Type control

[salvomic]

hi,
why the IF ELSE control for type control in this program works, but it doesn't works in a non CAS program?

Code:


#cas
multinom(args):=
// multinom(n,{list k_i})
BEGIN
local n, k, argv,argc;
argv:=[args];
argc:=size(argv);
IF argc !=2 THEN
return "Input: integer n, {list k}"; 
ELSE
n:=argv(1);
k:=argv(2);
IF (type(k) != DOM_LIST) THEN return "2nd argument must be a list"; ELSE
 n:= ip(n); k:= ip(k);
 return  n!/∏LIST(k!);
END; // if inner

END; // if out

END;
#end

If I try

Code:


EXPORT Multinomd(n,k,p)
BEGIN
...
IF ((type(k) != DOM_LIST) OR (type(k) != DOM_LIST)) THEN return "2nd and 3rd argument must be a list"; ELSE
...
END;

type(k) control won't be executed, here.
If I use

Code:


EXPORT Multinomd(args)
BEGIN
local argv,argc;
argv:=[args];
argc:=size(argv);
IF argc !=3 THEN
return "Input: integer n, {list k}, {list p}"; 
ELSE
n:=argv(1);
k:=argv(2);
p:=argv(3);
IF ((type(k) != DOM_LIST) OR (type(k) != DOM_LIST)) THEN return "2nd and 3rd argument must be a list"; ELSE
...

END;

the program doesn't work at all, giving "Error: Bad argument value" (I think the logical error is in "argv:= [args]"...: why? this approach works well in the #cas / #end version...

I must control in a 3 arguments if 2nd and 3rd are lists, otherwise return to the user the message that they *must* be lists.

Thank you!

[Han]

In CAS, typing: a,b,c,d creates a list. That's just how the CAS environment parses a sequence of objects separated by a comma. So in a CAS program,

f(a,b,c,d)

can be considered as a function that takes 4 separate arguments named a,b,c, and d, or f can be considered as a function that takes a single argument: a list consisting of 4 items.

[salvomic]

ok, I'm working about this code:

Code:


EXPORT Multinomd(n, k, p)
// Multinomial distribution (n>0,{list k_i}, {list p_i})
BEGIN

IF ((type(k) ≠ 6) OR (type(p) ≠ 6)) THEN 
return "2nd and 3th argument must be a list"; ELSE
n:= ip(n);
return  (n!/ΠLIST(k!))*ΠLIST(p^k);
END; // if 
END;

for now it' almost ok, but I must also control the number of parameters, to avoid the "error: Bad Argument value" if they are less or more than 3.
(in CAS version I could use "IF argc !=3 ...)

Other: why in CAS I could write
IF ((type(k) != DOM_LIST) OR (type(p) != DOM_LIST)) THEN

and in non-CAS it doesn't works?
I must use
IF ((type(k) ≠ 6) OR (type(p) ≠ 6)) THEN
instead?

[Joe Horn]

(02-22-2015 04:46 PM)salvomic Wrote:  Other: why in CAS I could write
IF ((type(k) != DOM_LIST) OR (type(p) != DOM_LIST)) THEN

and in non-CAS it doesn't works?
I must use
IF ((type(k) ≠ 6) OR (type(p) ≠ 6)) THEN
instead?

The "type" command is different from the "TYPE" command (see their respective help screens in the Toolbox Catalog). Both work correctly in CAS, but Home's parser interprets "type" as "TYPE", which causes the following unexpectedly different results:

CAS: TYPE( {1,2,3} ) --> 6
CAS: Type( {1,2,3} ) --> 6
CAS: type( {1,2,3} ) --> DOM_LIST
CAS: type( {1,2,3} )+0 --> 7

Home: TYPE( {1,2,3} ) --> 6
Home: Type( {1,2,3} ) --> 6
Home: type( {1,2,3} ) --> 6
Home: type( {1,2,3} )+0 --> 6

[salvomic]

(02-22-2015 08:47 PM)Joe Horn Wrote:  The "type" command is different from the "TYPE" command (see their respective help screens in the Toolbox Catalog). Both work correctly in CAS, but Home's parser interprets "type" as "TYPE",...

ah, you are right, I didn't remember...
thank you.

Then, there is also difference with ≠ and !=; CAS accepts the second one, Home don't.

[Joe Horn]

(02-22-2015 08:52 PM)salvomic Wrote:  ... there is also difference with ≠ and !=; CAS accepts the second one, Home don't.

A substitute for ≠ that works in both Home and CAS is <>. Handy when using your computer keyboard instead of Prime's keyboard (on which ≠ is available in just three keystrokes: Shift 6 5).

[salvomic]

(02-23-2015 04:17 AM)Joe Horn Wrote:  A substitute for ≠ that works in both Home and CAS is <>. Handy when using your computer keyboard instead of Prime's keyboard (on which ≠ is available in just three keystrokes: Shift 6 5).

ok, thank you for advise.
Yes, in Windows it's a bit tricky to insert special characters. In Mac OS ≠ it would be only ALT 0.

Another symbol to know, writing for the Prime with PC keyboard is the -> that in the Prime is a single char: any hints?

[salvomic]

(02-22-2015 04:37 PM)Han Wrote:  In CAS, typing: a,b,c,d creates a list. That's just how the CAS environment parses a sequence of objects separated by a comma. So in a CAS program,

f(a,b,c,d)

can be considered as a function that takes 4 separate arguments named a,b,c, and d, or f can be considered as a function that takes a single argument: a list consisting of 4 items.

Han,
if I input [a,b], there is a way (in CAS) to tell the program that this input should be a matrix or vector and *not* a list? or other trick to do that?
In my program for Wronskian I would like threat only input like [x, x^2, ...] not also {...} or x,x^2,... if it's possible.

Thank you!

[toml_12953]

(02-23-2015 08:31 AM)salvomic Wrote:  

(02-23-2015 04:17 AM)Joe Horn Wrote:  A substitute for ≠ that works in both Home and CAS is <>. Handy when using your computer keyboard instead of Prime's keyboard (on which ≠ is available in just three keystrokes: Shift 6 5).

ok, thank you for advise.
Yes, in Windows it's a bit tricky to insert special characters. In Mac OS ≠ it would be only ALT 0.

Another symbol to know, writing for the Prime with PC keyboard is the -> that in the Prime is a single char: any hints?

You could try → Which in Windows is U+2192 or ► which is U+25BA. To type thise in, Hold down the Alt key, the numeric pad + key and type the four-digit hex value. Now release the Alt key. In order for this to work, you have to use RegEdit. Navigate to HKEY_Current_User/Control Panel/Input Method, and set EnableHexNumpad to "1" or add it as a text value if it's not already there.

[salvomic]

(02-23-2015 04:52 PM)toml_12953 Wrote:  You could try → Which in Windows is U+2192 or ► which is U+25BA. To type thise in, Hold down the Alt key, the numeric pad + key and type the four-digit hex value. Now release the Alt key. In order for this to work, you have to use RegEdit. Navigate to HKEY_Current_User/Control Panel/Input Method, and set EnableHexNumpad to "1" or add it as a text value if it's not already there.

thank you!
I'll try soon.

Have a nice day

[Han]

(02-23-2015 04:51 PM)salvomic Wrote:  

(02-22-2015 04:37 PM)Han Wrote:  In CAS, typing: a,b,c,d creates a list. That's just how the CAS environment parses a sequence of objects separated by a comma. So in a CAS program,

f(a,b,c,d)

can be considered as a function that takes 4 separate arguments named a,b,c, and d, or f can be considered as a function that takes a single argument: a list consisting of 4 items.

Han,
if I input [a,b], there is a way (in CAS) to tell the program that this input should be a matrix or vector and *not* a list? or other trick to do that?
In my program for Wronskian I would like threat only input like [x, x^2, ...] not also {...} or x,x^2,... if it's possible.

Thank you!

If you're trying to do some sort of dynamic input, then your function should be only defined as a function of a single variable (a list). For example:

Code:

#cas
myfunc(v):=
BEGIN
  local s;
  s:=SIZE(v);
  IF s>4 THEN RETURN("Too many arguments"); END;

  CASE
    IF s==1 THEN
      IF TYPE(v(1))<>4 THEN RETURN("First argument must be vector"); END;
      // and so on...
    END;

    IF s==2 THEN
      // etc.
    END;
  END;

END;

Note that in CAS, TYPE() and type() are two different functions. In non-CAS programs, there is only one "type" command -- the non-CAS one. In non-CAS programs, whether you use TYPE() or type(), either one will be interpreted as TYPE(). CASE vs case, RETURN() vs return, are among many differences you will have to learn.

[salvomic]

(02-23-2015 05:10 PM)Han Wrote:  Note that in CAS, TYPE() and type() are two different functions. In non-CAS programs, there is only one "type" command -- the non-CAS one.
RETURN() vs return,
... are among many differences you will have to learn.

yes, I've still many differences to learn

ok, I'm doing about in that mode.
I've now two little issues to solve:
1. in my specific program the list is type [x, x, x], so I cannot control for v(1), but I must control for the whole v, and it is seen always as list, so the control for <>4 doesn't match (in that program the list is always seen as type 6)...
2. how to avoid (if it's possible) to input nameprogram without () that in my case give a strange (flist)→LOCAL[[mat s j k d ... error?

thanks again!
your help is very precious for me ;-)

[Han]

(02-23-2015 05:40 PM)salvomic Wrote:  1. in my specific program the list is type [x, x, x], so I cannot control for v(1), but I must control for the whole v, and it is seen always as list, so the control for <>4 doesn't match (in that program the list is always seen as type 6)...
2. how to avoid (if it's possible) to input nameprogram without () that in my case give a strange (flist)→LOCAL[[mat s j k d ... error?

1. My example was simply that -- an example. It was not a direct answer to your specific case. You would need to modify the example to make it fit your own needs. I don't understand your need to encase args inside [ and ]. The input args is already a CAS list.

Just try this:

Code:

#cas
myexample(args):=
  local s;
  s:=SIZE(args);
  IF s==0 THEN RETURN("No args given"); END;
  RETURN(args(s));
END;
#end

This will always return the last item in the argument list. The more general case (code below allows myprog(real, list) or myprog(real, list, list):

Code:

#cas
myprog(args):=
BEGIN
  local s:=SIZE(args);
  IF s==2 THEN
    IF TYPE(args(1)) OR TYPE(args(2))<>6 THEN
      RETURN("Usage: myprog(real, list)");
    ELSE
      // your code; use a RETURN()
    END;
  END;

  IF s==3 THEN
    IF TYPE(args(1)) OR TYPE(args(2))<>6 OR TYPE(args(3))<>6 THEN
      RETURN("Usage: myprog(real, list, list)");
    ELSE
      // your code; use a RETURN()
    END;
  END

  RETURN("Invalid input");

END;
#end

This doesn't work for non-CAS programs because the Home environment doesn't parse comma-separated entries the same way. The non-CAS programs must either be programmed to take an explicit list of inputs or you must use a CAS program. That is, HOMEPROG(list) where list is an actual list would work for non-CAS programs. However, a CAS program can simply use CASPROG(args).

2. A CAS program is essentially a function, much like f is a function when declared as f(x):=x^2. When you type f, you will see (x)->(x^2) as this is how the CAS represents functions. Thus, by simply typing the name of a function, you return its actual contents. There is no getting around this.

[salvomic]

(02-23-2015 07:18 PM)Han Wrote:  1. My example was simply that -- an example. It was not a direct answer to your specific case. You would need to modify the example to make it fit your own needs. I don't understand your need to encase args inside [ and ]. The input args is already a CAS list.

Yes, ok, it is already a CAS list. I thought that it was possible to handle a vector or matrix in different mode than with a list...
I was applying your advise to this program.

Quote:2. A CAS program is essentially a function, much like f is a function when declared as f(x):=x^2. When you type f, you will see (x)->(x^2) as this is how the CAS represents functions. Thus, by simply typing the name of a function, you return its actual contents. There is no getting around this.

ok, thank you also for this clear explanation. In the last version of Wronskian it would be the last heavy "error", I can also leave it: the rest works.

Thanks a lot, Han!

Salvo

[Joe Horn]

(02-23-2015 08:31 AM)salvomic Wrote:  Another symbol to know, writing for the Prime with PC keyboard is the -> that in the Prime is a single char: any hints?

In most Windows software, ALT+26 yields the "→" character. Press and hold down the ALT key, then type 26 on the numeric keypad, then release the ALT key. It works in Word, the Prime Connectivity Kit, and this forum.

Another helpful Windows shortcut: ALT+16 yields the "►" symbol, used for "sto" on Prime.

[Angus]

As I mentioned in an other thread I encoutered problem when using the arrow. Go to CAS and define a function foo1 and foo2 as foo:=(x)->x
Even on the hardware when using the arrow directly with Shift+9 you get an Error message. When typing '-' and '>' (from Shift+6) it works fine, but the arrow is visualized as the built in arrow.

Is there anything I am doing wrong?

[salvomic]

(02-23-2015 11:40 PM)Joe Horn Wrote:  

(02-23-2015 08:31 AM)salvomic Wrote:  Another symbol to know, writing for the Prime with PC keyboard is the -> that in the Prime is a single char: any hints?

In most Windows software, ALT+26 yields the "→" character. Press and hold down the ALT key, then type 26 on the numeric keypad, then release the ALT key. It works in Word, the Prime Connectivity Kit, and this forum.

Another helpful Windows shortcut: ALT+16 yields the "►" symbol, used for "sto" on Prime.

(02-24-2015 06:28 AM)Angus Wrote:  As I mentioned in an other thread I encoutered problem when using the arrow. Go to CAS and define a function foo1 and foo2 as foo:=(x)->x
Even on the hardware when using the arrow directly with Shift+9 you get an Error message. When typing '-' and '>' (from Shift+6) it works fine, but the arrow is visualized as the built in arrow.

Is there anything I am doing wrong?

thanks both!
I note this things for future reference

Salvo

[Joe Horn]

(02-24-2015 06:28 AM)Angus Wrote:  As I mentioned in an other thread I encoutered problem when using the arrow. Go to CAS and define a function foo1 and foo2 as foo:=(x)->x
Even on the hardware when using the arrow directly with Shift+9 you get an Error message. When typing '-' and '>' (from Shift+6) it works fine, but the arrow is visualized as the built in arrow.

Is there anything I am doing wrong?

It only looks like "→" when Textbook Display mode is turned on (different from Textbook Entry mode). If you turn off Textbook Display mode (Home Settings page 2), you'll see that it's really the two characters ->, not the single character →. So it's just a "pretty print" display fiction. Always type what it really is: "->".

[salvomic]

(02-23-2015 07:18 PM)Han Wrote:  Just try this:

Code:

#cas
myexample(args):=
  local s;
  s:=SIZE(args);
  IF s==0 THEN RETURN("No args given"); END;
  RETURN(args(s));
END;
#end

...
This doesn't work for non-CAS programs because the Home environment doesn't parse comma-separated entries the same way. The non-CAS programs must either be programmed to take an explicit list of inputs or you must use a CAS program. That is, HOMEPROG(list) where list is an actual list would work for non-CAS programs. ...

Han,
in some CAS program of mine it works well...

now I've a non CAS program, and this code doesn't work:

Code:


EXPORT myprog(a);
BEGIN
local s;
s:= SIZE(a);
IF (s==0 OR TYPE(a)<>0) THEN RETURN("Input a real number"); END;
...

with myprog (not correct, I know) I get the error "Bad argument count" and with myprog() I get "Error: Bad argument value"

So, there isn't any way to control that input?

Thank you

[Han]

(03-12-2015 09:59 AM)salvomic Wrote:  

(02-23-2015 07:18 PM)Han Wrote:  Just try this:

Code:

#cas
myexample(args):=
  local s;
  s:=SIZE(args);
  IF s==0 THEN RETURN("No args given"); END;
  RETURN(args(s));
END;
#end

...
This doesn't work for non-CAS programs because the Home environment doesn't parse comma-separated entries the same way. The non-CAS programs must either be programmed to take an explicit list of inputs or you must use a CAS program. That is, HOMEPROG(list) where list is an actual list would work for non-CAS programs. ...

Han,
in some CAS program of mine it works well...

now I've a non CAS program, and this code doesn't work:

Code:


EXPORT myprog(a);
BEGIN
local s;
s:= SIZE(a);
IF (s==0 OR TYPE(a)<>0) THEN RETURN("Input a real number"); END;
...

with myprog (not correct, I know) I get the error "Bad argument count" and with myprog() I get "Error: Bad argument value"

So, there isn't any way to control that input?

Thank you

Ensure there are no conflicts between the CAS version of myprog and the non-CAS version of myprog. In other words, name them differently to make sure that when you type myprog you aren't running the wrong program (since different programs can actually have the same name). As for the error (w/ respect to the second code block in your post), it is being generated much further inside your program. What you have posted there does not produce any errors.