- labels: --> Lisp Core
f(n):=IF n = 0 THEN 1 ELSE 91919*gg(x^n+f(EV(n-
1,SIMP)))
simp:false;
Now calculate and display f(6)*f(6) (with the display
window fairly narrow, say 60 columns wide).
displa generates lines that are wider than the window,
which wrap around and make the display illegible
(especially the exponents).
I realize that unsimplified expressions are an unusual
case.... I ran across this problem during a debugging
session where I turned of SIMP to check something.
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user_id=501686
Another bit of simp / display strangeness:
simp : false;
matrix ([a, b], [c, d]);
Result is displayed as "matrix([a, b], [c, d])" (i.e.
without the ascii art). I wonder why unsimplified matrices
aren't displayed the same as simplified ones.
I think this problem is not restricted to unsimplified expressions. It is a general problem of the 2d-display.
This is the most simple example I have found to see the general problem.
We take a long numerator and a long denominator.
(%i1) num:a1+a2+a3+a4+a5+a6+a7+a8+a9;
(%o1) a9 + a8 + a7 + a6 + a5 + a4 + a3 + a2 + a1
(%i2) denom:b1+b2+b3+b4+b5+b6+b7+b8+b9;
(%o2) b9 + b8 + b7 + b6 + b5 + b4 + b3 + b2 + b1
We set linel to a small value 10.
(%i4) linel:10;
(%o4) 10
We display num/denom. This is a correct display.
(%i5) num/denom;
(%o5) (a9
+ a8 + a7
+ a6 + a5
+ a4 + a3
+ a2
+ a1)
/(b9 + b8
+ b7 + b6
+ b5 + b4
+ b3 + b2
+ b1)
We get the error when we multiply the denominator with a further constant. The last line is no longer broken up correctly:
(%i6) num/(x*denom);
(%o6) (a9
+ a8 + a7
+ a6 + a5
+ a4 + a3
+ a2
+ a1)
/((b9 + b8 + b7 + b6 + b5 + b4 + b3 + b2 + b1) x)
I had a look into the display routines. The additional constant x causes a nested expression which seems to confuse the highly recursive algorithm and the counting of space available for the expression. But I have not seen a way to correct this behaviour.
Remark: The display of unsimplified matrices is easy to correct. The 2d-display routines have a check for unsimplified matrices. This can be removed without problems.
Changing the title to reflect the issue.
Dieter Kaiser
Sorry, but I have mixed up this problem with the problem of bug report ID: 1954693. Since Maxima 5.15 we have two problems with the 2d-display. I have recognised this today, because I had a look at all Maxima versions from 5.9 to 5.20 to find the differences in 2d-display.
The problem of this bug report is present since Maxima 5.9, it is not a problem of a long denominator but of a long unsimplified expression. The problem is still present in Maxima 5.20post.
Reverting the change of the title.
Dieter Kaiser
Fixed in the function dimnary in the file displa.lisp with revision 18 Jul 2011.
Closing this bug report as fixed.
Dieter Kaiser
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