org.nd4j.linalg.api.shape.StridePermutation Maven / Gradle / Ivy
package org.nd4j.linalg.api.shape;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
/**
* Metadata for striding
* mainly meant for internal use
*
* @author Adam Gibson
*/
public @Data @AllArgsConstructor @NoArgsConstructor class StridePermutation implements Comparable {
private int permutation;
private int stride;
@Override
public int compareTo(StridePermutation o) {
int astride = this.stride, bstride = o.getStride();
/* Sort the absolute value of the strides */
if (astride < 0) {
astride = -astride;
}
if (bstride < 0) {
bstride = -bstride;
}
if (astride == bstride) {
/*
* Make the qsort stable by next comparing the perm order.
* (Note that two perm entries will never be equal)
*/
int aperm = permutation, bperm = o.getPermutation();
return (aperm < bperm) ? -1 : 1;
}
if (astride > bstride) {
return -1;
}
return 1;
}
/**
* Create an array of these from the given stride
* @param stride the stride
* @return the stride permutation array
*/
public static StridePermutation[] create(int[] stride) {
StridePermutation[] ret = new StridePermutation[stride.length];
for (int i = 0; i < stride.length; i++) {
ret[i] = new StridePermutation(i, stride[i]);
}
return ret;
}
}