Function PyArray_Arange

numpy/core/src/multiarray/ctors.c:2941–3023

NUMPY_API Arange, */

  Arange,
*/
NPY_NO_EXPORT PyObject *
PyArray_Arange(double start, double stop, double step, int type_num)
{
    npy_intp length;
    PyArrayObject *range;
    PyArray_ArrFuncs *funcs;
    PyObject *obj;
    int ret;
    double delta, tmp_len;
    NPY_BEGIN_THREADS_DEF;

    delta = stop - start;
    tmp_len = delta/step;

    /* Underflow and divide-by-inf check */
    if (tmp_len == 0.0 && delta != 0.0) {
        if (npy_signbit(tmp_len)) {
            length = 0;
        }
        else {
            length = 1;
        }
    }
    else {
        length = _arange_safe_ceil_to_intp(tmp_len);
        if (error_converting(length)) {
            return NULL;
        }
    }

    if (length <= 0) {
        length = 0;
        return PyArray_New(&PyArray_Type, 1, &length, type_num,
                           NULL, NULL, 0, 0, NULL);
    }
    range = (PyArrayObject *)PyArray_New(&PyArray_Type, 1, &length, type_num,
                        NULL, NULL, 0, 0, NULL);
    if (range == NULL) {
        return NULL;
    }
    funcs = PyArray_DESCR(range)->f;

    /*
     * place start in the buffer and the next value in the second position
     * if length > 2, then call the inner loop, otherwise stop
     */
    obj = PyFloat_FromDouble(start);
    ret = funcs->setitem(obj, PyArray_DATA(range), range);
    Py_DECREF(obj);
    if (ret < 0) {
        goto fail;
    }
    if (length == 1) {
        return (PyObject *)range;
    }
    obj = PyFloat_FromDouble(start + step);
    ret = funcs->setitem(obj, PyArray_BYTES(range)+PyArray_ITEMSIZE(range),
                         range);