Does anyone know how to fix this....

[Diquan]

I don't understand that "must be an scalar", the number is already an scalar!

 

[ChrMeissner]

Hello,

your second variable "rho" is a matrix with the dimension 1x1 and no skalar (because it stands in brackets).

The easiest way to fix this, is to define a new variable like this: p = r[0,0

That extractes the 0,0-element from this matrix and writes it to a scalar variable.

That would work but I think, your mistake is in the calculation before, rho shouldn't be a 1x1-matrix. This occurs if you multiple a 3x1 with a 1x3 matrix as vectorproduct. Instead of this you can use the scalarproduct (3x1)^T * (1x3). But there may be other possibilities.

Sorry for bad spelling, I've only spare time.
Christian

 

[Diquan]

 

[Diquan]

I also tried to fix it with the solution that you gave me, but i don't understand it, is:

p = r[0,0

Now, i tried to write that but nothing happend, gave me an error, can you take a picture of that, like an example or something?

Thanks!

 

[IRstuff]

Your problem starts with the definition of d, since its result shows up with a parenthesis around a single number, indicating a 1-D vector.

The simplest solution is to select the end of the definition of d and tack on [0. Since the vector is 1-D, [0,0 results in an error.

TTFN

 

[jghrist]

The problem is that the vlookup function returns a vector.

From Mathcad Help:

vlookup(z, A, c) Looks in the first column of a matrix, A, for a given value, z, and returns the value(s) in the same row(s) in the column specified, c. When multiple values are returned, they appear in a vector.

Apparently when a single value is returned, it appears in a one row vector.

IRstuff's solution should work.

 

[Diquan]

HEY!!, that's perfect!!!, worked BEAUTIFUL!!!

Thanks very much!!!

here it is........