Am Freitag, 7. Mai 2010, um 05:54:50 schrieb ablondin:
> Ok, I think I understand your problem. I had something similar
> before. The problem is that the object returned by the function
> sarrus is a 'str',
> which sagetex format so that it replaces every underscore, etc.
> with \_ to make it work in Latex. If you don't want the output
> to be modified,
> you have to use LatexExpr object
>
> def sarrus(A):
> bracket_neg = lambda i:str(i) if i >= 0 else '(' + str(i) +
> ')' res = '['
>
> for i in range(3):
> for j in range(3):
> a_ij = A[j, (i+j)%3]
> if j > 0: res += ' \\cdot '
> res += bracket_neg(a_ij)
> if i < 2: res += ' + '
>
> res += '] - ['
>
> for i in range(3):
> for j in range(3):
> a_ij = A[j, (2-i-j)%3]
> if j > 0: res += ' \\cdot '
> res += bracket_neg(a_ij)
> if i < 2: res += ' + '
>
> res += ']'
>
> from sage.misc.latex import LatexExpr
> return LatexExpr(res)
>
> and when you call \sage{sarrus(A)}, you must put in between
> dollar signs. Feel free to ask further if it doesn't solve your
> problem !
Thanks, that is exactly what i was looking for.
Georg
> On 6 mai, 10:29, "Georg Damm" <georg.d...@web.de> wrote:
> > Hi Alex,
> >
> > > If I understand correctly your question, you would like to
> > > convert arithmetical expressions directly into Latex.
> >
> > I would like to convert a string into a sage-Latex-expression
> > (in sagetex).
> >
> > > I don't know if it is possible to do it in Sage, but you
> > > could always write your own function. I've written a small
> > > one that should do the trick.
> >
> > [...]
> >
> > > sage: sarrus(matrix)
> > > '[1 \\cdot 0 \\cdot 1 + 1 \\cdot (-1) \\cdot (-1) + 1 \\cdot
> > > 1 \\cdot 0] - [1 \\cdot 0 \\cdot (-1) + 1 \\cdot 1 \\cdot 1
> > > + 1 \\cdot (-1) \ \cdot 0]'
> > > sage: print sarrus(matrix)
> > > [1 \cdot 0 \cdot 1 + 1 \cdot (-1) \cdot (-1) + 1 \cdot 1
> > > \cdot 0] - [1 \cdot 0 \cdot (-1) + 1 \cdot 1 \cdot 1 + 1
> > > \cdot (-1) \cdot 0]
> > >
> > > Does that answer your problem ?
> >
> > Thank you for the code (it's more elegant than my first try :)
> > ). It doesn't work too, because the problem is that sagetex is
> > putting the string in some kind of (typewriter-)enviroment.
> > After some experimentation i found a possible solution is to
> > replace "\cdot" with "$\cdot$". It doesn't look nice, but
> > better than before.
> >
> > Georg
> >
> > > On 5 mai, 11:28, "Dr. Georg Damm" <georg.d...@web.de> wrote:
> > > > Hi all,
> > > >
> > > > i've written a function to explain the rule of sarrus. Is
> > > > there a possibility to return latex code insted of a text?
> > > > I'd like to use something like $\sage{sarrus(A)}$ in
> > > > sagetex.
> > > >
> > > > Thanks a lot,
> > > >
> > > > Georg
> > > >
> > > > P.S.: I expirimented with JSMathExpr from sage.misc.latex,
> > > > but i couldn't improve the output.
> > > >
> > > > def sarrus(A):
> > > > res=""
> > > > for i in range(3):
> > > >
> > > > if (A[0,i]>=0):
> > > > res+="+"+latex(A[0,i])
> > > > else:
> > > > res+="+("+latex(A[0,i])+")"
> > > > if (A[1,(i+1)%3]>=0):
> > > > res+="*"+latex(A[1,(i+1)%3])
> > > > else:
> > > > res+="*("+latex(A[1,(i+1)%3])+")"
> > > > if (A[2,(i+2)%3]>=0):
> > > > res+="*"+latex(A[2,(i+2)%3])
> > > > else:
> > > > res+="*("+latex(A[2,(i+2)%3])+")"
> > > >
> > > > for i in range(2,5):
> > > > if (A[0,i%3]>=0):
> > > > res+="-"+latex(A[0,i%3])
> > > > else:
> > > > res+="-("+latex(A[0,i%3])+")"
> > > > if (A[1,(i-1)%3] >= 0):
> > > > res+="*"+latex(A[1,(i-1)%3])
> > > > else:
> > > > res+="*("+latex(A[1,(i-1)%3])+")"
> > > > if (A[2,(i-2)%3]>=0):
> > > > res+="*"+latex(A[2,(i-2)%3])
> > > > else:
> > > > res+="*("+latex(A[2,(i-2)%3])+")"
> > > > return res
> > > >
> > > > --
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> >
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