About the trouble of MSC Nastran 2018

A serious problem was found in MSC Nastran2018. For details, please see the notice from MSC.

Dear MSC Nastran users,
We sincerely thank you for using our products.

We have noticed that MSC Nastran 2018 has found a problem leading to the wrong result.

This malfunction is due to the fact that in the subroutine MPYAD which performs matrix multiplication and addition, only when performing the multiplication of the matrix of DENSE, SPARSE, and DENSE - SPARSE type, and unable to secure sufficient memory and cause "out-of-core". Currently we are investigating the impact of defects and we plan to provide the modified program by September 10, 2018. MSC Nastran 2018.1.1 (replacement of MSC Nastran 2018.0, 2018.0.1, and 2018.1) and MSC Nastran 2018.2.1 (replacement of MSC Nastran 2018.2) are ready for downloading from MSC Software Solutions Download Center (SDC) An email will be sent.

In addition to identifying the cause of incorrect results, we also established a method to identify the analysis without problems.
We recommend to check the .f04 file (only jobs with DIAG19 in the input file) of the jobs analyzed by MSC Nastran 2018.0, 2018.0.1, 2018.1, or 2018.2 and you verify that the DENSE, SPARSE, and DENSE-SPARSE methods of the MPYAD subroutine did not go out-of-core with multiple matrices. If the message "ALL MATRICES OUT OF CORE" is not output to the .f04 file of the job that had DIAG19, there is no problem with the result.
If the MPYAD subroutine has enough memory to perform matrix operation, or if only a single matrix is ​​out of core, there is no problem with the result. If there is enough open core memory in the MPYAD subroutine, a message like Exhibit A (reference material A) will be displayed for different calculation methods.

Only when the MPYAD subroutine has insufficient memory and all matrices are out of core, the possibility that the analysis result is incorrect is high. In that case, you have to decide that the analysis result is wrong. If the message "ALL MATRICES OUT OF CORE" is output as shown in Exhibit B (reference material B), increase the open core memory and re-execute the analysis in order to obtain the correct result. Proper memory capacity can be estimated with diagnostic messages in the .f04 file.

We recommend that using the version up to MSC Nastran 2017.1 until wre prepare the modified program.
Customers who only have MSC Nastran 2018 should specify as much memory as possible and add DIAG 19 to the input file and execute it. Check the obtained .f04 file and if there is no message "ALL MATRICES OUT OF CORE", there is no problem in the calculation result.
We sincerely apologize for your inconvenience and inconvenience to our customers.