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Adding/subtracting vectors

To: <petsc-users@xxxxxxxxxxx>
Subject: Adding/subtracting vectors
From: "John R. Wicks" <jwicks@xxxxxxxxxxxx>
Date: Sun, 12 Aug 2007 19:57:26 -0400
Importance: Normal
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It seems that the only way to add two vectors is to use VecAXPY(x,1,y);
likewise, to subtract one must call VecAXPY(x,-1,y).  Are these routines
optimized to recognize these special cases to avoid the extraneous scalar
multiplications?

Follow-Ups:
- Re: Adding/subtracting vectors
  - From: Barry Smith

References:
- Re: How can I use BICGStab on a matrix with zero entries on the diagonal
  - From: Zhu Liang

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