String [] SF = loadStrings("F.val");       // reads array of strings from a file named F.val in the sketch folder
int n=SF.length;                           // sets the number of values in the array
float [] F = new float [n];                // table of values that will be extracted from the strings
for (int i=0; i<n; i++) F[i]=float(SF[i]); // store string forms of F values

for (int i=0; i<n; i++) println(F[i]);     // prints read values in the bottom pane

int r = 2*n-1;                             // number of values in refined array 
float [] R = new float [r];                // refined array 
for (int i=0; i<n; i++) R[2*i]=F[i];       // copies F values into even entries of R
for (int i=3; i<r-3; i=i+2) R[i]=((-R[i-3]+9*R[i-1]+9*R[i+1]-R[i+3])/16);  // computes intermediate odd values through cubit interpolation
R[1]=(3*R[0]+6*R[2]-R[4])/8;                // computes first and last odd value through quadratic interplation
R[r-2]=(3*R[r-1]+6*R[r-3]-R[r-5])/8;

println(); for (int i=0; i<r; i++) println(R[i]);     // prints new values in the bottom pane

String [] SR = new String [r];            // allocate table of strings that will contain strings representing R[0], R[1]...R[r-1]
for (int i=0; i<r; i++) SR[i]=str(R[i]);  // store string forms of R values in SR
saveStrings("F.val",SR);                  // writes content of SR to a file named F.val in the sketch folder (overwrites)