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On Fri, 01 Mar 2024 12: 51: 45 -0600, Junchao Zhang wrote: >> The preferred method then is to use MatSetValues() for the copies (or >> possibly MatSetValuesRow() or MatSetValuesBlocked())? > MatSetValuesRow() Thanks >> The
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<meta charset="us-ascii"></head><body><pre style="font-family: sans-serif; font-size: 100%; white-space: pre-wrap; word-wrap: break-word">On Fri, 01 Mar 2024 12:51:45 -0600, Junchao Zhang wrote:
>> The preferred method then is to use MatSetValues() for the copies (or
>> possibly MatSetValuesRow() or MatSetValuesBlocked())?
> MatSetValuesRow()
Thanks
>> The term "Preallocation" is confusing to me. For example,
>> MatCreateMPIBAIJWithArrays clearly states in the doc that arrays are copied
>> (<a href="https://urldefense.us/v3/__https://petsc.org/release/manualpages/Mat/MatCreateMPIBAIJWithArrays/__;!!G_uCfscf7eWS!cls7psuvaRuDYuXpUpmU7lcEhX9AO0bb3qTpszwuTNP8LPPrJkCzoaHIdJCzxPR36D7SLYs9MKCxqMBKRnSQc8s$">https://urldefense.us/v3/__https://petsc.org/release/manualpages/Mat/MatCreateMPIBAIJWithArrays/__;!!G_uCfscf7eWS!cls7psuvaRuDYuXpUpmU7lcEhX9AO0bb3qTpszwuTNP8LPPrJkCzoaHIdJCzxPR36D7SLYs9MKCxqMBKRnSQc8s$</a>), I
>> would then assume PETSc maintains internal storage for it. If something is
>> preallocated, I would not make that assumption.
>"Preallocation" in petsc means "tell petsc sizes of rows in a matrix", so that
>petsc can preallocate the memory before you do MatSetValues(). This is clearer
>in <a href="https://urldefense.us/v3/__https://petsc.org/release/manualpages/Mat/MatMPIAIJSetPreallocation/__;!!G_uCfscf7eWS!cls7psuvaRuDYuXpUpmU7lcEhX9AO0bb3qTpszwuTNP8LPPrJkCzoaHIdJCzxPR36D7SLYs9MKCxqMBKrYGemdo$">https://urldefense.us/v3/__https://petsc.org/release/manualpages/Mat/MatMPIAIJSetPreallocation/__;!!G_uCfscf7eWS!cls7psuvaRuDYuXpUpmU7lcEhX9AO0bb3qTpszwuTNP8LPPrJkCzoaHIdJCzxPR36D7SLYs9MKCxqMBKrYGemdo$</a>
Thanks for the clarification!
All best,
--
fabs
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