Function reduce_loop

numpy/core/src/umath/ufunc_object.c:2925–3015

static int
reduce_loop(PyArrayMethod_Context *context,
        PyArrayMethod_StridedLoop *strided_loop, NpyAuxData *auxdata,
        NpyIter *iter, char **dataptrs, npy_intp const *strides,
        npy_intp const *countptr, NpyIter_IterNextFunc *iternext,
        int needs_api, npy_intp skip_first_count)
{
    int retval = 0;
    char *dataptrs_copy[4];
    npy_intp strides_copy[4];
    npy_bool masked;

    NPY_BEGIN_THREADS_DEF;
    /* Get the number of operands, to determine whether "where" is used */
    masked = (NpyIter_GetNOp(iter) == 3);

    if (!needs_api) {
        NPY_BEGIN_THREADS_THRESHOLDED(NpyIter_GetIterSize(iter));
    }

    if (skip_first_count > 0) {
        assert(!masked);  /* Path currently not available for masked */
        while (1) {
            npy_intp count = *countptr;

            /* Skip any first-visit elements */
            if (NpyIter_IsFirstVisit(iter, 0)) {
                if (strides[0] == 0) {
                    --count;
                    --skip_first_count;
                    dataptrs[1] += strides[1];
                }
                else {
                    skip_first_count -= count;
                    count = 0;
                }
            }
            if (count > 0) {
                /* Turn the two items into three for the inner loop */
                dataptrs_copy[0] = dataptrs[0];
                dataptrs_copy[1] = dataptrs[1];
                dataptrs_copy[2] = dataptrs[0];
                strides_copy[0] = strides[0];
                strides_copy[1] = strides[1];
                strides_copy[2] = strides[0];

                retval = strided_loop(context,
                        dataptrs_copy, &count, strides_copy, auxdata);
                if (retval < 0) {
                    goto finish_loop;
                }
            }

            /* Advance loop, and abort on error (or finish) */
            if (!iternext(iter)) {
                goto finish_loop;
            }