CODEWITHSUNDEEP
listfunctionargumentsmaxima
Gael Lorieul
Gael Lorieul

Reputation: 3246

maxima: calling function with list as argument

I can do this :

(%i1) myFunc(x) := x^2 + 1;
      myList : [1,2,3];
      myFunc(myList);

(%o1) myFunc(x):=x^2+1
(%o2) [1,2,3]
(%o3) [2,5,10]

and this as well :

(%i1) kill(all);
      load("pdiff");
      myFunc(x) := ratdisrep(taylor(diff(q('dst),'dst,x),'dst,0,5));
      myFunc(1);
      myFunc(2);
      myFunc(3);
(%o1) myFunc(x):=ratdisrep(taylor(diff(q('dst),'dst,x),'dst,0,5))
(%o2) [1,2,3]
(%o3) (q[(6)](0)*dst^5)/120+(q[(5)](0)*dst^4)/24+(q[(4)](0)*dst^3)/6+(q[(3)](0)*dst^2)/2+q[(2)](0)*dst+q[(1)](0)
(%o4) (q[(7)](0)*dst^5)/120+(q[(6)](0)*dst^4)/24+(q[(5)](0)*dst^3)/6+(q[(4)](0)*dst^2)/2+q[(3)](0)*dst+q[(2)](0)
(%o5) (q[(8)](0)*dst^5)/120+(q[(7)](0)*dst^4)/24+(q[(6)](0)*dst^3)/6+(q[(5)](0)*dst^2)/2+q[(4)](0)*dst+q[(3)](0)

but I can't do that :

(%i1) kill(all);
      load("pdiff");
      myFunc(x) := ratdisrep(taylor(diff(q('dst),'dst,x),'dst,0,5));
      myList : [1,2,3];
      myFunc(myList);

(%o1) myFunc(x):=ratdisrep(taylor(diff(q('dst),'dst,x),'dst,0,5))
(%o2) [1,2,3]
declare: argument must be a symbol; found "d"
 -- an error. To debug this try: debugmode(true);

Why does that happen, and how could I make my way around ?

Thanks in advance !

Upvotes: 1

Views: 306

Answers (1)

Robert Dodier
Robert Dodier

Reputation: 17576

I don't know where the error about declare is coming from -- I don't find any calls to declare in pdiff.lisp. When I copy your second example, instead of an error, I get: 'diff(q(dst),dst,[1,2,3]) which is to be expected, I think.

I guess you want to make a list with the output of myFunc for each element of myList. My advice is to simply map myFunc over myList. Some functions map over lists automatically; that is a convenience feature, not all functions have it. Here's what I get in this case:

(%i1) display2d : false $
(%i2) load ("pdiff") $
(%i3) myFunc(x) := ratdisrep(taylor(diff(q('dst),'dst,x),'dst,0,5)) $
(%i4) myList : [1,2,3] $
(%i5) map (myFunc, myList);
(%o5) [((pderivop(q,6))(0)*dst^5)/120+((pderivop(q,5))(0)*dst^4)/24
                                     +((pderivop(q,4))(0)*dst^3)/6
                                     +((pderivop(q,3))(0)*dst^2)/2
                                     +(pderivop(q,2))(0)*dst
                                     +(pderivop(q,1))(0),
       ((pderivop(q,7))(0)*dst^5)/120+((pderivop(q,6))(0)*dst^4)/24
                                     +((pderivop(q,5))(0)*dst^3)/6
                                     +((pderivop(q,4))(0)*dst^2)/2
                                     +(pderivop(q,3))(0)*dst
                                     +(pderivop(q,2))(0),
       ((pderivop(q,8))(0)*dst^5)/120+((pderivop(q,7))(0)*dst^4)/24
                                     +((pderivop(q,6))(0)*dst^3)/6
                                     +((pderivop(q,5))(0)*dst^2)/2
                                     +(pderivop(q,4))(0)*dst
                                     +(pderivop(q,3))(0)]

Upvotes: 2

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