def __init__(self, endog, endog_lagged, params, sigma_u, lag_order,
                 model=None, trend='c', names=None, dates=None):

        self.model = model
        self.y = self.endog = endog  #keep alias for now
        self.ys_lagged = self.endog_lagged = endog_lagged #keep alias for now
        self.dates = dates

        self.n_totobs, neqs = self.y.shape
        self.nobs = self.n_totobs - lag_order
        k_trend = util.get_trendorder(trend)
        if k_trend > 0: # make this the polynomial trend order
            trendorder = k_trend - 1
        else:
            trendorder = None
        self.k_trend = k_trend
        self.trendorder = trendorder
        self.exog_names = util.make_lag_names(names, lag_order, k_trend)
        self.params = params

        # Initialize VARProcess parent class
        # construct coefficient matrices
        # Each matrix needs to be transposed
        reshaped = self.params[self.k_trend:]
        reshaped = reshaped.reshape((lag_order, neqs, neqs))

        # Need to transpose each coefficient matrix
        intercept = self.params[0]
        coefs = reshaped.swapaxes(1, 2).copy()

        super(VARResults, self).__init__(coefs, intercept, sigma_u, names=names)

    def fit(self, maxlags=None, method='ols', ic=None, trend='c',
            verbose=False):
        """
        Fit the VAR model

        Parameters
        ----------
        maxlags : int
            Maximum number of lags to check for order selection, defaults to
            12 * (nobs/100.)**(1./4), see select_order function
        method : {'ols'}
            Estimation method to use
        ic : {'aic', 'fpe', 'hqic', 'bic', None}
            Information criterion to use for VAR order selection.
            aic : Akaike
            fpe : Final prediction error
            hqic : Hannan-Quinn
            bic : Bayesian a.k.a. Schwarz
        verbose : bool, default False
            Print order selection output to the screen
        trend, str {"c", "ct", "ctt", "nc"}
            "c" - add constant
            "ct" - constant and trend
            "ctt" - constant, linear and quadratic trend
            "nc" - co constant, no trend
            Note that these are prepended to the columns of the dataset.

        Notes
        -----
        Lutkepohl pp. 146-153

        Returns
        -------
        est : VARResults
        """
        lags = maxlags

        if trend not in ['c', 'ct', 'ctt', 'nc']:
            raise ValueError("trend '{}' not supported for VAR".format(trend))

        if ic is not None:
            selections = self.select_order(maxlags=maxlags, verbose=verbose)
            if ic not in selections:
                raise Exception("%s not recognized, must be among %s"
                                % (ic, sorted(selections)))
            lags = selections[ic]
            if verbose:
                print('Using %d based on %s criterion' %  (lags, ic))
        else:
            if lags is None:
                lags = 1

        k_trend = util.get_trendorder(trend)
        self.exog_names = util.make_lag_names(self.endog_names, lags, k_trend)
        self.nobs = len(self.endog) - lags

        return self._estimate_var(lags, trend=trend)

def test_get_trendorder():
    results = {
        'c' : 1,
        'nc' : 0,
        'ct' : 2,
        'ctt' : 3
    }

    for t, trendorder in results.iteritems():
        assert(util.get_trendorder(t) == trendorder)

    def __init__(
        self,
        endog,
        endog_lagged,
        params,
        sigma_u,
        lag_order,
        A=None,
        B=None,
        A_mask=None,
        B_mask=None,
        model=None,
        trend="c",
        names=None,
        dates=None,
    ):

        self.model = model
        self.y = self.endog = endog  # keep alias for now
        self.ys_lagged = self.endog_lagged = endog_lagged  # keep alias for now
        self.dates = dates

        self.n_totobs, self.neqs = self.y.shape
        self.nobs = self.n_totobs - lag_order
        k_trend = util.get_trendorder(trend)
        if k_trend > 0:  # make this the polynomial trend order
            trendorder = k_trend - 1
        else:
            trendorder = None
        self.k_trend = k_trend
        self.trendorder = trendorder

        self.exog_names = util.make_lag_names(names, lag_order, k_trend)
        self.params = params
        self.sigma_u = sigma_u

        # Each matrix needs to be transposed
        reshaped = self.params[self.k_trend :]
        reshaped = reshaped.reshape((lag_order, self.neqs, self.neqs))

        # Need to transpose each coefficient matrix
        intercept = self.params[0]
        coefs = reshaped.swapaxes(1, 2).copy()

        # SVAR components
        # TODO: if you define these here, you don't also have to define
        # them in SVAR process, but I left them for now -ss
        self.A = A
        self.B = B
        self.A_mask = A_mask
        self.B_mask = B_mask

        super(SVARResults, self).__init__(coefs, intercept, sigma_u, A, B, names=names)

    def _stackX(self, k_ar, trend):
        """
        Private method to build the RHS matrix for estimation.

        Columns are trend terms then lags.
        """
        endog = self.endog
        X = lagmat(endog, maxlag=k_ar, trim='both')
        k_trend = util.get_trendorder(trend)
        if k_trend:
            X = add_trend(X, prepend=True, trend=trend)
        self.k_trend = k_trend
        return X

    def _estimate_svar(self, start_params, lags, maxiter, maxfun, trend="c", solver="nm", override=False):
        """
        lags : int
        trend : string or None
            As per above
        """
        k_trend = util.get_trendorder(trend)
        y = self.endog
        z = util.get_var_endog(y, lags, trend=trend)
        y_sample = y[lags:]

        # Lutkepohl p75, about 5x faster than stated formula
        var_params = np.linalg.lstsq(z, y_sample)[0]
        resid = y_sample - np.dot(z, var_params)

        # Unbiased estimate of covariance matrix $\Sigma_u$ of the white noise
        # process $u$
        # equivalent definition
        # .. math:: \frac{1}{T - Kp - 1} Y^\prime (I_T - Z (Z^\prime Z)^{-1}
        # Z^\prime) Y
        # Ref: Lutkepohl p.75
        # df_resid right now is T - Kp - 1, which is a suggested correction

        avobs = len(y_sample)

        df_resid = avobs - (self.neqs * lags + k_trend)

        sse = np.dot(resid.T, resid)
        # TODO: should give users the option to use a dof correction or not
        omega = sse / df_resid
        self.sigma_u = omega

        A, B = self._solve_AB(start_params, override=override, solver=solver, maxiter=maxiter, maxfun=maxfun)
        A_mask = self.A_mask
        B_mask = self.B_mask

        return SVARResults(
            y,
            z,
            var_params,
            omega,
            lags,
            names=self.endog_names,
            trend=trend,
            dates=self.data.dates,
            model=self,
            A=A,
            B=B,
            A_mask=A_mask,
            B_mask=B_mask,
        )

    def _estimate_var(self, lags, offset=0, trend="c"):
        """
        lags : int
        offset : int
            Periods to drop from beginning-- for order selection so it's an
            apples-to-apples comparison
        trend : string or None
            As per above
        """
        # have to do this again because select_order doesn't call fit
        self.k_trend = k_trend = util.get_trendorder(trend)

        if offset < 0:  # pragma: no cover
            raise ValueError("offset must be >= 0")

        y = self.y[offset:]

        z = util.get_var_endog(y, lags, trend=trend)
        y_sample = y[lags:]

        # Lutkepohl p75, about 5x faster than stated formula
        params = np.linalg.lstsq(z, y_sample)[0]
        resid = y_sample - np.dot(z, params)

        # Unbiased estimate of covariance matrix $\Sigma_u$ of the white noise
        # process $u$
        # equivalent definition
        # .. math:: \frac{1}{T - Kp - 1} Y^\prime (I_T - Z (Z^\prime Z)^{-1}
        # Z^\prime) Y
        # Ref: Lutkepohl p.75
        # df_resid right now is T - Kp - 1, which is a suggested correction

        avobs = len(y_sample)

        df_resid = avobs - (self.neqs * lags + k_trend)

        sse = np.dot(resid.T, resid)
        omega = sse / df_resid

        varfit = VARResults(
            y, z, params, omega, lags, names=self.endog_names, trend=trend, dates=self.data.dates, model=self
        )
        return VARResultsWrapper(varfit)

    def predict(self, params, start=None, end=None, lags=1, trend='c'):
        """
        Returns in-sample predictions or forecasts
        """
        if start is None:
            start = k_ar

        # Handle start, end
        start, end, out_of_sample, prediction_index = (
            self._get_prediction_index(start, end))

        if end < start:
            raise ValueError("end is before start")
        if end == start + out_of_sample:
            return np.array([])

        k_trend = util.get_trendorder(trend)
        k = self.neqs
        k_ar = lags

        predictedvalues = np.zeros((end + 1 - start + out_of_sample, k))
        if k_trend != 0:
            intercept = params[:k_trend]
            predictedvalues += intercept

        y = self.y
        X = util.get_var_endog(y, lags, trend=trend, has_constant='raise')
        fittedvalues = np.dot(X, params)

        fv_start = start - k_ar
        pv_end = min(len(predictedvalues), len(fittedvalues) - fv_start)
        fv_end = min(len(fittedvalues), end-k_ar+1)
        predictedvalues[:pv_end] = fittedvalues[fv_start:fv_end]

        if not out_of_sample:
            return predictedvalues

        # fit out of sample
        y = y[-k_ar:]
        coefs = params[k_trend:].reshape((k_ar, k, k)).swapaxes(1,2)
        predictedvalues[pv_end:] = forecast(y, coefs, intercept, out_of_sample)
        return predictedvalues

    def __init__(self, data, lag_order=1, window=None, window_type='expanding',
                 trend='c', min_periods=None):
        self.lag_order = lag_order
        self.neqs = len(data.columns)

        self._y_orig = data

        # TODO: deal with trend
        self._x_orig = _make_lag_matrix(data, lag_order)
        self._x_orig['intercept'] = 1

        (self.y, self.x, self.x_filtered, self._index,
         self._time_has_obs) = _filter_data(self._y_orig, self._x_orig)

        self.lag_order = lag_order
        self.trendorder = util.get_trendorder(trend)

        self._set_window(window_type, window, min_periods)

        warnings.warn('DynamicPanelVAR is depricated and will be removed in a future version, use VAR or VARMAX.', DeprecationWarning)

def test_get_trendorder():
    results = {"c": 1, "nc": 0, "ct": 2, "ctt": 3}

    for t, trendorder in results.iteritems():
        assert util.get_trendorder(t) == trendorder