Solve block issue with Mathcad 15, works in Mathcad prime 3.0

[rkalebbo]

Hello,

I need to solve a system of simultaneous equations to find reference parameters for a PV model. I have entered the same set of equations in Mathcad 15 and Mathcad prime 3.0. As far as I can see the equations are exactly the same in both worksheets. The problem I'm having is that Mathcad 15 is not returning an answer although I get a solution in Mathcad prime 3.0. I would like to resolve the issue in Mathcad 15 as I need to plot graphs and do some further analyses using functionality that is available in Mathcad 15 but not prime. I also have no way of telling which algorithm Mathcad Prime  3.0 applied to return the solution so I can't even replicate that in Mathcad 15.

I also noticed that if I change the guess values in prime and then change back to original guess values that returned a solution, sometimes mathcad prime 3.0 doesn't return a solution also, no idea why.

(Note that for a valid solution 1<a<2 but when I include this constraint mathcad prime 3.0 won't return a solution even though the solution it gives initially meets this constraint)

Any assistance to resolve this will be greatly appreciated!!!

[AlvaroDíaz · Accepted solution]

Hi.

Just delete the equal after Find. Mathcad 15 don't like vectors with different units.

Best regards.

Alvaro.

[rkalebbo]

AlvaroDíaz It worked! Thank you very much

There really should be something in the help menu to clarify that for inexperienced users Toby Metcalf‌

[-MFra-]

[rkalebbo]

F.M.‌ this looks like a good work around  to resolve the issue of different units within the vector. The solution proposed by AlvaroDíaz‌ i.e. deleting the equal sign after "Find" is more appropriate though since it doesn't distort the meaning of the variables; the solution can then be extracted from the assigned variables (Iph_stc, Io_stc ...etc)

Thank you for your input

[-MFra-]

However, I find that the results are different from those obtained with Prime.

Bye

[rkalebbo]

I noticed that too... probably because of different algorithms used...