Function PyArray_Transpose

numpy/core/src/multiarray/shape.c:668–732

NUMPY_API * Return Transpose. */

 * Return Transpose.
 */
NPY_NO_EXPORT PyObject *
PyArray_Transpose(PyArrayObject *ap, PyArray_Dims *permute)
{
    npy_intp *axes;
    int i, n;
    int permutation[NPY_MAXDIMS], reverse_permutation[NPY_MAXDIMS];
    PyArrayObject *ret = NULL;
    int flags;

    if (permute == NULL) {
        n = PyArray_NDIM(ap);
        for (i = 0; i < n; i++) {
            permutation[i] = n-1-i;
        }
    }
    else {
        n = permute->len;
        axes = permute->ptr;
        if (n != PyArray_NDIM(ap)) {
            PyErr_SetString(PyExc_ValueError,
                            "axes don't match array");
            return NULL;
        }
        for (i = 0; i < n; i++) {
            reverse_permutation[i] = -1;
        }
        for (i = 0; i < n; i++) {
            int axis = axes[i];
            if (check_and_adjust_axis(&axis, PyArray_NDIM(ap)) < 0) {
                return NULL;
            }
            if (reverse_permutation[axis] != -1) {
                PyErr_SetString(PyExc_ValueError,
                                "repeated axis in transpose");
                return NULL;
            }
            reverse_permutation[axis] = i;
            permutation[i] = axis;
        }
    }

    flags = PyArray_FLAGS(ap);

    /*
     * this allocates memory for dimensions and strides (but fills them
     * incorrectly), sets up descr, and points data at PyArray_DATA(ap).
     */
    Py_INCREF(PyArray_DESCR(ap));
    ret = (PyArrayObject *) PyArray_NewFromDescrAndBase(
            Py_TYPE(ap), PyArray_DESCR(ap),
            n, PyArray_DIMS(ap), NULL, PyArray_DATA(ap),
            flags, (PyObject *)ap, (PyObject *)ap);
    if (ret == NULL) {
        return NULL;
    }

    /* fix the dimensions and strides of the return-array */
    for (i = 0; i < n; i++) {