This does the trick in J904 - perhaps there's a better way of emulating
D.(i.3) ...
load'plot'
load'~addons/math/calculus/calculus.ijs'
u =. ^@-@-:@*:"0
u1=. (u deriv_jcalculus_ 1)
u2=. (u1 deriv_jcalculus_ 1)
$>(u;u1;u2)10%~50-~i.101
3 101
plot >(u;u1;u2)10%~50-~i.101
Mik
But... as I've just discovered, the equivalent function expressed as
^@-@-:@*:
does yield a "smooth" curve for the 2nd differential, so presumably
there's a
different need to do or level of approximation with ^&2 compared to *:
There is a remark
Generating higher-order partial derivative
Well, I've discovered that this works ok in J807:
plot|:^@-@-:@*:"0 D.(i.3)10%~50-~i.101 NB. replace ^&2 by *: (!)
I wasn't sure that you needed "0 so tried
plot|:^@-@-:@*: D.(i.3)10%~50-~i.101
but that suffers the same problem with the 2nd derivative!
We're supposed to use d
What is the equivalent of the program:
* plot|:^@-@-:@^&2"0 D.(i.3)10%~50-~i.101*
for users of J version 9.04g, where the D. primitive has been removed?
Where is the doc on the new calculus functions?
Skip
Skip Cave
Cave Consulting LLC
On Thu, Nov 24, 2022 at 12:01 PM 'Bo Jacoby' via Programmi
Presumably you're working with an older version of J, like J807. (J9
tossed the D. conjunction and requires we use the math/calculus
library manually.)
Anyways, if you increase the size of the plot, you'll see that the
display artifact you're looking at is a consequence of discretization
-- the pl
