Awhile back Rob Hodgkinson brought my attention to the
forward difference function.
] a=:(i.10)^3
0 1 8 27 64 125 216 343 512 729
diff=: }. - }:
diff a
1 7 19 37 61 91 127 169 217
diff^:3 a
6 6 6 6 6 6 6
I want to write a verb that uses the left parameter to
identify the order of forward difference, and the
right for the data.
The problem I encounter seems to turn on my need to
process a monadic verb within a dyadic context. Here
are some failed incremental efforts:
diff1=: }. - }:^:1
diff1 a
1 7 19 37 61 91 127 169 217
NB. Success to that small degree. But:
diffx=: }. - }:^:[
1 diffx a
|domain error: diffx
| 1 diffx a
NB. Explicit definition also fails:
diffxe=: 3 : '}. - }:^:x y'
1 diffxe a
|domain error: diffxe
| 1 diffxe a
How do I keep the left parameter from forcing a dyadic
interpretation of (}. - }:)? Or, is that not the
problem?
--
Tracy B. Harms
The advantages of executability and universality
found in programming languages can be effectively
combined, in a single coherent language, with the
advantages offered by mathematical notation.
Kenneth E. Iverson
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