Create secant.m

Author: ergineeer

secant.m

@@ -0,0 +1,32 @@
+function [rootVal,EaFinal,i,elapsedTime] = secant(f,x1,x2,stoppingErrorCriteria,maxIterations)
+    tic
+    xVect = zeros(maxIterations,1);
+    Ea = xVect;
+    xVect(1,1) = x1;
+    xVect(2,1) = x2;
+    
+    for i=2:maxIterations
+        xVect(i+1,1) = xVect(i,1)-(f(xVect(i,1))*(xVect(i-1,1)-xVect(i,1))/( f(xVect(i-1,1))-f(xVect(i,1))));
+        Ea(i,1) = 100*abs((xVect(i,1)-xVect(i-1,1))/xVect(i,1));
+        ifNaN = any(xVect(i+1,1));
+        if ifNaN == 0
+            xVectFinal(1:i,1) = xVect(1:i,1);
+            EaVectFinal(1:i+1,1) = Ea(1:i+1,1);
+            break
+        end
+        if i>1 && Ea(i,1)<stoppingErrorCriteria
+            xVectFinal(1:i,1) = xVect(1:i,1);
+            EaVectFinal(1:i+1,1) = Ea(1:i+1,1);
+            break
+        end
+    end
+    rootVal = xVectFinal(end,1);
+    EaFinal = EaVectFinal(end,1); 
+    i = i-1;    
+    plot(-14:0.01:5,f(-14:0.01:5),'k')
+    grid on; hold on
+    plot(xVectFinal(end,1),f(xVectFinal(end,1)),'b*')
+    plot(xVectFinal,f(xVectFinal),'go')
+    xlabel('x'); ylabel('y(x)')
+    elapsedTime = toc;
+end