MathAction #114 Map on Functions crash

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This problem does not occur on the NAG version:

  \begin{axiom}
  dom:=(INT->INT)
  g(f:dom):dom== x+->(f(x))^2
  p(x:INT):INT == x-1
  \end{axiom}

The next line crashes Axiom. (Here the crash is indicated by not showing the result for q which should be something like theMap(LAMBDA_ibs3ze_708.174) (from NAG version):

  \begin{axiom}
  q:= g p
  \end{axiom}

Below is the transcript for the NAG version:

G82322 (1) -> dom:= (INT->INT)   (1)  (Integer -> Integer)
                                                                 Type: Domain
G82322 (2) -> g(f:dom):dom== x+->(f(x))^2
   Function declaration g : (Integer -> Integer) -> (Integer -> Integer
      ) has been added to workspace.
                                                                   Type: Void
G82322 (3) -> p(x:INT):INT==x-1
   Function declaration p : Integer -> Integer has been added to 
      workspace.
                                                                   Type: Void
G82322 (4) -> q:= g p
   Compiling function p with type Integer -> Integer 
   Compiling function g with type (Integer -> Integer) -> (Integer -> 
      Integer)

+++ |*1;g;1;G82322| redefined

   (4)  theMap(LAMBDA_ibs3ze_708,174)
                                                   Type: (Integer -> Integer)
G82322 (5) -> q 3
   (5)  4
                                                        Type: PositiveInteger

property change --wyscc, Fri, 04 Mar 2005 04:37:59 -0600 reply

Name: #114 Maps on Function crash => #114 Map on Functions crash

Here is one way that works: Fri, 04 Mar 2005 05:18:25 -0600 reply

axiom

)clear all

   All user variables and function definitions have been cleared.

We can avoid the use of an anonymous function and use function composition to define the functional g as follows:

axiom

dom ==> INT -> INT

Type: Void

axiom

g(f:dom):dom ==
  function(x^2,sq,x)
  sq * f

   Function declaration g : (Integer -> Integer) -> (Integer -> Integer
      ) has been added to workspace.

Type: Void

axiom

p(x:INT):INT == x-1

   Function declaration p : Integer -> Integer has been added to 
      workspace.

Type: Void

axiom

q := g p

axiom

Compiling function p with type Integer -> Integer 
   There are 35 exposed and 24 unexposed library operations named * 
      having 2 argument(s) but none was determined to be applicable. 
      Use HyperDoc Browse, or issue
                                )display op *
      to learn more about the available operations. Perhaps 
      package-calling the operation or using coercions on the arguments
      will allow you to apply the operation.
   Cannot find a definition or applicable library operation named * 
      with argument type(s) 
                                Variable(sq)
                            (Integer -> Integer)

      Perhaps you should use "@" to indicate the required return type, 
      or "$" to specify which version of the function you need.
   FriCAS will attempt to step through and interpret the code.

axiom

Compiling function g with type (Integer -> Integer) -> (Integer -> 
      Integer) 
   Compiled code for g has been cleared.

axiom

Compiling function sq with type Integer -> Integer

$\label{eq1}\mbox{theMap (...)}$

(1)

Type: (Integer -> Integer)

axiom

q 3

$\label{eq2}4$

(2)

Type: PositiveInteger?

Using the SPAD compiler --Bill Page, Fri, 04 Mar 2005 07:03:34 -0600 reply

Take a look at FunctionalMapping? for an example of this sort thing written in SPAD.

anonymous function --wyscc, Fri, 04 Mar 2005 23:51:55 -0600 reply

Thanks to both contributions and guides to use composition. However, this is a bug still since the original code works under the NAG version. We should figure out why the open source version breaks down. Afterall, anonymous functions are convenience that the system should be able to handle by assigning intermediate variables automatically.

property change: Tue, 08 Mar 2005 04:54:41 -0600 reply
property change: Tue, 22 Mar 2005 20:12:54 -0600 replySeverity: serious => critical

property change --greg, Sat, 01 Apr 2006 10:37:11 -0600 reply

Status: open => pending (next release)

fixed in --patch-49 --greg, Wed, 19 Apr 2006 12:34:59 -0500 reply

Status: pending (next release) => closed

Subject: Be Bold !!

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