markrogoyski / math-php / 6793412299

100%

master: 100%

push

github

Replace array_search with floating-point filter in `Eigenvector::eigenvectors` (#473)

* Test Eigenvectors can handle numerical imprecision

To mimic the error found in the QR algorithm, we have to test with matrices that have duplicate eigenvalues and introduce numerical precision errors.

To do this, a list of perturbed eigenvalues is passed to the eigenvectors method. The perturbation is achieved by adding a random +/- offset on an order of magnitude smaller than the default matrix error. This should allow the math to work out fine while causing the floating point comparison to fail.

* Replace array_search with floating-point filter

array_search seems to fail in most cases when looking for a float in an array of floats. And even if it does find a match, if the key is 0, php evaluates `!0` to true.

To find a match, we can instead loop through and compare the numbers with `Arithmetic::almostEqual` and then explicitly check if `$key === false`

6 of 6 new or added lines in 1 file covered. (100.0%)

7543 of 7549 relevant lines covered (99.92%)

184.94 hits per line