Function npyiter_check_casting

numpy/core/src/multiarray/nditer_constr.c:1294–1354

static int
npyiter_check_casting(int nop, PyArrayObject **op,
                    PyArray_Descr **op_dtype,
                    NPY_CASTING casting,
                    npyiter_opitflags *op_itflags)
{
    int iop;

    for(iop = 0; iop < nop; ++iop) {
        NPY_IT_DBG_PRINT1("Iterator: Checking casting for operand %d\n",
                            (int)iop);
#if NPY_IT_DBG_TRACING
        printf("op: ");
        if (op[iop] != NULL) {
            PyObject_Print((PyObject *)PyArray_DESCR(op[iop]), stdout, 0);
        }
        else {
            printf("<null>");
        }
        printf(", iter: ");
        PyObject_Print((PyObject *)op_dtype[iop], stdout, 0);
        printf("\n");
#endif
        /* If the types aren't equivalent, a cast is necessary */
        if (op[iop] != NULL && !PyArray_EquivTypes(PyArray_DESCR(op[iop]),
                                                     op_dtype[iop])) {
            /* Check read (op -> temp) casting */
            if ((op_itflags[iop] & NPY_OP_ITFLAG_READ) &&
                        !PyArray_CanCastArrayTo(op[iop],
                                          op_dtype[iop],
                                          casting)) {
                PyErr_Format(PyExc_TypeError,
                        "Iterator operand %d dtype could not be cast from "
                        "%R to %R according to the rule %s",
                        iop, PyArray_DESCR(op[iop]), op_dtype[iop],
                        npyiter_casting_to_string(casting));
                return 0;
            }
            /* Check write (temp -> op) casting */
            if ((op_itflags[iop] & NPY_OP_ITFLAG_WRITE) &&
                        !PyArray_CanCastTypeTo(op_dtype[iop],
                                          PyArray_DESCR(op[iop]),
                                          casting)) {
                PyErr_Format(PyExc_TypeError,
                        "Iterator requested dtype could not be cast from "
                        "%R to %R, the operand %d dtype, "
                        "according to the rule %s",
                        op_dtype[iop], PyArray_DESCR(op[iop]), iop,
                        npyiter_casting_to_string(casting));
                return 0;
            }

            NPY_IT_DBG_PRINT("Iterator: Setting NPY_OP_ITFLAG_CAST "
                                "because the types aren't equivalent\n");
            /* Indicate that this operand needs casting */
            op_itflags[iop] |= NPY_OP_ITFLAG_CAST;
        }
    }