topic Re: Bug - matrix limit in Mathcad

Bug - matrix limit

DJF — Thu, 03 May 2018 13:14:39 GMT

I seem to have found a bug in Prime 4.0. When specifying an array of 4767 elements it stops working. But only if the program is defined as [a b]:=, it works fine if it's a:=. This picture explains it better than I can. So, I have a work around, but my questions are:

a.) It's a bug, right?

b.) Any reason why it would do that?

Thanks,

Re: Bug - matrix limit

LucMeekes — Wed, 28 Mar 2018 14:53:31 GMT

For the situation where it works. What are the values of a and b following the assignment.

(Of course) this works with no problem in Mathcad 11. But I get this:

That is: a and b are each the same set of two vectors.

Success!
Luc

Re: Bug - matrix limit

DJF — Wed, 28 Mar 2018 14:53:39 GMT

I get this as results when it works. (just what I'd expect to get)

The workaround gives this:

Re: Bug - matrix limit

Werner_E — Wed, 28 Mar 2018 14:59:14 GMT

I can only confirm that its a bug in Prime.

There is no problem of that kind in Mathcad 15

When I go up to 10^7 I get a "System.OutOfMemoryException".

Re: Bug - matrix limit

Werner_E — Wed, 28 Mar 2018 15:08:27 GMT

The error even occurs if we don't create variables in the program and don't calculate anything!

The error message tells us that either an overflow occured or an infinite recursion ... sure!

Re: Bug - matrix limit

DJF — Thu, 27 Oct 2022 13:17:28 GMT

I'd forgotten about this bug until it bit me again today. But what is strange is that this case works fine in Prime 4, 5 and 6. But in 7 I get the error. (don't have v8 to test)

Re: Bug - matrix limit

Werner_E — Thu, 27 Oct 2022 14:09:31 GMT

Curious, but in this case it can be said that turning a range into a vector is an undocumented feature and so subject to be changed without notice.

Does the error also pops up if you create the vector in "classic" legal manner?

I can only test with P6 and, as you wrote, no error here with both methods.

Re: Bug - matrix limit

DJF — Thu, 27 Oct 2022 15:00:09 GMT

Thanks Werner. Yes, the classic method works in P7. (I'm so used to the shortcut I forget about that)

Re: Bug - matrix limit

ttokoro — Thu, 27 Oct 2022 23:29:32 GMT

Prime 8 can do. But symbolic engine needs long time to show the results.