Fix error with if condition.

Author: niccolotubini

src/main/java/it/geoframe/blogspot/closureequation/closureequation/SWRCBrooksCorey.java

@@ -35,7 +35,7 @@ public class SWRCBrooksCorey extends SoilWaterRetentionCurve {
 	@Override
 	public double f(double x, double y, int id) {
 
-		if(x>0.0) {
+		if(x>=0.0) {
 			return super.parameters.thetaS[id] +
 					9.81*(super.parameters.alphaSpecificStorage[id] + super.parameters.thetaS[id]*super.parameters.betaSpecificStorage[id])*x;
 		} else if(x<=super.parameters.par2[id]) {
@@ -50,7 +50,7 @@ public double f(double x, double y, int id) {
 	@Override
 	public double df(double x, double y, int id) {
 
-		if(x>0.0) {
+		if(x>=0.0) {
 			return 9.81*( super.parameters.alphaSpecificStorage[id] + super.parameters.thetaS[id]*super.parameters.betaSpecificStorage[id] );
 		} else if(x<=super.parameters.par2[id]) {
 			return super.parameters.par1[id]*(super.parameters.thetaS[id] - super.parameters.thetaR[id])/Math.abs(super.parameters.par2[id]) * Math.pow(super.parameters.par2[id]/x,super.parameters.par1[id]+1);

src/main/java/it/geoframe/blogspot/closureequation/closureequation/SWRCKosugi.java

@@ -38,7 +38,7 @@ public class SWRCKosugi extends SoilWaterRetentionCurve {
 	public double f(double x, double y, int id) {
 
 
-		if(x>0.0) {
+		if(x>=0.0) {
 			return super.parameters.thetaS[id] +
 					9.81*(super.parameters.alphaSpecificStorage[id] + super.parameters.thetaS[id]*super.parameters.betaSpecificStorage[id])*x;
 		} else {
@@ -53,7 +53,7 @@ public double f(double x, double y, int id) {
 	@Override
 	public double df(double x, double y, int id) {
 
-		if(x>0.0) {
+		if(x>=0.0) {
 			return 9.81*( super.parameters.alphaSpecificStorage[id] + super.parameters.thetaS[id]*super.parameters.betaSpecificStorage[id] );
 		} else {
 			return (super.parameters.thetaS[id]-super.parameters.thetaR[id])/(Math.sqrt(2*Math.PI)*super.parameters.par2[id]*(-x)) * Math.exp(-Math.pow( Math.log(x/super.parameters.par1[id]),2)/(2*Math.pow(super.parameters.par2[id],2)));

src/main/java/it/geoframe/blogspot/closureequation/closureequation/SWRCVanGenuchten.java

@@ -39,7 +39,7 @@ public double f(double x, double y, int id) {
 
 		m = 1-1/super.parameters.par1[id];
 
-		if(x>0.0) {
+		if(x>=0.0) {
 			return super.parameters.thetaS[id] +
 					9.81*(super.parameters.alphaSpecificStorage[id] + super.parameters.thetaS[id]*super.parameters.betaSpecificStorage[id])*x;
 		} else {
@@ -55,7 +55,7 @@ public double f(double x, double y, int id) {
 	public double df(double x, double y, int id) {
 		m = 1-1/super.parameters.par1[id];
 
-		if(x>0.0) {
+		if(x>=0.0) {
 			return 9.81*( super.parameters.alphaSpecificStorage[id] + super.parameters.thetaS[id]*super.parameters.betaSpecificStorage[id] );
 		} else {
 			return super.parameters.par2[id]*super.parameters.par1[id]*this.m*(super.parameters.thetaS[id] - super.parameters.thetaR[id]) / Math.pow(1.0 + Math.pow(Math.abs(super.parameters.par2[id]*x), super.parameters.par1[id]), this.m + 1.0)*Math.pow(Math.abs(super.parameters.par2[id]*x), super.parameters.par1[id] - 1.0);