Java IndexIterator.next方法代码示例

import ucar.ma2.IndexIterator; //导入方法依赖的package包/类
/**
 * Return the identity array - a square array with ones on the main
 * diagonal.
 *
 * @param n Number of rows (and columns) in n x n output.
 * @param dtype Data type
 * @return Identity array
 */
public static Array identity(int n, String dtype) {
    DataType dt = toDataType(dtype);
    int[] shape = new int[]{n, n};
    Array a = Array.factory(dt, shape);
    IndexIterator index = a.getIndexIterator();
    int[] current;
    while (index.hasNext()) {
        index.next();
        current = index.getCurrentCounter();
        if (current[0] == current[1]) {
            index.setObjectCurrent(1);
        } else {
            index.setObjectCurrent(0);
        }
    }

    return a;
}
 

import ucar.ma2.IndexIterator; //导入方法依赖的package包/类
/**
 * Return a 2-D array with ones on the diagonal and zeros elsewhere.
 *
 * @param n Number of rows in the output.
 * @param m Number of columns in the output.
 * @param k Index of the diagonal: 0 (the default) refers to the main
 * diagonal, a positive value refers to an upper diagonal, and a negative
 * value to a lower diagonal.
 * @param dtype Data type
 * @return Created array
 */
public static Array eye(int n, int m, int k, String dtype) {
    DataType dt = toDataType(dtype);
    int[] shape = new int[]{n, m};
    Array a = Array.factory(dt, shape);
    IndexIterator index = a.getIndexIterator();
    int[] current;
    int i, j;
    while (index.hasNext()) {
        index.next();
        current = index.getCurrentCounter();
        i = current[0];
        j = current[1] - k;
        if (i == j) {
            index.setObjectCurrent(1);
        } else {
            index.setObjectCurrent(0);
        }
    }

    return a;
}
 

import ucar.ma2.IndexIterator; //导入方法依赖的package包/类
/**
 * Set section
 *
 * @param a Array a
 * @param ranges Ranges
 * @param v Array value
 * @return Result array
 * @throws InvalidRangeException
 */
public static Array setSection(Array a, List<Range> ranges, Array v) throws InvalidRangeException {
    Array r = a.section(ranges);
    IndexIterator iter = r.getIndexIterator();
    //int[] current;
    Index index = v.getIndex();
    while (iter.hasNext()) {
        iter.next();
        //current = iter.getCurrentCounter();
        //index.set(current);
        iter.setObjectCurrent(v.getObject(index));
        index.incr();
    }
    r = Array.factory(a.getDataType(), a.getShape(), r.getStorage());
    return r;
}
 

import ucar.ma2.IndexIterator; //导入方法依赖的package包/类
/**
 * Take elements from an array along an axis.
 *
 * @param a The array
 * @param ranges The indices of the values to extract.
 * @return The returned array has the same type as a.
 */
public static Array take(Array a, List<Object> ranges) {
    int n = a.getRank();
    int[] shape = new int[n];
    List<List<Integer>> indexlist = new ArrayList<>();
    List<Integer> list;
    for (int i = 0; i < n; i++) {
        Object k = ranges.get(i);
        if (k instanceof Range) {
            Range kr = (Range) k;
            shape[i] = kr.length();
            list = new ArrayList<>();
            for (int j = kr.first(); j <= kr.last(); j += kr.stride()) {
                list.add(j);
            }
            indexlist.add(list);
        } else {
            List<Integer> kl = (List<Integer>) k;
            shape[i] = kl.size();
            indexlist.add(kl);
        }
    }

    Array r = Array.factory(a.getDataType(), shape);
    IndexIterator ii = r.getIndexIterator();
    int[] current, acurrent = new int[n];
    Index index = a.getIndex();
    while (ii.hasNext()) {
        ii.next();
        current = ii.getCurrentCounter();
        for (int i = 0; i < n; i++) {
            acurrent[i] = indexlist.get(i).get(current[i]);
        }
        index.set(acurrent);
        ii.setObjectCurrent(a.getObject(index));
    }

    return r;
}
 

import ucar.ma2.IndexIterator; //导入方法依赖的package包/类
/**
 * Concatenate arrays to one array along a axis
 *
 * @param arrays Array list
 * @param axis The axis
 * @return Concatenated array
 * @throws ucar.ma2.InvalidRangeException
 */
public static Array concatenate(List<Array> arrays, Integer axis) throws InvalidRangeException {
    int ndim = arrays.get(0).getRank();
    if (axis == -1) {
        axis = ndim - 1;
    }
    int len = 0;
    int[] lens = new int[arrays.size()];
    int i = 0;
    List<Index> indexList = new ArrayList<>();
    for (Array a : arrays) {
        len += a.getShape()[axis];
        lens[i] = len;
        indexList.add(Index.factory(a.getShape()));
        i += 1;
    }
    int[] shape = arrays.get(0).getShape();
    shape[axis] = len;
    Array r = Array.factory(arrays.get(0).getDataType(), shape);
    int[] current;
    IndexIterator ii = r.getIndexIterator();
    Index index;
    int idx = 0;
    while (ii.hasNext()) {
        ii.next();
        current = ii.getCurrentCounter();
        for (i = 0; i < lens.length; i++) {
            if (current[axis] < lens[i]) {
                idx = i;
                break;
            }
        }
        if (idx > 0) {
            current[axis] = current[axis] - lens[idx - 1];
        }
        index = indexList.get(idx);
        index.set(current);
        ii.setObjectCurrent(arrays.get(idx).getObject(index));
    }

    return r;
}