Error in example: "And here is an example for user-supplied matrix operation class."

[linuxfreebird]

I tried compiling the last example mentioned in https://spectralib.org/quick-start.html titled "And here is an example for user-supplied matrix operation class." and I discovered there was a type mismatch between the example and the inline method called perform_op in Spectra/MatOp/internal/ArnoldiOp.h. The example uses double* and ArnoldiOp.h uses const double*, so I changed all const double* to double* in ArnoldiOp.h and it compiled and ran correctly. I am unsure which implementations was the author's original intent.

[yixuan]

Hi @linuxfreebird, thanks for pointing out. Your finding is correct, but the problem is actually in the example. The x_in argument should be const double*, since the input is not meant to be modified. The examples are pretty old and I forgot to change accordingly. Now they have been fixed. Thank you.