Need help w/ 'unitless'? in matrix calculation

[usit]

I am frequently stopped in Mathcad14 by, for example) the message: =f(Unitless, [Unitless],Unitless, [Unitless]) --> [Unitless], which appears in the attached file 'Unitless_pgm.xmcd'. None of my terms have units or intend to use them.
The attached program is a test of steps trying to fill the first column of a 7x3 array.

<0 'negative values are not wanted'
if k=0 'should capture the first value of t'
if phi(m,0)<=t 'skips pre-used values'
then phi(k,0) <-- t fills the rest of the column
(I had hoped, but can't get the program to run)

The t <-- root(()) line works fine.

Need help urgently, a lot of hours have been wasted on this one!
ntelleck

[IRstuff]

You're calling a function without using the variable list. Mathcad is telling you that you need to specify 4 unitless variables, two of which are arrays.

TTFN,
Eden

[usit]

Double thanks eden_mei; one for the outright answer and the second for lucid explanation. Make that three thanks, your timing was equally valuable.

ed

[IRstuff]

Glad to be of help...

TTFN,
Eden

[StuartBruff]

On 12/14/2009 11:54:33 AM, merganser wrote:
== I am frequently stopped in Mathcad14 by, for example) the message: =f(Unitless,[Unitless],Unitless, [Unitless]) --> [Unitless], which appears in the attached file 'Unitless_pgm.xmcd'. None of my terms have units or intend to use them. The attached program is a test of steps trying to fill the first column of a 7x3 array.

Unfortunately, I've only got M13 at the moment, so can't look at your worksheet. If you save your worksheet in M11 format and post it, you will get a bigger audience (although only M12+ users will see the problem).

Mathcad evaluates a worksheet using static type checking (often referred to in this forum as SUC (static unit checking), which isn't strictly accurate but does convey the feelings of many users towards it).

In Help, do a search on 'type signature' in the Search type. Then look at the help on 'Defining a Function'. Halfway down you will (should) see a section called 'Function Type Signature' that will explain what the f(Unitless,... means. You will see that it affects functions even if they don't use units.

Stuart

[IRstuff]

Not even that subtle a problem, Stuart. The OP tried to evaluate a function that takes 4 parameters, with just the function name.

Obviously, Mathcad then tells you what the function name is defined as.


TTFN,
Eden

[StuartBruff]

On 12/14/2009 12:28:51 PM, eden_mei wrote:
>Not even that subtle a
>problem, Stuart. The OP tried
>to evaluate a function that
>takes 4 parameters, with just
>the function name.
>
>Obviously, Mathcad then tells
>you what the function name is
>defined as.

OK, Thanks, Eden

Stuart

... move along, folks, nothing to see, move along

[usit]

I'm very impressed with this new culture of mathcad forums that I've stumbled onto -- extremely helpful and timely.
Thanks stuartafbruff, you've added even more useful information.

ed

[StuartBruff]

On 12/14/2009 2:48:50 PM, merganser wrote:
==I'm very impressed with this new culture of mathcad forums that I've stumbled onto -- extremely helpful and timely.

The Collaboratory is the Original (Mathsoft) forum and is still maintained by PTC. I've found it helpful and responsive since I joined (over 6 years ago).

== Thanks stuartafbruff, you've added even more useful information.

No worries.

Stuart