A reasonable expectation. sslope_jcalculus_ provides an approximation
to the slope. A user could write a conjunction to use that if
deriv_jcalculus_ can't find a closed-form derivative.
But: #.&1 _1 _2&> opens its argument. Can there ever be a derivative of
a boxed argument?
Henry Rich
On 1/15/2021 10:48 PM, Devon McCormick wrote:
I guess I was expecting a numerical solution if a symbolic one is not found.
On Fri, Jan 15, 2021 at 10:05 PM Henry Rich <[email protected]> wrote:
What do you expect the derivative of #.&1 _1 _2&> to be?
I see that #.&1 _1 _2 has no derivative, but 1 _1 _2&p. does.
Deficiencies in math/calculus are not 'issues'. They are opportunities
for improvement by users.
Henry Rich
On 1/15/2021 9:37 PM, Devon McCormick wrote:
I tried to update chapter 23 of the "50 Shades of J" essay using the new
version of Newton's method from "
https://code.jsoftware.com/wiki/Essays/Newton%27s_Method"; but this
breaks
examples in "50 Shades", e.g.
f1=: #.&1 _1 _2&> NB. Function to use
Newton=: adverb : ']-u % (u deriv_jcalculus_ 1'
f1 Newton 1
|domain error: deriv_jcalculus_
| 13!:8(3)
|deriv_jcalculus_[:19]
Is this a known issue?
I've left my "fix" in as the existing code will also break in the current
version of J.
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