Re: [Scilab-users] Strange behaviour of prod on rationals
Pierre, Thanks for your answer. However, I believe no involved computatins are required to get the correct result. The multiplication of the two polynomials from the denominators is straightforward, no need to solve any system, no risk of ill-conditioned or badly-scaled matrices. This must be another kind of problem. Regards, Federico Miyara On 17/03/2020 06:48, Perrichon wrote: Hello Federico I have met few months or years ago this problem when i was developping my « OPTSIM Solution » software to fix parameters of a PID for turbines (30 mw to 2 gw) in Nyquist and Bode Plans with hydraulic parameters site So I’ve seen instability of the denominator, witch damage calculus. I don ‘t remember what I’ve done to get a cool solution, but it has been a hard and severe problem with syslin, tf2ss and ss2tf instructions Sincerely Pierre P. *De :*users *De la part de* Federico Miyara *Envoyé :* mardi 17 mars 2020 10:31 *À :* Users mailing list for Scilab *Objet :* [Scilab-users] Strange behaviour of prod on rationals Dear all, Look at this code (the coefficients are actually the result of pevious calculations): NUM = [5.858D-09 + 2.011D-08*%s + 4.884D-08*%s^2 ... 5.858D-09 + 8.796D-10*%s + 7.028D-10*%s^2] DEN = [0.1199597 + 7.2765093*%s + %s^2 ... 8.336136 + 7.0282601*%s + %s^2] q = NUM./DEN Running it yields 5.858D-09 +2.011D-08s +4.884D-08s² 5.858D-09 +8.796D-10s +7.028D-10s² -- -- 0.1199597 +7.2765093s +s² 8.336136 +7.0282601s +s² This is, correctly, a two-component rational vector with the expected numerators and denominators. Now let's evaluate q = prod(NUM./DEN) The prod documantation sys that the argument may be "an array of reals, complex, booleans, polynomials or rational fractions". It should provide the rational obtained by multiplying the twonumrators and the two denominators. However, we get 3.432D-17 +1.230D-16s +3.079D-16s² +5.709D-17s³ +3.432D-17s⁴ 1 The numeratoris right, but the expected denominator has been just replaced by 1 However, rewriting the command as prod(NUM)/prod(DEN) we get the expected result: 3.432D-17 +1.230D-16s +3.079D-16s² +5.709D-17s³ +3.432D-17s⁴ 1.004 +61.501079s +59.597296s² +14.304769s³ +s⁴ This is quite strange! Now we repeat with simpler polynomials: NUM = [1-%s 2-%s] DEN = [1+%s 2+%s] q = NUM./DEN We get 1 -s 2 -s 1 +s 2 +s Now evaluate prod(NUM./DEN) The result is the expected one! 2 -3s +s² - 2 +3s +s² The behavior seems to depend on the type of polynomials. Is this a bug or there is something I'm not interpreting correctly? Regards, Federico Miyara ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] ?==?utf-8?q? Bug report etiquette : memory leaks in graphics
Hello, Following a private discussion with Samuel, I submitted a bug report on a memory leak in Matplot(): http://bugzilla.scilab.org/show_bug.cgi?id=16377 Cheers, Antoine Le Mardi, Mars 17, 2020 15:28 CET, "Antoine Monmayrant" a écrit: > Hi all, > > I know that it's usually bad practice to duplicate an already existing bug. > But it's also good practice to make one report per specific bug. > I've just waisted two days on a nasty memory leak when plotting/clearing a > graph in a loop (50 iterations were enough to kill scilab). > Looking at reports of bugzilla, I see plethora of memory leak bugs for > graphics (eg #14310, #14508, #14977 to name just a few) that are most > probably all related. > > Should I report a new bug or comment on these ones, being slightly off topic? > > Antoine > > ___ > users mailing list > users@lists.scilab.org > http://lists.scilab.org/mailman/listinfo/users > ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
[Scilab-users] Bug report etiquette : memory leaks in graphics
Hi all, I know that it's usually bad practice to duplicate an already existing bug. But it's also good practice to make one report per specific bug. I've just waisted two days on a nasty memory leak when plotting/clearing a graph in a loop (50 iterations were enough to kill scilab). Looking at reports of bugzilla, I see plethora of memory leak bugs for graphics (eg #14310, #14508, #14977 to name just a few) that are most probably all related. Should I report a new bug or comment on these ones, being slightly off topic? Antoine ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] Strange behaviour of prod on rationals
Here are examples of my process in Open loop (FTBO) or Close loop (FTBF)
Depending of managemat, D can have s14 …
De : Perrichon
Envoyé : mardi 17 mars 2020 10:49
À : 'Users mailing list for Scilab'
Objet : RE: [Scilab-users] Strange behaviour of prod on rationals
Hello Federico
I have met few months or years ago this problem when i was developping my «
OPTSIM Solution » software to fix parameters of a PID for turbines (30 mw to 2
gw) in Nyquist and Bode Plans with hydraulic parameters site
So I’ve seen instability of the denominator, witch damage calculus.
I don ‘t remember what I’ve done to get a cool solution, but it has been a
hard and severe problem with syslin, tf2ss and ss2tf instructions
Sincerely
Pierre P.
De : users mailto:users-boun...@lists.scilab.org> > De la part de Federico Miyara
Envoyé : mardi 17 mars 2020 10:31
À : Users mailing list for Scilab mailto:users@lists.scilab.org> >
Objet : [Scilab-users] Strange behaviour of prod on rationals
Dear all,
Look at this code (the coefficients are actually the result of pevious
calculations):
NUM = [5.858D-09 + 2.011D-08*%s + 4.884D-08*%s^2 ...
5.858D-09 + 8.796D-10*%s + 7.028D-10*%s^2]
DEN = [0.1199597 + 7.2765093*%s + %s^2 ...
8.336136 + 7.0282601*%s + %s^2]
q = NUM./DEN
Running it yields
5.858D-09 +2.011D-08s +4.884D-08s² 5.858D-09 +8.796D-10s +7.028D-10s²
-- --
0.1199597 +7.2765093s +s²8.336136 +7.0282601s +s²
This is, correctly, a two-component rational vector with the expected
numerators and denominators.
Now let's evaluate
q = prod(NUM./DEN)
The prod documantation sys that the argument may be "an array of reals,
complex, booleans, polynomials or rational fractions". It should provide the
rational obtained by multiplying the twonumrators and the two denominators.
However, we get
3.432D-17 +1.230D-16s +3.079D-16s² +5.709D-17s³ +3.432D-17s⁴
1
The numeratoris right, but the expected denominator has been just replaced by 1
However, rewriting the command as
prod(NUM)/prod(DEN)
we get the expected result:
3.432D-17 +1.230D-16s +3.079D-16s² +5.709D-17s³ +3.432D-17s⁴
1.004 +61.501079s +59.597296s² +14.304769s³ +s⁴
This is quite strange!
Now we repeat with simpler polynomials:
NUM = [1-%s 2-%s]
DEN = [1+%s 2+%s]
q = NUM./DEN
We get
1 -s 2 -s
1 +s 2 +s
Now evaluate
prod(NUM./DEN)
The result is the expected one!
2 -3s +s²
-
2 +3s +s²
The behavior seems to depend on the type of polynomials.
Is this a bug or there is something I'm not interpreting correctly?
Regards,
Federico Miyara
___
users mailing list
users@lists.scilab.org
http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] Strange behaviour of prod on rationals
Hello Federico
I have met few months or years ago this problem when i was developping my «
OPTSIM Solution » software to fix parameters of a PID for turbines (30 mw to 2
gw) in Nyquist and Bode Plans with hydraulic parameters site
So I’ve seen instability of the denominator, witch damage calculus.
I don ‘t remember what I’ve done to get a cool solution, but it has been a
hard and severe problem with syslin, tf2ss and ss2tf instructions
Sincerely
Pierre P.
De : users De la part de Federico Miyara
Envoyé : mardi 17 mars 2020 10:31
À : Users mailing list for Scilab
Objet : [Scilab-users] Strange behaviour of prod on rationals
Dear all,
Look at this code (the coefficients are actually the result of pevious
calculations):
NUM = [5.858D-09 + 2.011D-08*%s + 4.884D-08*%s^2 ...
5.858D-09 + 8.796D-10*%s + 7.028D-10*%s^2]
DEN = [0.1199597 + 7.2765093*%s + %s^2 ...
8.336136 + 7.0282601*%s + %s^2]
q = NUM./DEN
Running it yields
5.858D-09 +2.011D-08s +4.884D-08s² 5.858D-09 +8.796D-10s +7.028D-10s²
-- --
0.1199597 +7.2765093s +s²8.336136 +7.0282601s +s²
This is, correctly, a two-component rational vector with the expected
numerators and denominators.
Now let's evaluate
q = prod(NUM./DEN)
The prod documantation sys that the argument may be "an array of reals,
complex, booleans, polynomials or rational fractions". It should provide the
rational obtained by multiplying the twonumrators and the two denominators.
However, we get
3.432D-17 +1.230D-16s +3.079D-16s² +5.709D-17s³ +3.432D-17s⁴
1
The numeratoris right, but the expected denominator has been just replaced by 1
However, rewriting the command as
prod(NUM)/prod(DEN)
we get the expected result:
3.432D-17 +1.230D-16s +3.079D-16s² +5.709D-17s³ +3.432D-17s⁴
1.004 +61.501079s +59.597296s² +14.304769s³ +s⁴
This is quite strange!
Now we repeat with simpler polynomials:
NUM = [1-%s 2-%s]
DEN = [1+%s 2+%s]
q = NUM./DEN
We get
1 -s 2 -s
1 +s 2 +s
Now evaluate
prod(NUM./DEN)
The result is the expected one!
2 -3s +s²
-
2 +3s +s²
The behavior seems to depend on the type of polynomials.
Is this a bug or there is something I'm not interpreting correctly?
Regards,
Federico Miyara
___
users mailing list
users@lists.scilab.org
http://lists.scilab.org/mailman/listinfo/users
[Scilab-users] Strange behaviour of prod on rationals
Dear all, Look at this code (the coefficients are actually the result of pevious calculations): NUM = [5.858D-09 + 2.011D-08*%s + 4.884D-08*%s^2 ... 5.858D-09 + 8.796D-10*%s + 7.028D-10*%s^2] DEN = [0.1199597 + 7.2765093*%s + %s^2 ... 8.336136 + 7.0282601*%s + %s^2] q = NUM./DEN Running it yields 5.858D-09 +2.011D-08s +4.884D-08s² 5.858D-09 +8.796D-10s +7.028D-10s² -- -- 0.1199597 +7.2765093s +s² 8.336136 +7.0282601s +s² This is, correctly, a two-component rational vector with the expected numerators and denominators. Now let's evaluate q = prod(NUM./DEN) The prod documantation sys that the argument may be "an array of reals, complex, booleans, polynomials or rational fractions". It should provide the rational obtained by multiplying the twonumrators and the two denominators. However, we get 3.432D-17 +1.230D-16s +3.079D-16s² +5.709D-17s³ +3.432D-17s⁴ 1 The numeratoris right, but the expected denominator has been just replaced by 1 However, rewriting the command as prod(NUM)/prod(DEN) we get the expected result: 3.432D-17 +1.230D-16s +3.079D-16s² +5.709D-17s³ +3.432D-17s⁴ 1.004 +61.501079s +59.597296s² +14.304769s³ +s⁴ This is quite strange! Now we repeat with simpler polynomials: NUM = [1-%s 2-%s] DEN = [1+%s 2+%s] q = NUM./DEN We get 1 -s 2 -s 1 +s 2 +s Now evaluate prod(NUM./DEN) The result is the expected one! 2 -3s +s² - 2 +3s +s² The behavior seems to depend on the type of polynomials. Is this a bug or there is something I'm not interpreting correctly? Regards, Federico Miyara ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
