--- /dev/null
+package net.sf.openrocket.util;
+
+import java.lang.reflect.Array;
+
+public class ArrayUtils {
+
+ /**
+ * Returns a double array with values from start to end with given step.
+ * Starts exactly at start and stops at the multiple of step <= stop.
+ */
+ public static double[] range(double start, double stop, double step){
+
+ int size = (int) Math.floor(((stop - start) / step)) + 1;
+
+ //System.out.println("Range from "+start+" to "+stop+" step "+step+" has length "+size);
+
+ double[] output = new double[size];
+ int i = 0;
+ double x = start;
+ while (i<size){
+ output[i] = x;
+ x = x+step;
+ i++;
+ }
+
+ return output;
+ }
+
+ /**
+ * Return the mean of an array
+ */
+ public static double mean(double[] vals){
+ double subtotal = 0;
+ for (int i = 0; i < vals.length; i++ ){
+ if (!Double.isNaN(vals[i])){
+ subtotal += vals[i];
+ }
+ }
+ subtotal = subtotal / vals.length;
+ return subtotal;
+ }
+
+ /**
+ * Returns the maximum value in the array.
+ */
+
+ public static double max(double[] vals) {
+ double m = vals[0];
+ for (int i = 1; i < vals.length; i++)
+ m = Math.max(m, vals[i]);
+ return m;
+ }
+
+ /**
+ * Returns the minimum value in the array.
+ */
+
+ public static double min(double[] vals) {
+ double m = vals[0];
+ for (int i = 1; i < vals.length; i++)
+ m = Math.min(m, vals[i]);
+ return m;
+ }
+
+ /**
+ * Returns the variance of the array of doubles
+ */
+ public static double variance(double[] vals) {
+ double mu = mean(vals);
+ double sumsq = 0.0;
+ double temp = 0;
+ for (int i = 0; i < vals.length; i++){
+ if (!Double.isNaN(vals[i])){
+ temp = (mu - vals[i]);
+ sumsq += temp*temp;
+ }
+ }
+ return sumsq / (vals.length);
+ }
+
+ /**
+ * Returns the standard deviation of an array of doubles
+ */
+ public static double stdev(double[] vals) {
+ return Math.sqrt(variance(vals));
+ }
+
+ /**
+ * Returns the RMS value of an array of doubles
+ */
+ public static double rms(double[] vals) {
+ double m = mean(vals);
+ double s = stdev(vals);
+ return Math.sqrt( m*m + s*s );
+ }
+
+ /**
+ * Returns the integral of a given array calculated by the trapezoidal rule
+ * dt is the time step between each array value. Any NaN values are treated as zero
+ */
+ public static double trapz(double[] y, double dt){
+ double stop = (y.length -1) * dt;
+
+ if (y.length <= 1 || dt <= 0) return 0;
+
+ double[] x = range(0, stop, dt);
+
+ double sum = 0.0;
+ for (int i = 1; i < x.length; i++) {
+ double temp = (x[i] - x[i-1]) * (y[i] + y[i-1]);
+ if (!Double.isNaN(temp)){
+ sum += temp;
+ }
+ }
+ return sum * 0.5;
+ }
+
+ /**
+ * Returns the nearest value in an array to a given value
+ * Search starts from the lowest array index
+ */
+ public static double tnear(double[] range, double near, double start, double step){
+ double min = Double.POSITIVE_INFINITY;
+ int mini = 0;
+
+ //System.out.println("Nearest to "+near+" in range length "+range.length);
+ for (int i=0; i < range.length; i++){
+ double x = Math.abs(range[i] - near);
+ if (x < min){
+ min = x;
+ mini = i;
+ }
+ }
+
+ //System.out.println("Found nearest at i="+mini);
+ return start + (mini*step);
+ }
+
+
+ public static <T> T[] copyOf( T[] original, int length ) {
+ return copyOfRange(original,0,length);
+ }
+
+ /**
+ * Implementation of java.util.Arrays.copyOfRange
+ *
+ * Since Froyo does not include this function it must be implemented here.
+ *
+ * @param original
+ * @param start
+ * @param end
+ * @return
+ */
+ public static <T> T[] copyOfRange( T[] original, int start, int end ) {
+
+ if ( original == null ) {
+ throw new NullPointerException();
+ }
+
+ if ( start < 0 || start > original.length ) {
+ throw new ArrayIndexOutOfBoundsException();
+ }
+
+ if ( start > end ) {
+ throw new IllegalArgumentException();
+ }
+
+ T[] result = (T[]) Array.newInstance( original.getClass().getComponentType(), end-start );
+
+ int index = 0;
+ int stop = original.length < end ? original.length : end;
+ for ( int i = start; i < stop; i ++ ) {
+ if ( i < original.length ) {
+ result[index] = original[i];
+ }
+ index++;
+ }
+
+ return result;
+
+ }
+
+ public static double[] copyOf( double[] original, int length ) {
+ return copyOfRange(original,0,length);
+ }
+
+ public static double[] copyOfRange( double[] original, int start, int end ) {
+
+ if ( original == null ) {
+ throw new NullPointerException();
+ }
+
+ if ( start < 0 || start > original.length ) {
+ throw new ArrayIndexOutOfBoundsException();
+ }
+
+ if ( start > end ) {
+ throw new IllegalArgumentException();
+ }
+
+ double[] result = new double[(end-start)];
+
+ int index = 0;
+ int stop = original.length < end ? original.length : end;
+ for ( int i = start; i < stop; i ++ ) {
+ if ( i < original.length ) {
+ result[index] = original[i];
+ }
+ index++;
+ }
+
+ return result;
+
+ }
+
+ public static byte[] copyOf( byte[] original, int length ) {
+ return copyOfRange(original,0,length);
+ }
+
+ public static byte[] copyOfRange( byte[] original, int start, int end ) {
+
+ if ( original == null ) {
+ throw new NullPointerException();
+ }
+
+ if ( start < 0 || start > original.length ) {
+ throw new ArrayIndexOutOfBoundsException();
+ }
+
+ if ( start > end ) {
+ throw new IllegalArgumentException();
+ }
+
+ byte[] result = new byte[(end-start)];
+
+ int index = 0;
+ int stop = original.length < end ? original.length : end;
+ for ( int i = start; i < stop; i ++ ) {
+ if ( i < original.length ) {
+ result[index] = original[i];
+ }
+ index++;
+ }
+
+ return result;
+
+ }
+
+}
+
projects / debian / openrocket / blobdiff