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# M CONSTR

**M_CONSTR** = [real array]

Default: **M_CONSTR** = 3*NIONS*0.0

Description: **M_CONSTR** specifies the desired local magnetic moment (size and/or direction) for the constrained local moments approach.

The **M_CONSTR** tag sets the desired size and/or direction of the integrated local magnetic moments in cartesian coordinates.

For each ion 3 coordinates must be specified, i.e., for a system of *N* ions

M_CONSTR= M_1x M_1y M_1z M_2x M_2y M_2z .... M_Nx M_Ny M_Nz

For I_CONSTRAINED_M=1 the norm of this vector is meaningless since only the direction will be constrained. For I_CONSTRAINED_M=2 both the norm as well as the direction of the moments specified by means of **M_CONSTR** are subject to constraints.

Setting

M_CONSTR= ... 0 0 0 ...

for a certain ion is equivalent to imposing no constraints on the integrated local magnetic moment at this ionic site.

For an explanation of the constrained local moments approach see the description of the I_CONSTRAINED_M tag.

## Related Tags and Sections

I_CONSTRAINED_M, LAMBDA, RWIGS, LNONCOLLINEAR