X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=core%2Fsrc%2Fnet%2Fsf%2Fopenrocket%2Futil%2FArrayUtils.java;h=7d373096a3cae4930e878b4f47de9521f0137628;hb=ed703c494f30cb24f14aad96d9c8ad9f8f8fd332;hp=4202c53ce8623389b872f8184e69a866b171b793;hpb=953ac8ca75bc3bdcb9db8a382c7b3d63c795b27a;p=debian%2Fopenrocket

diff --git a/core/src/net/sf/openrocket/util/ArrayUtils.java b/core/src/net/sf/openrocket/util/ArrayUtils.java
index 4202c53c..7d373096 100644
--- a/core/src/net/sf/openrocket/util/ArrayUtils.java
+++ b/core/src/net/sf/openrocket/util/ArrayUtils.java
@@ -4,6 +4,136 @@ 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++ ){
+			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++){
+			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
+	 */
+	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++) {
+	        sum += (x[i] - x[i-1]) * (y[i] + y[i-1]);
+	    }
+	    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
 	 * 
@@ -42,5 +172,72 @@ public class ArrayUtils {
 		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;
+		
+	}
+
 }
+