Using the example code "Building a Model for Forecasting Stock Prizes" (see https://www.wolfram.com/mathematica/new-in-10/time-series/build-a-model-for-forecasting-stock-prices.html) which was working before gives errors in Mathematica V12.0. The code is
data = FinancialData["SBUX",
"Close", {{2013, 1, 1}, {2013, 8, 1}, "Week"}, "Value"];
start = DayRound["Jan 1 2013", "BusinessDay", "Next"];
stocks = TimeSeries[data, {start, Automatic, "Week"}]
DateListPlot[stocks, Filling -> Axis]
eproc = TimeSeriesModelFit[stocks]
forecast = TimeSeriesForecast[eproc, {4}];
DateListPlot[{stocks, forecast}, Filling -> Axis]
The TimeSeries function stocks = TimeSeries[data, {start, Automatic, "Week"}] results in multiple error messages. First one and route cause is
DateListPlot::ldata: TimeSeries[TimeSeries[Time: 04 Jan 2013 to 01 Aug 2013 \[SpanFromLeft]
Data points: 31 \[SpanFromLeft]
],{DateObject[{2013,1,2},Day,Gregorian,2.],Automatic,Week}] is not a valid dataset or list of datasets.
If I remove the bracket {start, Automatic, "Week"} in TimeSeries everything seems to work with the exeption that I now get a message
TemporalData::rsmplng: The data is not uniformly spaced and will be automatically resampled to the resolution of the minimum time increment.
The resulting diagrams seem to be O.K.
Could not find any hint in the documentation. Therefore I appreciate any help from the experts.
Thanks, Walter