On Tuesday 04 April 2006 17:03, John Hunter wrote:
> >>>>> "Steve" == Steve Schmerler <el...@gm...> writes:
>
> Steve> Hi In the plot produced by this here the straight line
> Steve> isn't really straight and seems to "try to interpolate" the
> Steve> data points.
>
>
> Steve> x = linspace(0.016, 0.017, 20) y = 1000*x+5 +
> Steve> randn(len(x))/30.0 p = polyfit(x,y,1) plot(x, y, 'o', x,
> Steve> polyval(p, x), 'r') savefig('image.eps')
>
> Steve> The same happens with p[0]*x+p[1] instead of polyval(p, x).
> Steve> In the corresponding .png is OK so it seems to be a problem
> Steve> with the ps-backend.
>
> This is the same bug that cropped up in your last post -- it is a
> truncation bug in backend ps. 1.4g isn't doing it for us... For
> testing I jacked up all the 1.4g fmt strings to 1.9g and the line
> straightened itself out.
>
> This persistent problem strengthens my belief that the ps backend
> should be outputting transformed coords, since we can then precisely
> know the size of the rounding error, eg in fractions of a point.
I agree. As of svn 2257, the transforms are done by backend_ps, instead of
being passed to the postscript interpreter.
On a side note, may I suggest that svn users should read and post to the
matplotlib-devel list?
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