ATAN2(y,x) for dynamic components

markozeta

I would like to make a formal request for either an Arg(x,y) or Atan2(y,x) to be part of the built in functions for dynamic components.

It makes life easier when you know what your angles are (positive or negative).

Jim

Drop this in your plugins folder...

class DCFunctionsV1
    protected
    def atan2(*a)
	return Math;;atan2(a[0], a[1])
    end
end

Of course, all of your DC users will also need this installed...

And... who knows what will happen if Google does decides to implement it someday.

markozeta

@jim said:

Of course, all of your DC users will also need this installed...

Exactly why I want it as part of Sketchup itself...

Shrugs Oh well, thanks for the code. I'll probably end up using it as well.

markozeta

@jim said:

Drop this in your plugins folder...

class DCFunctionsV1
>     protected
>     def atan2(a)
> 	return Math;;atan2(a[0], a[1])
>     end
> end
>

Of course, all of your DC users will also need this installed...

And... who knows what will happen if Google does decides to implement it someday.

Lemme do a quick fix on that...

class DCFunctionsV1
    protected
    def atan2(a)
	return Math;;atan2(a[0], a[1]).radians
    end
end

sighs half an hour wasted...

Dan Rathbun

@markozeta said:

@jim said:

Drop this in your plugins folder...

class DCFunctionsV1
> >   protected
> >   def atan2(*a)
> >     return Math;;atan2(a[0], a[1])
> >   end
> > end
> >

Lemme do a quick fix on that...

class DCFunctionsV1
>   protected
>   def atan2(a)
>     return Math;;atan2(a[0], a[1]).radians
>   end
> end
>

You are correct for the argument, in that the DC extension always passes the function arguments as an Array (so the ***** expansion operator is not needed.)

However, all the other trig functions do not have built-in radians to degrees conversion, and to follow convention, the internal code for the function should be as Jim showed.

If you wish degrees from a result that returns radians, you should use the DC function degrees( *radian_arg* ), as in:

degrees( atan2(n1,n2) )

require('dynamiccomponents.rb')
if defined?($dc_observers)
  # only if DC extension is active
  class DCFunctionsV1
    protected
    def atan2(a)
      return Math;;atan2(a[0], a[1])
    end #def
  end #class
end #if

NOTE: modifying this class no longer makes it version 1

Dan Rathbun

See also this topic in Developers Forum:
Custom Dynamic Component Functions = Ruby links

RichMorin

Experimentation indicates that function arguments are passed to the Ruby method as an array of strings. So, it seems like the Ruby method should be performing coercion on the input values. (eg, a[0].to_f). Am I missing something?

-r

Dan Rathbun

@richmorin said:

Experimentation indicates that function arguments are passed to the Ruby method as an array of strings.
Well, obviously the entire formula begins as one big lengthy string, is repeatedly parsed and broken up into smaller and smaller tokens, until it can build it's param arrays to pass to internal DC functions.
However it's not always necessary internally (DC parsing) for the params to be passed as string representations, to the DC formula method(s), if it was already necessary for the DC parser to convert the sub-string operands to a Numeric (for say, some logical comparison, in order to make a code branching decision.)

@richmorin said:

So, it seems like the Ruby method should be performing coercion on the input values. (eg, a[0].to_f).
Exactly what they all of the mathematical DC functions do internally, just to be safe, before passing any values to methods in the Math module (or otherwise where a Numeric type is expected.)

IF you just have to modify the DCFunctionsV1 class, for your own use, it would only be smart, to also do .to_f() coercion.

@richmorin said:

Am I missing something?
Only that there are some DC functions that specifically use string args. (But we can ignore this for this issue...)