Trouble returning array

Forum|Forum|3 years ago
August 4, 2022
3 replies
1393 views

I'm having trouble returning an array for a term in an equation. I have a spreadsheet that should generate a P-M diagram for a column. It correctly calculates the array of P values, The spreadsheet will return an array of M values, but they are incorrect. When picking the equation for M apart bit by bit, I have found that one term returns a scalar value rather than an array. Preceding calculations for this term correctly return arrays, but this one does not. The term in question in the attached file is c*((ri^2) - y^2). Even when I rewrite the variable c in terms of y, it still returns the same single number. For reference, when y= -11.5, the correct value should be 0, and when y= -11.25, the correct value for the term above should be 18.876 in^3. What am I doing incorrectly?

1_test.zip

Best answer by Werner_E

I can't open your worksheet with my Prime 6 but I guess you want to now about and should use vectorization.

If c is a vector and either ri or y (or both) is a vector, too, then you are multiplying vector c with another vector and Prime of course uses the vector dot product and the result is a scalar. If you vectorize the expression, you should get a vector as result.

A good rule of thumb is - if you want an operation to be done element wise, don't rely on Primes implicit vectorization but rather apply vectorization explicitly.

W

Werner_E

Answer

25-Diamond I

I can't open your worksheet with my Prime 6 but I guess you want to now about and should use vectorization.

If c is a vector and either ri or y (or both) is a vector, too, then you are multiplying vector c with another vector and Prime of course uses the vector dot product and the result is a scalar. If you vectorize the expression, you should get a vector as result.

A good rule of thumb is - if you want an operation to be done element wise, don't rely on Primes implicit vectorization but rather apply vectorization explicitly.

T