Hi all, I have got numpy and gnuplot on speaking terms. But now, trying to use the barchart, I get following error: gnuplot> set style histogram clustered gap 5 title offset character 0, 0, 0 ^ line 0: expecting 'data', 'function', 'line', 'fill' or 'arrow' line 0: undefined variable: in line 0: undefined variable: invert gnuplot> set style data histograms ^ line 0: expecting 'lines', 'points', 'linespoints', 'dots', 'impulses', 'yerrorbars', 'xerrorbars', 'xyerrorbars', 'steps', 'fsteps', 'histeps', 'filledcurves', 'boxes', 'boxerrorbars', 'boxxyerrorbars', 'vectors', 'financebars', 'candlesticks', 'errorlines', 'xerrorlines', 'yerrorlines', 'xyerrorlines', 'pm3d' Gnuplot is working from commandline and has version 4.0. Thanks for any suggestion! Joachim