I just got a doc test failure on Solaris.
File
"/export/home/drkirkby/32/sage-4.3.4.alpha0/devel/sage/sage/plot/colors.py",
line 660:
sage: gold / pi + yellow * e
Expected:
RGB color (0.51829585732141792, 0.49333037605210095, 0.0)
Got:
RGB color (0.51829585732141814, 0.49333037605210117, 0.0)
Looking at the doc test I see this:
--------------------------------------
EXAMPLES::
sage: from __future__ import division
sage: from sage.plot.colors import yellow, gold
sage: yellow / 4
RGB color (0.25, 0.25, 0.0)
sage: yellow.__truediv__(4)
RGB color (0.25, 0.25, 0.0)
sage: gold / pi + yellow * e
RGB color (0.51829585732141792, 0.49333037605210095, 0.0)
----------------------------------------------
The is absolutely no justification given in the doc test for this result, so how
do we know it's right?
Printing the values of 'yellow' and 'gold' I get:
sage: print yellow
RGB color (1.0, 1.0, 0.0)
sage: print gold
RGB color (1.0, 0.84313725490196079, 0.0)
sage:
I personally don't understand how one can divide one colour by another, but I'm
not disputing that there can be some logic in this. I tried in Mathematica to
just divide the these as lists
In[44]:= yellow={1,1,0}
Out[44]= {1, 1, 0}
In[45]:= gold={1.0,0.84313725490196079, 0.0}
In[46]:= gold/Pi + yellow E
Out[46]= {3.03659, 2.98666, 0.}
With no idea what this division is supposed to do, I tried.
In[47]:= Normalize[%]
Out[47]= {0.712944, 0.701221, 0.}
but that gives totally different numbers.
So I'm none the wiser. Of course, I could create a ticket to check the expected
value to be
0.51829585732141..., 0.49333037605210...,0.0
but I'd have no justification for this.
Perhaps someone can enlighten me how one divides /multiples colours, and can
show me a high precision value for the result.
This is just one of several examples I've seen in Sage where the numeric result
from a doc test is not obvious. The "Expected" value is probably what someone
got on their computer. I "Got" a different value on my computer. But who knows
what the result should be? Without some justification, I find it hard to believe
this doc test achieves very much. I've just waisted an hour trying to work out
how I might reproduce this, but can't
Dave
Dave
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