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# WC

WC = [real]
Default: WC = 1000.

Description: WC specifies the weight factor for each step in Broyden mixing scheme (IMIX=4).

Set all weights identical to WC (resulting in Pulay's mixing method), up to now Pulay's scheme was always superior to Broyden's 2nd method.
Switch to Broyden's 2nd method, i.e., set the weight for the last step equal to 1000 and all other weights equal to 0.
• WC<0 (implemented for test purposes: not recommended)
Try some automatic setting of the weights according to:
${\displaystyle W_{\rm {iter}}=0.01|{\rm {WC}}|/||\rho _{\rm {out}}-\rho _{\rm {in}}||_{\rm {precond.}}\,}$
in order to set small weights for the first steps and increasing weights for the last steps.