[sage-support] Re: Mathematical Expression to latex-code-conversion
On Oct 24, 7:15 pm, marko [EMAIL PROTECTED] wrote:
Hello,
I am quite new to SAGE but I think I've found a problem with the
latex(math-expression) command. I've tried with version 2.8.6, 2.8.7
and 2.8.8.1:
The problem seems to be the abs() command. Take any function like
f(x)=2*abs(x) with a changing sign. Entering now latex(f) shows me as
the result:
x \ {\mapsto}\ {2 \cdot \abs \left( x \right)}
That looks like a bug to me.
ticket opened by mhansen: http://www.sagetrac.org/sage_trac/ticket/982
I opened #983, but mhansen was faster :O
Compiling this with LaTeX I cannot see the mathematical sign for abs
( preferred \left| (...) \right| ), but simple brackets. Furthermore
the LaTeX compilers tells me of errors: !undefined control sentence
In fact, \abs is no known latex command to me. Deleting \abs removes
the latex compiler error, of course, but thats not the correct latex
code for my expression for f(x).
The following packages have been included for compiling in latex:
\usepackage{ngerman}
\usepackage{color, framed}
\usepackage{graphicx}
\usepackage{amsmath, amsthm, amssymb}
\usepackage[automark]{scrpage2}
I don't know if I've done something wrong or if this is a bug or if
its even supposed to be that way. So I'ld like to ask you: what can I
do?
How can I get the right result as latex code, if its neccessary to use
absolut values of functions or parts of functions?
Thanks for your help,
Well, thank you for reporting the issue.
marko
Cheers,
Michael
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[sage-support] Re: Mathematical Expression to latex-code-conversion
Hello,
I've fixed this issue and have included the patch below. It will be
in the next release which should be come out in the next few days.
Here is the behavior after the patch:
sage: g(x) = 2*abs(x)
sage: latex(g)
x \ {\mapsto}\ {2 \cdot \left| x \right|}
--Mike
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# HG changeset patch
# User Mike Hansen [EMAIL PROTECTED]
# Date 1193248166 18000
# Node ID ff6836693992d0cdf8513083904cccafb5b9bfa5
# Parent 384cf32899ac4ad7e086bbc3ca53c577d68bd3f1
Fixed #982
diff -r 384cf32899ac -r ff6836693992 sage/calculus/calculus.py
--- a/sage/calculus/calculus.py Tue Oct 23 21:05:54 2007 -0500
+++ b/sage/calculus/calculus.py Wed Oct 24 12:49:26 2007 -0500
@@ -3818,6 +3818,11 @@ class SymbolicComposition(SymbolicOperat
if not self.is_simplified():
return self.simplify()._latex_()
ops = self._operands
+
+#Check to see if the function has a _latex_composition method
+if hasattr(ops[0], '_latex_composition'):
+return ops[0]._latex_composition(ops[1])
+
# certain functions (such as \sqrt) need braces in LaTeX
if (ops[0]).tex_needs_braces():
return r%s{ %s } % ( (ops[0])._latex_(), (ops[1])._latex_())
@@ -4033,7 +4038,17 @@ class Function_abs(PrimitiveFunction):
return abs
def _latex_(self):
-return \\abs
+return \\mathrm{abs}
+
+def _latex_composition(self, x):
+
+sage: f = sage.calculus.calculus.Function_abs()
+sage: latex(f)
+\mathrm{abs}
+sage: latex(abs(x))
+\left| x \right|
+
+return \\left| + latex(x) + \\right|
def _approx_(self, x):
return float(x.__abs__())
