these are system classes that are part of the product that do exists in the new installed version in the %SYS namespace.

If the Studio screenshot you have posted is not from the %SYS namespace (it really does not seems so), then probably the System package is mapped to that namespace, possibly also the related globals. But...I'm guessing here from the little details and context you provide.

For your response I assume you are searching for a class used by a Business Host component within a production.

Using IRIS you can search for that, and much more, using "Interface Reference" within the Management portal:

Unfortunately you are using an old version where this feature is not available.

Add this to the (possibly long) list of good reasons to move to IRIS.

For DEFLATE use:

open tmpFile:("WNS":::/COMPRESS="DEFLATE"):0

	set original = "my very long string which needs to be deflated"
	zwrite original

	write !,"using $system.Util.Compress",!
	set compressed = $system.Util.Compress(original, "zlib")
	set compressed=$e(compressed,4,*-5)
	zwrite compressed
	zzdump compressed write !
	set deflated = $system.Encryption.Base64Encode(compressed, 1)
	zwrite deflated

	set tmpFile = ##class(%File).TempFilename("bin")

	set io = $io
	open tmpFile:("WNS":::/COMPRESS="DEFLATE"):0
	use tmpFile
	write original
	use io
	close tmpFile

	set stream = ##class(%Stream.FileBinary).%New()
	set stream.Filename = tmpFile
	set stream.RemoveOnClose = 1
	set compressed = stream.Read(stream.Size)  

	write !,"using open file",!
	zwrite compressed
	zzdump compressed write !
	set deflated = $system.Encryption.Base64Encode(compressed, 1)
	zwrite deflated

	write !,"Expected",!
	set base64 = "y61UKEstqlTIyc9LVyguKcoEUuUZmckZCnmpqSnFCiX5CkmpCimpaTmJJakpAA=="
	set compressed = $system.Encryption.Base64Decode(base64)
	zwrite compressed
	zzdump compressed write !

Result:

original="my very long string which needs to be deflated"
 
using $system.Util.Compress
compressed="Ë­T(K-ªTÈÉÏKW(.)Ê"_$c(4)_"Rå"_$c(25,153)_"É"_$c(25,10)_"y©©)Å"_$c(10)_"%ù"_$c(10)_"I©"_$c(10)_")©i9"_$c(137)_"%©)"_$c(0)
 
0000: CB AD 54 28 4B 2D AA 54 C8 C9 CF 4B 57 28 2E 29         Ë­T(K-ªTÈÉÏKW(.)
0010: CA 04 52 E5 19 99 C9 19 0A 79 A9 A9 29 C5 0A 25         Ê.Rå..É..y©©)Å.%
0020: F9 0A 49 A9 0A 29 A9 69 39 89 25 A9 29 00               ù.I©.)©i9.%©).
deflated="y61UKEstqlTIyc9LVyguKcoEUuUZmckZCnmpqSnFCiX5CkmpCimpaTmJJakpAA=="
 
using open file
compressed="Ë­T(K-ªTÈÉÏKW(.)Ê"_$c(4)_"Rå"_$c(25,153)_"É"_$c(25,10)_"y©©)Å"_$c(10)_"%ù"_$c(10)_"I©"_$c(10)_")©i9"_$c(137)_"%©)"_$c(0)
 
0000: CB AD 54 28 4B 2D AA 54 C8 C9 CF 4B 57 28 2E 29         Ë­T(K-ªTÈÉÏKW(.)
0010: CA 04 52 E5 19 99 C9 19 0A 79 A9 A9 29 C5 0A 25         Ê.Rå..É..y©©)Å.%
0020: F9 0A 49 A9 0A 29 A9 69 39 89 25 A9 29 00               ù.I©.)©i9.%©).
deflated="y61UKEstqlTIyc9LVyguKcoEUuUZmckZCnmpqSnFCiX5CkmpCimpaTmJJakpAA=="
 
Expected
compressed="Ë­T(K-ªTÈÉÏKW(.)Ê"_$c(4)_"Rå"_$c(25,153)_"É"_$c(25,10)_"y©©)Å"_$c(10)_"%ù"_$c(10)_"I©"_$c(10)_")©i9"_$c(137)_"%©)"_$c(0)
 
0000: CB AD 54 28 4B 2D AA 54 C8 C9 CF 4B 57 28 2E 29         Ë­T(K-ªTÈÉÏKW(.)
0010: CA 04 52 E5 19 99 C9 19 0A 79 A9 A9 29 C5 0A 25         Ê.Rå..É..y©©)Å.%
0020: F9 0A 49 A9 0A 29 A9 69 39 89 25 A9 29 00               ù.I©.)©i9.%©).
 

I'm no expert in vectors so I might be wrong, however it seems to me that the problem is not in the VECTOR_COSINE() function, instead it seems to me the problem is in the TO_VECTOR() function inside VECTOR_COSINE().

The documentation for the TO_VECTOR() function for the first argument (data) says:

If you are using TO_VECTOR in Dynamic SQL, other data types are accepted. The allowed data types are determined by the SelectMode. If the SelectMode is ODBC or Display, the data argument may be passed in as a DynamicArray, as well as a string. If the SelectMode is Logical, the data argument must be entered as a $vector.

In this case the SelectMode is Logical and it does not seems to me that the TO_VECTOR() first argument is passed as $vector.

When you run $zf(-100) from IRIS session terminal the external process is run in the OS context (secutity/permissions) of the OS user loggen in.

When $zf(-100) is run by a storedproc or studio is run in the OS context (secutity/permissions) of the OS user used by the IRIS instance.

You have permission and/or environment issue.

Why run python using $zf(-100)? You can use embedded python to avoid this issues, it is simpler and have better performance.

I'm not sure what "HL7 Reference Guide" exactly means for you, however, within "health enabled products" (IRIS for Health, Healthhare Connect, Healthshare UCR etc.) there are "HL7 Schemas" for all HL7 v2 variants up to 2.8.2.

Can be accessed from Management Portal Interoperability -> Interoperate -> HL7 v2.x -> HL7 v2.x Schema Structures.

There, for each version you can browse in detail the HL7 message structure, segments, field, subfields etc down to code tables associated to coded entries/fields.

If you don't have IRIS for Health, you can download IRIS for Health community edition that is free for non commercial/production use (check license for details).

This is interesting.

It is evident that when the class is compiled IRIS parse the <PropertyName>Computation() method(s) to find out what properties are actually used/referenced/passed to the cols.getfield() method(s), then it use this information to set the "fields" multidimensional property of %Library.PropertyHelper class before calling the <PropertyName>Computation() method.
This way only the used properties are set in the "fields" multidimensional property of %Library.PropertyHelper class.
This optimization improves performance in case of a class with many properties, possibly "complex" properties (calculated, references etc.) and I believe this is why has been implemented.

The "parser" is...simple, very simple.

To prove this assumption I wrote a little sample:

Class Community.Computation Extends %Persistent
{

Property FirstName As %String;
Property LastName As %String;
Property FullName As %String [ SqlComputed ];
ClassMethod FullNameComputation(cols As %Library.PropertyHelper) As %String
{
    ; cols.getfield("FirstName")
    ; cols.getfield("LastName")
    return ..FullNameComputationSub(cols,"FirstName","LastName")
}

ClassMethod FullNameComputationSub(cols As %Library.PropertyHelper, p1 As %String, p2 As %String) As %String
{
    return cols.getfield(p1)_" "_cols.getfield(p2)
}

/// do ##class(Community.Computation).test()
ClassMethod test()
{
    set obj=..%New()
    set obj.FirstName="Enrico"
    set obj.LastName="Parisi"
    write obj.FullName,!
}

}

If I run test() I get:
 

do ##class(Community.Computation).test()
Enrico Parisi

If I remove the commented line "; cols.getfield("FirstName")" and run test() again:

do ##class(Community.Computation).test()
 Parisi

If you look at your error:

"set cols.fields("ropert")={ropert}'"

That's the parser that found "cols.getfield(property)" and assuming a string was passed removed the first and last characters (assuming were double quotes), so it got "ropert".

Bottom line, cols.fields() can only be used passing a string constant with a property name.