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Let's vote for suggestions and bugs
09-24-2018, 07:34 PM
Post: #74
RE: Let's vote for suggestions and bugs
I'm not a programmer and I just use basic to intermediate of Prime, but I'm still concerned about the previous problem that I posted before, as it is a quite simple operation and I expect to have reliable answers from the calculator. I will describe the same example but with a different perspective.

Matrix A and B are related to a 2x2 linear system to be solved.
A=
| -19.3|
| 12|

B=
|-270510 510|
|510 -2710|

In HP48, HP50 and Prime (CAS View) you can divide A/B (and the calculators understand this single operation as B^(-1) x A) or you can also do it as B^(-1) x A indeed.

The answer you get is the correct one:

| 6.30207608396E-5|
|-4.41618428486E-3|

But in Prime (HOME View) you get a wrong answer:

|7.13720385033E-5|
|-4.4296159231E-3|

The answer is even worse if you decide to use the Linear Equation Solver app:

| 0|
|-4.41618428485E-3|

The problem is due to the algorithm internally and weirdly rounding just part of B^(-1) to zero in the HOME view. I could use inv(B) but I think it is boring and time consuming compared to a simple division. And more important, I think the calculator should have the same behavior as of presenting accurate answers in both views.

My question is how much can I trust in HOME view and Linear Equation Solver App of HP Prime. I personally likes the HOME view because of the RPN system...
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Messages In This Thread
RE: Let's vote for suggestions and bugs - ammonteir - 09-24-2018 07:34 PM
BREAK still reboot the calc - Oulan - 07-21-2019, 09:12 AM



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