Function PyArray_RemoveSmallest

numpy/core/src/multiarray/iterators.c:344–382

NUMPY_API * Adjusts previously broadcasted iterators so that the axis with * the smallest sum of iterator strides is not iterated over. * Returns dimension which is smallest in the range [0,multi->nd). * A -1 is returned if multi->nd == 0. * * don't use with PyArray_ITER_GOTO1D because factors are not adjusted */

 * don't use with PyArray_ITER_GOTO1D because factors are not adjusted
 */
NPY_NO_EXPORT int
PyArray_RemoveSmallest(PyArrayMultiIterObject *multi)
{
    PyArrayIterObject *it;
    int i, j;
    int axis;
    npy_intp smallest;
    npy_intp sumstrides[NPY_MAXDIMS];

    if (multi->nd == 0) {
        return -1;
    }
    for (i = 0; i < multi->nd; i++) {
        sumstrides[i] = 0;
        for (j = 0; j < multi->numiter; j++) {
            sumstrides[i] += multi->iters[j]->strides[i];
        }
    }
    axis = 0;
    smallest = sumstrides[0];
    /* Find longest dimension */
    for (i = 1; i < multi->nd; i++) {
        if (sumstrides[i] < smallest) {
            axis = i;
            smallest = sumstrides[i];
        }
    }
    for(i = 0; i < multi->numiter; i++) {
        it = multi->iters[i];
        it->contiguous = 0;
        if (it->size != 0) {
            it->size /= (it->dims_m1[axis]+1);
        }
        it->dims_m1[axis] = 0;
        it->backstrides[axis] = 0;
    }
    multi->size = multi->iters[0]->size;
    return axis;
}

/* Returns an array scalar holding the element desired */