petsc-3.10.5 2019-03-28

VecStepMax

Returns the largest value so that x[i] + step*DX[i] >= 0 for all i

#include "petscvec.h"  
PetscErrorCode VecStepMax(Vec X, Vec DX, PetscReal *step)

Collective on Vec

	X	- vector with no negative entries
	DX	- a step direction, can have negative, positive or zero entries

step -largest value such that x[i] + step*DX[i] >= 0 for all i

For complex numbers only compares the real part

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