与pdpotrf参数混淆 [英] Confused with pdpotrf arguments

问题描述

我想在分布式环境中进行Cholesky因式分解。为此，我使用 pdpotrf（）。但是，我正在努力了解函数所需的参数，并且没有提供如何使用它的C示例（并且一个例子真的很棒）。

I want to do a Cholesky factorization in a distributed environment. For that purpose, I use pdpotrf(). However, I am struggling understanding the parameters needed by the function and they provide no C example on how to use it (and an example would be really great to have).

假设我有一个NxX矩阵我想分解。那么，参数应该有什么值？ uplo ， a 和信息 。其余的？

Assume I have a NxX matrix I want to factorize. Then, what values should the parameters have? uplo, a and info are well defined in my mind. How about the rest?

n 应该等于N。但是， desca ， ia 和 ja 混淆我。此外， desca 是全局和本地的，我不能理解的东西。有人可以解释吗？也许有一个方法的例子（不一定是代码，因为我想知道，而不只是复制粘贴）。

n should be equal to N I would say. However, desca, ia and ja are the ones that confuse me. Moreover, desca is global and local, something that I can't understand. Can someone explain? Maybe with an approach-example (not necessarily code, since I want to understand, not just copy paste).

_{>知道任何Fortran。}

推荐答案

从 answer ，我们有：

IA 和 JA ：这些参数用于在较大的矩阵中提供全局矩阵的起始行和列。它们只有在你有一个大矩阵并且只想要一个子矩阵的Cholesky分解时才是相关的。在你的情况下， IA 和 JA 都必须 1 ！

IA and JA: those parameters are meant to provide the starting row and column of your global matrix inside a larger matrix. They are only relevant if you have a big matrix and only want the Cholesky decomp of a submatrix. In your case, IA and JA both have to be 1!

再次，从这个答案，存在一个链接，描述 desca ：

Again, from this answer, there exists a link, that describes desca:

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