Ronan

Alternative Argument spelling in a proce...

Asked: Ronan 1172 Product: Maple 2023

February 09 2024

2 7

This is something I use a fair bit. I have procedures with alternative spelling options for the colours Red Green and Blue.
Have shown a single example copied from an overloaded procedure. It there a nicer way of handling this than what I am doing?
There is a section in help under "Procedure Parameter Declarations" on "Indexed Keyword Parameters" but I don't see how to use it here. These procedures are used inside a package.

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restart

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>	GeomClr:="Blue"; # can be "Blue", "blue", "B", "b" or; # "Green", "green", "G", "g" or; # "Red2, "red", "R", "r"; Prntmsg:="y" ; # or anything that is not"y"

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(1)

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spread:=proc(p0::{satisfies(s -> type(s, [algebraic $ 2])),'Vector[row]'(2, algebraic)},
              p1::{satisfies(s -> type(s, [algebraic $ 2])),'Vector[row]'(2, algebraic)},
              clr::`string`:= GeomClr,
              prnt::`string`:=Prntmsg)
           option overload;
           uses LinearAlgebra;
           #print(clr,p0,p1);
           if clr="b" or clr="B" or clr="blue" or clr="Blue" then
              if prnt="y" then
                print("Spread 2 [x,y] Points/Vectors wrt origin Blue");
              end if;
               return 1 - BilinearForm(p0, p1, conjugate = false)^2/(BilinearForm(p0, p0, conjugate = false)*BilinearForm(p1, p1, conjugate = false));
           elif clr="g" or clr="G" or clr="green" or clr="Green" then
              if prnt="y" then
               print( "Spread 2 [x,y] Points/Vectors wrt origin Green");
              end if;
               return -1/4*(p0[1]*p1[2] - p0[2]*p1[1])^2/(p0[1]*p0[2]*p1[1]*p1[2]);
           elif clr="r" or clr="R" or clr="red" or clr="Red" then
              if prnt="y" then
               print( "Spread 2 [x,y] Points/Vectors wrt origin Red");
               end if;
               return -(p0[1]*p1[2] - p0[2]*p1[1])^2/((p0[1]^2 - p0[2]^2)*(p1[1]^2 - p1[2]^2));
          end if;
          end proc:

>	sb:=spread(<3\|2>,<4\|-5>);

(2)

>	sg:=spread(<3\|2>,<4\|-5>,"g");

(3)

>	sr:=spread(<3\|2>,<4\|-5>,"r");

(4)

>	1/sb+1/sr+1/sg

(5)

>	sr:=spread(<3\|2>,<4\|-5>,"r","n");

(6)

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Download Q_2024-02-09_Alternative_Spelling_in_Proc.mw

Overload Procedures with default values ...

Asked: Ronan 1172 Product: Maple 2023

February 02 2024

2 9

The overloaded procedure here test returns based on 2 lists or 3 lists entered. The two list has a mixed input type with a default value. The default value of "a" can cause a problem if an explicit value in not entered for "a" in foo1. I not sure is the mixed input type is adding to the problem.
By changing the order of the procedures the problem is avoidable here. But this just a simple example. When there are 6 or so procedures it can be very difficult to select a correct ordering.

Is there a way around this, apart from don't have default values?

I could experiment with changing the input order in each proc but that would break up some logical input sequences on me.

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restart

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foo:=overload([
                        proc(P1::list,P2::list,a::algebraic:=4,$)
                         option overload;
                         print("2 lists");
                          end proc,

                       proc(P1::list,P2::list,P3::list,$)
                         option overload;
                         print("3 lists");
                          end proc
                       ]);

proc () option overload; [proc (P1::list, P2::list, a::algebraic := 4, ` $`) option overload; print("2 lists") end proc, proc (P1::list, P2::list, P3::list, ` $`) option overload; print("3 lists") end proc] end proc

(1)

>	foo([1,2],[3,4])

(2)

>	foo([1,2],[3,4],[4,7])

(3)

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foo1:=overload([


                       proc(P1::list,P2::list,P3::list,$)
                         option overload;
                         print("3 lists");
                          end proc,

                        proc(P1::list,P2::list,a::algebraic:=4,$)
                         option overload;
                         print("2 lists");
                          end proc
                       ]);

proc () option overload; [proc (P1::list, P2::list, P3::list, ` $`) option overload; print("3 lists") end proc, proc (P1::list, P2::list, a::algebraic := 4, ` $`) option overload; print("2 lists") end proc] end proc

(4)

>	foo1([1,2],[3,4]); #incorrect output

(5)

>	foo1([1,2],[3,4],4)

(6)

>	foo1([1,2],[3,4],[4,7])

(7)

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Download 2024-02-3_Q_Overload_proc_.mw

Check if '=' is or is not in an equation...

Asked: Ronan 1172

December 28 2023

3 6

How do i check if an equation or function does not contain an '=' sign, to convert it?

if eq:= a+b=c

If it has an '=' I can use eq1:=lhs(eq)-rhs(eq).

If eq=d+e+f there is no lhs/rhs and checking produces an error.

eq := a*x^2 + b*x = v;
                               2          
                      eq := a x  + b x = v

eq1 := lhs(eq) - rhs(eq);
                            2          
                         a x  + b x - v

eq2 := a*x^2 + b*x - v;
                               2          
                     eq1 := a x  + b x - v

lhs(eq1);
Error, invalid input: lhs received a*x^2+b*x-v, which is not valid for its 1st argument, expr
NULL;
has(eq,'=');
Error, invalid uneval
        Typesetting:-mambiguous(hasApplyFunction(eqcomma

          Typesetting:-mambiguous((equals), 

          Typesetting:-merror("invalid uneval"))))


has(eq2, rhs(eq2));
Error, invalid input: rhs received eq2, which is not valid for its 1st argument, expr
NULL;