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 Submitted by : (unknown) at: 2007-11-17T22:23:18-08:00 (12 years ago) Name : Axiom Version : default friCAS-20090114 Axiom-20050901 OpenAxiom-20091012 OpenAxiom-20110220 OpenAxiom-Release-141 Category : Axiom Aldor Interface Axiom Compiler Axiom Library Axiom Interpreter Axiom Documentation Axiom User Interface building Axiom from source lisp system MathAction Doyen CD Reduce Axiom on Windows Axiom on Linux Severity : critical serious normal minor wishlist Status : open closed rejected not reproducible fix proposed fixed somewhere duplicate need more info Optional subject :   Optional comment :

axiom
)set message autoload on

axiom
for i in 1..1 repeat print(sin(i) :: Complex Float)
sin(1)
Type: Void

Note that neither Float nor Complex is loaded in (1), only in (2). More surprisingly, UniversalSegment? is also not loaded in (1). (it does not matter if the segment is 1..1 or 1..3).

axiom
for i in 1..3 repeat print(sin(i)::Complex Float)
sin(1)
sin(2)
sin(3)
Type: Void
axiom
for i in 1..3 repeat print(a:=sin(i)::Complex Float)
0.8414709848 0789650665
0.9092974268 256816954
0.1411200080 598672221
Type: Void

Hmm, we need to understand this a bit more:

axiom
for i in 1..1 repeat print(a:=sin(i)::Complex Float)
0.8414709848 0789650665
Type: Void
axiom
for i in 1..1 repeat print(a:=(sin(i)::Complex Float))
0.8414709848 0789650665
Type: Void

all give:

  0.8414709848 0789650665


At least that is a work-around.

But

axiom
for i in 1..1 repeat print((a:=sin(i))::Complex Float)
0.8414709848 0789650665
Type: Void
axiom
for i in 1..1 repeat (a:=sin(i); print(a::Complex Float))
sin(1)
Type: Void

Gives:

sin(1)

print is from PrintPackage?, which calls print from OutputForm?, which calls mathprint$Lisp but the problem lies in print inside a loop (any type, not just a for-loop). The problem seems to be an interpreter problem in parsing. This is confirmed partly by the following transcript. When trying to code this as a package for the compiler, it is not easy to figure out the sequence of functions to use to coerce sin(i) from EXPR INT to Complex Float. I finally found one way, but it may not be what the interpreter is doing:  --%Printest )abbrev package PRINTEST Printest Printest: T==C where EXPR ==> Expression INT ==> Integer CF ==> Complex Float T == with foo:PositiveInteger->Void C == add import EXPR INT foo(k)== for i in 1..k repeat a:=sin(i::INT::Float::CF::EXPR CF)$(EXPR CF)
print(retract(a)$(EXPR CF)@CF::OutputForm)  Of course it makes no difference whether a:= is eliminated or not. And this works correctly. So my tentative conclusion is that the interpreter is "lazy" in (1) to try to figure out this rather involved coercion sequence (Hey, I got it to EXPR INT and I have no idea how to go further to Complex Float, I think it is good enough ...:-), but in (2), it is somehow forced to work harder (Now you want to save the result and I have to type the variable a, ok, ...). Is it a bug? Don't know. There are limitations to the interpreter. Tim: Do you know if there is a system limitation on the level of coercion the interpreter will try before quitting? Can this be reset? This example shows why a large percent of time (my low estimate is 70% and my high is 90%) writing compiled code is spent on coercion. Now, there is still the question: why does this happen only inside a loop? Can one tell more from the way the libraries are loaded (see attached print.out)? Notice in print.out, even after foo(3) is executed, (2) still needs to load another bunch of libraries. Why? William The comments below turned out to be in error: axiom for i in 1..1 repeat print(sqrt(i) :: Complex Float) 1 Type: Void axiom for i in 1..1 repeat print(exp(i) :: Complex Float) %e Type: Void axiom for i in 1..1 repeat print(log(i) :: Complex Float) 0 Type: Void axiom for i in 1..1 repeat print(atan(i) :: Complex Float) %pi --- 4 Type: Void I'd say that it's a bug. A workaround (not a fix...) is to say axiom for i in 1..1 repeat print(sqrt(i) @ Complex Float) 1.0 Type: Void It is quite clear that Axioms behaviour will be the same for all operators (defined in op.spad). Tracing the call with axiom )set message bottom on for i in 1..3 repeat print((sin(i))::Complex Float) Function Selection for sin Arguments: PI  signature: EXPR(INT) -> EXPR(INT) implemented: slot$\$ from EXPR(INT)
Function Selection for print
Arguments: COMPLEX(FLOAT)
  signature:   OUTFORM -> VOID
implemented: slot (Void)(OutputForm) from PRINT
sin(1)
sin(2)
sin(3)
Type: Void

which looks quite strange: Axiom is looking for a function print with argument of type Complex Float, but the thing it prints is not of this type...

Category: Axiom Mathematics => Axiom Interpreter Status: closed => open

the bug with sin is still open

Name: #29 for i in 1..1 repeatprint(sin(i) :: Complex Float) => #29 for i in 1..1 repeat print(sin(i) :: Complex Float)

Status: open => closed

 Subject:   Be Bold !! ( 15 subscribers )