hi, everyone<br><br>My codes are as follows:<br>&nbsp;      ierr=MatGetSubMatrices(tempM_mat,1,&amp;is_row,&amp;is_col,MAT_INITIAL_MATRIX,&amp;tempA_mat); CHKERRQ(ierr);<br>&nbsp;      A_mat=*tempA_mat;<br>&nbsp;      ierr=MatDestroy(tempM_mat);CHKERRQ(ierr);<br>
&nbsp;      ierr=MatGetSize(A_mat,&amp;M,&amp;N);CHKERRQ(ierr);<br>&nbsp;      //AtA<br>&nbsp;      ierr=MatMatMultTranspose(A_mat,A_mat,MAT_INITIAL_MATRIX,fill,&amp;AtA_mat);<br><br>I get a seqdense submatrix &quot;A_mat&quot; by MatGetSubMatrices().&nbsp;I&nbsp;further&nbsp;get&nbsp;At*A&nbsp;by&nbsp;MatMatMultTranspose().&nbsp;However,&nbsp;I&nbsp;meet&nbsp;an&nbsp;error:<br>
 &quot; ** On entry to DGEMM  parameter number  8 had an illegal value&quot;<br><br>I debug my codes. In&nbsp;MatMatMultTranspose_seqdense_seqdense(),&nbsp;the&nbsp;codes&nbsp;call&nbsp;<br>&quot;BLASgemm_(&quot;T&quot;,&quot;N&quot;,&amp;m,&amp;n,&amp;k,&amp;_DOne,a-&gt;v,&amp;a-&gt;lda,b-&gt;v,&amp;b-&gt;lda,&amp;_DZero,c-&gt;v,&amp;c-&gt;lda);&quot;<br>
I don&#39;t know the meaning of the 8th parameters&quot;&amp;a-&gt;lda&quot;. In my codes, its value is &quot;0&quot;.<br><br>Are&nbsp;there&nbsp;any&nbsp;problems&nbsp;in&nbsp;my&nbsp;codes?&nbsp;could&nbsp;you&nbsp;give&nbsp;me&nbsp;some&nbsp;advice?&nbsp;thanks&nbsp;a&nbsp;lot.<br><br>Regards,<br>
Yujie&nbsp;<br>