amplitudecosinetaper.java

一个用java写的地震分析软件(无源码)-used to write a seismic analysis software (without source)

package org.trinet.util;
/** Apply a cosine taper to a time series. */
public class AmplitudeCosineTaper {

    public static double [] getTaperWeights(int nsamples, double alpha) {
    /* alpha between 0. and 1.*/
        //double pi = 4.0 * Math.atan(1.0);
        double pi = Math.PI;
        int midPoint = (nsamples-1)/2;
        int taperLength = (int)((alpha * nsamples)/2.);
        double [] w = new double[taperLength];
        for (int idx =0; idx < taperLength; idx++) {
            double fraction = ((double) idx - alpha*midPoint)/(alpha*midPoint);
            w[idx] = 0.5*(1.0 + Math.cos(pi * fraction));
        }
        return w;
    }
    /** Apply a cosine taper to a float[] time series. */
    public static float [] taper(float [] inValues, double alpha) {
    /* alpha between 0. and 1.*/
        //double pi = 4.0 * Math.atan(1.0);
        int nsamples = inValues.length;
        int midPoint = (nsamples-1)/2;
        int taperLength = (int)((alpha * nsamples)/2.);
        float [] outValues = inValues;
        for (int idx =0; idx < taperLength; idx++) {
            double fraction = ((double) idx - alpha*midPoint)/(alpha*midPoint);
            double weight = 0.5*(1.0 + Math.cos(Math.PI * fraction));
            outValues[idx] = (float) (weight*inValues[idx]);
            outValues[nsamples-idx-1] = (float) (weight*inValues[nsamples-idx-1]);
        }
        return outValues;
    }
    /** Apply a cosine taper to an int[] time series. */
    public static int [] taper(int [] inValues, double alpha) {
    /* alpha between 0. and 1.*/
        //double pi = 4.0 * Math.atan(1.0);
        int nsamples = inValues.length;
        int midPoint = (nsamples-1)/2;
        int taperLength = (int)((alpha * nsamples)/2.);
        int [] outValues = inValues;
        for (int idx =0; idx < taperLength; idx++) {
            double fraction = ((double) idx - alpha*midPoint)/(alpha*midPoint);
            double weight = 0.5*(1.0 + Math.cos(Math.PI * fraction));
            outValues[idx] = (int) (weight*inValues[idx]);
            outValues[nsamples-idx-1] = (int) (weight*inValues[nsamples-idx-1]);
        }
        return outValues;
    }

    public static final void main(String args []) {
        int [] data = new int [1000];
        java.util.Arrays.fill(data, 1000);
        double [] wts = AmplitudeCosineTaper.getTaperWeights(500, 0.1);
        int size = wts.length;
        for (int idx=0; idx<size; idx++) {
           System.out.print(wts[idx]);
           System.out.print(", ");
           if (idx>0 && idx%10 == 0) System.out.println();
        }
        System.out.println();
        data = taper(data, 0.1);
        size = data.length;
        for (int idx=0; idx<size; idx++) {
           System.out.print(data[idx]);
           System.out.print(" ");
           if (idx>0 && idx%10 == 0) System.out.println();
        }
    }
}