For brevity, it is assumed in what follows that the 1st two arguments are arrays.  Either or both of them may be lists or lists of lists.

If the last argument is dontprint  then the lprinting of intermediate test results is suppressed.  Otherwise, the results are lprinted in an array-like manner, giving a visual representation of the entries which agree and disagree.

If only 2 arguments are given, or if 3 arguments are given and the 3rd one is dontprint, then a straight boolean comparison of the entries of the input arrays is done.

Otherwise, testfloat is invoked to do the comparison of the entries in the input arrays.  All arguments to comparray after the first two (but excluding dontprint, if present) are passed to testfloat as the 3rd, 4th, etc parameters to that routine.  Note that this implies that the same error bound will be applied to all entries in the arrays, and that the input array B is considered to contain the ``correct'' values. See testfloat for more details.

In either case, if the dimensions of the input arrays do not match, no further processing is done.

If any of the entry comparisons fail, comparray returns false. Otherwise it returns true.

$A≔\mathrm{Array}\left(\left[\left[1\,2\,3\right]\,\left[4\,5\,6\right]\,\left[7\,8\,9\right]\right]\right)\:$

$B≔\mathrm{Array}\left(\left[\left[1\,2\,4\right]\,\left[7\,5\,6\right]\,\left[7\,8\,9\right]\right]\right)\:$

$\mathrm{comparray}\left(A\,B\,\mathrm{dontprint}\right)$

$\mathrm{false}$

$\mathrm{comparray}\left(A\,B\right)\:$

[true, true, false]
[false, true, true]
[true, true, true]

$A≔\mathrm{Array}\left(\left[\left[1.23\,4.56\,7.89\right]\right]\right)\:$

$\mathrm{comparray}\left(A\,\left[\left[1.26\,4.55\,7.90\right]\right]\,1\,\mathrm{digits}=3\right)\:$

[[false, 3., `ulps `], true, true]

$\mathrm{comparray}\left(\left[1\,2\right]\,\left[1\,2\right]\,\mathrm{dontprint}\right)$

$\mathrm{true}$