting is 20, this should be more than enough to fit most practical problems. All values are kept as double for precision, this works well on a Teensy due to its floating point unit and large (64 bit) double precision. the numbers required increase exponentially as the number of points or order increases.
 url=https://github.com/Rotario/arduinoCurveFitting
 includes=curveFitting.h
-category=Data Processing, Sensors
+category=Data Processing
 architectures=*

src/curveFitting.cpp

@@ -11,19 +11,23 @@
 
 void printMat(const char *s, double*m, int n){
   Serial.println(s);
+  char buf[40];
   for (int i = 0; i < n; i++) {
     for (int j = 0; j < n; j++) {
-      Serial.printf("%30.2f\t", m[i*n+j]);
+      snprintf(buf, 40, "%30.4f\t", m[i*n+j]);
+      Serial.print(buf);
     }
     Serial.println();
   }
 }
 
 void showmat(const char *s, double **m, int n){
   Serial.println(s);
+  char buf[40];
   for (int i = 0; i < n; i++) {
     for (int j = 0; j < n; j++){
-      Serial.printf("%30.2f\t", m[i][j]);
+      snprintf(buf, 40, "%30.4f\t", m[i][j]);
+      Serial.print(buf);
     }
     Serial.println();
   }
@@ -101,14 +105,14 @@ double curveFitPower(double base, int exponent){
 
 int fitCurve (int order, int nPoints, double py[], int nCoeffs, double *coeffs) {
   uint8_t maxOrder = MAX_ORDER;
-  if (nCoeffs != order + 1) return ORDER_AND_NCOEFFS_DOES_NOT_MATCH; 	// no of coefficients is one larger than the order of the equation
+  if (nCoeffs != order + 1) return ORDER_AND_NCOEFFS_DO_NOT_MATCH; 	// no of coefficients is one larger than the order of the equation
   if (nCoeffs > maxOrder || nCoeffs < 2) return ORDER_INCORRECT; 		//matrix memory hard coded for max of 20 order, which is huge
   if (nPoints < 1) return NPOINTS_INCORRECT; 							//Npoints needs to be positive and nonzero
   int i, j;
   double T[maxOrder] = {0}; //Values to generate RHS of linear equation
   double S[maxOrder*2+1] = {0}; //Values for LHS and RHS of linear equation
   double denom; //denominator for Cramer's rule, determinant of LHS linear equation
-  int x, y;
+  double x, y;
 
   double px[nPoints]; //Generate X values, from 0 to n
   for (i=0; i<nPoints; i++){
@@ -135,28 +139,28 @@ int fitCurve (int order, int nPoints, double py[], int nCoeffs, double *coeffs)
 
   double mat[nCoeffs*nCoeffs]; //Temp matrix as det() method alters the matrix given
   cpyArray(masterMat, mat, nCoeffs);
-  denom = det(mat, nCoeffs, 0);
+  denom = det(mat, nCoeffs, CURVE_FIT_DEBUG);
   cpyArray(masterMat, mat, nCoeffs);
 
   //Generate cramers rule mats
   for (i = 0; i < nCoeffs; i++){ //Temporary matrix to substitute RHS of linear equation as per Cramer's rule
     subCol(mat, T, i, nCoeffs);
-    coeffs[nCoeffs-i-1] = det(mat, nCoeffs, 0)/denom; //Coefficients are det(M_i)/det(Master)
+    coeffs[nCoeffs-i-1] = det(mat, nCoeffs, CURVE_FIT_DEBUG)/denom; //Coefficients are det(M_i)/det(Master)
     cpyArray(masterMat, mat, nCoeffs);
   }
   return 0;
 }
 
 int fitCurve (int order, int nPoints, double px[], double py[], int nCoeffs, double *coeffs) {
   uint8_t maxOrder = MAX_ORDER;
-  if (nCoeffs != order + 1) return ORDER_AND_NCOEFFS_DOES_NOT_MATCH; 	//Number of coefficients is one larger than the order of the equation
+  if (nCoeffs != order + 1) return ORDER_AND_NCOEFFS_DO_NOT_MATCH; 	//Number of coefficients is one larger than the order of the equation
   if(nCoeffs > maxOrder || nCoeffs < 2) return ORDER_INCORRECT; 		//Matrix memory hard coded for max of 20 order, which is huge
   if (nPoints < 1) return NPOINTS_INCORRECT; 							//Npoints needs to be positive and nonzero
   int i, j;
   double T[maxOrder] = {0}; //Values to generate RHS of linear equation
   double S[maxOrder*2+1] = {0}; //Values for LHS and RHS of linear equation
   double denom; //denominator for Cramer's rule, determinant of LHS linear equation
-  int x, y;
+  double x, y;
 
   for (i=0; i<nPoints; i++) {//Generate matrix elements
     x = px[i];
@@ -178,14 +182,14 @@ int fitCurve (int order, int nPoints, double px[], double py[], int nCoeffs, dou
 
   double mat[nCoeffs*nCoeffs]; //Temp matrix as det() method alters the matrix given
   cpyArray(masterMat, mat, nCoeffs);
-  denom = det(mat, nCoeffs, 0);
+  denom = det(mat, nCoeffs, CURVE_FIT_DEBUG);
   cpyArray(masterMat, mat, nCoeffs);
 
   //Generate cramers rule mats
   for (i = 0; i < nCoeffs; i++){ //Temporary matrix to substitute RHS of linear equation as per Cramer's rule
     subCol(mat, T, i, nCoeffs);
-    coeffs[nCoeffs-i-1] = det(mat, nCoeffs, 0)/denom; //Coefficients are det(M_i)/det(Master)
+    coeffs[nCoeffs-i-1] = det(mat, nCoeffs, CURVE_FIT_DEBUG)/denom; //Coefficients are det(M_i)/det(Master)
     cpyArray(masterMat, mat, nCoeffs);
   }
   return 0;
-}
+}

src/curveFitting.h

@@ -10,11 +10,15 @@
 #define curveFit_h
 
 #include <Arduino.h>
-#define MAX_ORDER 20;
+#define MAX_ORDER 20
+
+#ifndef CURVE_FIT_DEBUG
+#define CURVE_FIT_DEBUG 0
+#endif
 
 /* Enum for error messages */
 enum curveFitERROR{
-	ORDER_AND_NCOEFFS_DOES_NOT_MATCH = -1,
+	ORDER_AND_NCOEFFS_DO_NOT_MATCH = -1,
 	ORDER_INCORRECT = -2,
 	NPOINTS_INCORRECT = -3
 };