test_technical.py 文件源码

def expected_bbands(self, window_length, k, closes):
        """Compute the expected data (without adjustments) for the given
        window, k, and closes array.

        This uses talib.BBANDS to generate the expected data.
        """
        lower_cols = []
        middle_cols = []
        upper_cols = []

        ndates, nassets = closes.shape

        for n in range(nassets):
            close_col = closes[:, n]
            if np.isnan(close_col).all():
                # ta-lib doesn't deal well with all nans.
                upper, middle, lower = [np.full(ndates, np.nan)] * 3
            else:
                upper, middle, lower = talib.BBANDS(
                    close_col,
                    window_length,
                    k,
                    k,
                )

            upper_cols.append(upper)
            middle_cols.append(middle)
            lower_cols.append(lower)

        # Stack all of our uppers, middles, lowers into three 2d arrays
        # whose columns are the sids. After that, slice off only the
        # rows we care about.
        where = np.s_[window_length - 1:]
        uppers = np.column_stack(upper_cols)[where]
        middles = np.column_stack(middle_cols)[where]
        lowers = np.column_stack(lower_cols)[where]
        return uppers, middles, lowers