/**
* Computes the standard packed array strides for a given shape.
*
* @param shape the shape of a matrix:
* @param startValue the startValue for the strides
* @return the strides for a matrix of n dimensions
*/
public static int[] calcStrides(int[] shape, int startValue) {
if (Shape.isColumnVectorShape(shape)) {
int[] ret = new int[2];
Arrays.fill(ret, startValue);
return ret;
}
if (Shape.isRowVectorShape(shape)) {
int[] ret = new int[2];
ret[0] = 1;
ret[1] = shape[0];
return ret;
}
int dimensions = shape.length;
int[] stride = new int[dimensions];
int st = startValue;
for (int j = dimensions - 1; j >= 0; j--) {
stride[j] = st;
st *= shape[j];
}
if (dimensions > 2 && shape[0] == 1) {
stride = ArrayUtil.reverseCopy(stride);
}
return stride;
}
/**
* Computes the standard packed array strides for a given shape.
*
* @param shape the shape of a matrix:
* @param startNum the start number for the strides
* @return the strides for a matrix of n dimensions
*/
public static int[] calcStridesFortran(int[] shape, int startNum) {
if (Shape.isColumnVectorShape(shape)) {
int[] ret = new int[2];
Arrays.fill(ret, startNum);
return ret;
}
int dimensions = shape.length;
int[] stride = new int[dimensions];
int st = startNum;
for (int j = 0; j < stride.length; j++) {
stride[j] = st;
st *= shape[j];
}
if (dimensions > 2 && shape[0] == 1) {
stride = ArrayUtil.reverseCopy(stride);
}
return stride;
}
