vector_mulv_addv testing broken about lib_dsp

[henkmuller]

I fixed it on my fork.

Two observations:

1. The test cases don’t test for vectors longer than 5 elements; there is a lot of special code for vectors with length greater than 7
2. The special code assumes that all arrays are 64 bit aligned; which they aren’t in the example program

I suggest we disable the special code for vectors longer than 7 elements.

[johned0]

Me too, Henk Pull request generated : #87 The special code does give performance improvements. The arrays in the example are global so should be 64 bit aligned. J

[johned0]

BTW, I had a chat with Peter, on Monday.
I've offered to try to find some time to spend working on lib_dsp, to make sure all the examples and documentation etc are correct and all the pull requests merged etc.
Not sure when though, but hopefully soon.
J

[henkmuller]

I appreciate that the special code speeds it up; but if there is no test case it is quite hard to see that it actually works. Re alignment: I hadn't appreciated that all global arrays are 64-bit aligned.

[johned0]

Agreed, Henk, this is one of the areas that needs tidying up so test cases should cover longer arrays

[henkmuller]

I renamed the issue to reflect that the code is probably ok, but it is the testing that needs fixing.

[johned0]

indeed

[oscarbailey-xmos]

I've written some tests for the dsp_vector functions which seem to show that the muls_addv, muls_subv, mulv_addv, and mulv_subv do not give correct outputs for vector lengths > 7.

My Fork

[oscarbailey-xmos]

Related issue: #123