1 files changed, 41 insertions, 24 deletions

diff --git a/src/Scilab2C/SCI2CTests/test999_WorkingDir/scilabcode/mainfunction.sci b/src/Scilab2C/SCI2CTests/test999_WorkingDir/scilabcode/mainfunction.sci
index bfb5fc3f..75829d99 100644
--- a/src/Scilab2C/SCI2CTests/test999_WorkingDir/scilabcode/mainfunction.sci
+++ b/src/Scilab2C/SCI2CTests/test999_WorkingDir/scilabcode/mainfunction.sci
@@ -1,29 +1,46 @@
-//SCI2C: DEFAULT_PRECISION= DOUBLE
+//SCI2C: DEFAULT_PRECISION= DOUBLE

 
-function mainfunction()
+function mainfunction()

 
-// ------------------------------
-// --- Simple Scalar Addition ---
-// ------------------------------
-a = 1;
-b = 2;
-c = 0;
-c = a + b;
-disp(c);
+// Knowing that 
+// (1) P * (V^gamma) = C
+// Where
+// P = Pressure
+// V = Volume
+// gamma,C = constants depending on the particular gas used.
+// (2) log10(P) = log10(C) - gamma*log10(V)
+// (3) x = log10(V) 
+// (4) y = log10(P)
+// than (2) becomes:
+// y = a + b*x;
+// Where
+// a = log10(C)
+// b = -gamma
+// Then thanks to this transformation it is possible to perform 
+// a linear regression to estimate gamma and C!
 
-// ------------------------------
-// --- Trigonometric Identity ---
-// ------------------------------
-x = (1:3)' * (4:9);
-y = (sin(x).^2) + (cos(x).^2);
-disp(x);
-disp(y-ones(3,6));
+Volume   = [54.3 61.8 72.4 88.7 118.6 194.0];
+Pressure = [61.2 49.5 37.6 28.4 19.2 10.1];
+x = log10(Volume);
+y = log10(Pressure);
 
-// -------------------------------
-// --- Computation of Distance ---
-// -------------------------------
-// generate a vector w
-w = cos(sin(cos(x*3)*2).* x+ones(3,6).*cos(x-sin(y*2)));
-distxw = sqrt(x.^2 + w.^2);
-disp(distxw);
+a = (sum(y)*sum(x.^2)-sum(x)*sum(x.*y))./(length(x)*sum(x.^2)-sum(x).*sum(x));
+b = (length(x)*sum(x.*y)-sum(x)*sum(y))./(length(x)*sum(x.^2)-sum(x).*sum(x));
+
+// Other way to compute a and b
+beq = sum((x-mean(x)).*(y-mean(y)))./sum((x-mean(x)).^2);

+aeq = mean(y)-mean(x)*beq;

+
+C = 10 .^a;
+gamma = -b;
+disp('C')
+disp(C)
+disp('gamma');
+disp(gamma);
+disp('a-aeq');
+disp(a-aeq)
+disp('b-beq')
+disp(b-beq)
+// plot(Volume,Pressure);
+// plot(Volume,(C ./(Volume.^gamma)),'r')
 endfunction